reintegration with tip

CHANGES.txt

+===============================================================================
+Welcome to the C# port of Google Protocol Buffers, written by Jon Skeet
+(skeet@pobox.com) based on the work of many talented people.
+
+For more information about this port, visit its homepage:
+http://protobuf-csharp-port.googlecode.com
+
+For more information about Protocol Buffers in general, visit the project page 
+for the C++, Java and Python project:
+http://protobuf.googlecode.com
+===============================================================================
+RELEASE NOTES - Version TBD
+===============================================================================
+
+(PENDING MERGE)
+- Issue 20:	Support for decorating classes [Serializable]
+- Issue 22:	Reusable Builder classes
+- Issue 24:	Support for using Json/Xml formats with ICodedInputStream
+
+Features:
+- Added option service_generator_type to control service generation with
+  NONE, GENERIC, INTERFACE, or IRPCDISPATCH
+- Added interfaces IRpcDispatch and IRpcServerStub to provide for blocking
+  services and implementations.
+- Added ProtoGen.exe command-line argument "--protoc_dir=" to specify the 
+  location of protoc.exe.
+- Extracted interfaces for ICodedInputStream and ICodedOutputStream to allow
+  custom implementation of writers with both speed and size optimizations.
+- Addition of the "Google.ProtoBuffers.Serialization" assembly to support
+  reading and writing messages to/from XML, JSON, IDictionary<,> and others.
+- Several performance related fixes and tweeks
+- Issue 3:	Add option to mark generated code with attribute
+- Issue 21:	Decorate fields with [deprecated=true] as [System.Obsolete]
+
+Fixes:
+- Issue 13:	Message with Field same name as message causes uncompilable .cs
+- Issue 16:	Does not integrate well with other tooling
+- Issue 19:	Support for negative enum values
+- Issue 26:	AddRange in GeneratedBuilder iterates twice.
+- Issue 27:	Remove XML documentation output from test projects to clear 
+  warnings/errors.
+- Big-endian support for float, and double on Silverlight
+- Packed and Unpacked parsing allow for all repeated, as per version 2.3
+- Fix for leaving Builder a public ctor on internal classes for use with
+  generic "where T: new()" constraints.
+
+Other:
+- Reformatted all code and line-endings to C# defaults
+- Reworking of performance benchmarks to produce reliable results, option /v2
+
+===============================================================================
+RELEASE NOTES - Version 2.3.0.277
+===============================================================================
+
+Features:
+- Added cls_compliance option to generate attributes indicating 
+  non-CLS-compliance.
+- Added file_extension option to control the generated output file's extension.
+- Added umbrella_namespace option to place the umbrella class into a nested
+  namespace to address issues with proto files having the same name as a 
+  message it contains.
+- Added output_directory option to set the output path for the source file(s).
+- Added ignore_google_protobuf option to avoid generating code for includes 
+  from the google.protobuf package.
+- Added the LITE framework (Google.ProtoBuffersLite.dll) and the ability to
+  generate code with "option optimize_for = LITE_RUNTIME;".
+- Added ability to invoke protoc.exe from within ProtoGen.exe.
+- Upgraded to protoc.exe (2.3) compiler.
+
+Fixes:
+- Issue 9:	Class cannot be static and sealed error
+- Issue 12:	default value for enumerate fields must be filled out
+
+Other:
+- Rewrite of build using MSBbuild instead of NAnt
+- Moved to NUnit Version 2.2.8.0
+- Changed to using secure .snk for releases
+
+===============================================================================
+RELEASE NOTES - Version 0.9.1
+===============================================================================
+
+Fixes:
+- issue 10:	Incorrect encoding of packed fields when serialized
+
+===============================================================================
+RELEASE NOTES - Version 0.9.0
+===============================================================================
+
+- Initial release
+
+===============================================================================
\ No newline at end of file

build/Build.bat

-@echo off
-SET BUILD_TARGET=%1
-SET BUILD_CONFIG=%2
-
-IF "%BUILD_TARGET%"=="" SET BUILD_TARGET=Rebuild
-IF "%BUILD_CONFIG%"=="" SET BUILD_CONFIG=Debug
-
-CMD.exe /Q /C "CD %~dp0 && %WINDIR%\Microsoft.NET\Framework\v4.0.30319\MSBuild.exe build.csproj %3 %4 %5 %6 /t:%BUILD_TARGET% /p:BuildConfiguration=%BUILD_CONFIG% /p:Platform="Any CPU" /p:BuildTools=4.0 /toolsversion:4.0"
-
+@echo off
+SET BUILD_TARGET=%1
+SET BUILD_CONFIG=%2
+
+IF "%BUILD_TARGET%"=="" SET BUILD_TARGET=Rebuild
+IF "%BUILD_CONFIG%"=="" SET BUILD_CONFIG=Debug
+
+CMD.exe /Q /C "CD %~dp0 && %WINDIR%\Microsoft.NET\Framework\v4.0.30319\MSBuild.exe build.csproj %3 %4 %5 %6 /t:%BUILD_TARGET% /p:BuildConfiguration=%BUILD_CONFIG% /p:Platform="Any CPU" /p:BuildTools=4.0 /toolsversion:4.0"
+
 pause
\ No newline at end of file

build/BuildAll.bat

-@ECHO OFF
-
-SET PREV_WORKING_DIR=%CD%
-CD %~dp0
-
-REM -- 3.5 Debug build, ensure this continues to work
-%WINDIR%\Microsoft.NET\Framework\v3.5\MSBuild.exe build.csproj /t:Rebuild /p:BuildConfiguration=Debug /p:Platform="Any CPU" /p:BuildTools=3.5 /toolsversion:3.5"
-IF ERRORLEVEL 1 GOTO ERROR
-
-REM -- 4.0 Debug build
-%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:Rebuild /p:BuildConfiguration=Debug /p:Platform="Any CPU"
-IF ERRORLEVEL 1 GOTO ERROR
-
-REM -- 4.0 Release build
-%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:Rebuild /p:BuildConfiguration=Release /p:Platform="Any CPU"
-IF ERRORLEVEL 1 GOTO ERROR
-
-IF EXIST "%ProgramFiles%\MSBuild\Microsoft\Silverlight\v2.0\Microsoft.Silverlight.CSharp.targets" GOTO SILVERLIGHT
-IF EXIST "%ProgramFiles(x86)%\MSBuild\Microsoft\Silverlight\v2.0\Microsoft.Silverlight.CSharp.targets" GOTO SILVERLIGHT
-
-ECHO Unable to locate %ProgramFiles(x86)%\MSBuild\Microsoft\Silverlight\v2.0
-GOTO ERROR
-
-:SILVERLIGHT
-
-REM -- 4.0 Debug_Silverlight2 build
-%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:Rebuild /p:BuildConfiguration=Debug_Silverlight2 /p:Platform="Any CPU"
-IF ERRORLEVEL 1 GOTO ERROR
-
-REM -- 4.0 Release_Silverlight2 build
-%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:Rebuild /p:BuildConfiguration=Release_Silverlight2 /p:Platform="Any CPU"
-IF ERRORLEVEL 1 GOTO ERROR
-
-GOTO END
-
-:ERROR
-CD %PREV_WORKING_DIR%
-PAUSE
-
-:END
-CD %PREV_WORKING_DIR%
+@ECHO OFF
+
+SET PREV_WORKING_DIR=%CD%
+CD %~dp0
+
+REM -- 3.5 Debug build, ensure this continues to work
+%WINDIR%\Microsoft.NET\Framework\v3.5\MSBuild.exe build.csproj /t:Rebuild /p:BuildConfiguration=Debug /p:Platform="Any CPU" /p:BuildTools=3.5 /toolsversion:3.5"
+IF ERRORLEVEL 1 GOTO ERROR
+
+REM -- 4.0 Debug build
+%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:Rebuild /p:BuildConfiguration=Debug /p:Platform="Any CPU"
+IF ERRORLEVEL 1 GOTO ERROR
+
+REM -- 4.0 Release build
+%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:Rebuild /p:BuildConfiguration=Release /p:Platform="Any CPU"
+IF ERRORLEVEL 1 GOTO ERROR
+
+IF EXIST "%ProgramFiles%\MSBuild\Microsoft\Silverlight\v2.0\Microsoft.Silverlight.CSharp.targets" GOTO SILVERLIGHT
+IF EXIST "%ProgramFiles(x86)%\MSBuild\Microsoft\Silverlight\v2.0\Microsoft.Silverlight.CSharp.targets" GOTO SILVERLIGHT
+
+ECHO Unable to locate %ProgramFiles(x86)%\MSBuild\Microsoft\Silverlight\v2.0
+GOTO ERROR
+
+:SILVERLIGHT
+
+REM -- 4.0 Debug_Silverlight2 build
+%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:Rebuild /p:BuildConfiguration=Debug_Silverlight2 /p:Platform="Any CPU"
+IF ERRORLEVEL 1 GOTO ERROR
+
+REM -- 4.0 Release_Silverlight2 build
+%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:Rebuild /p:BuildConfiguration=Release_Silverlight2 /p:Platform="Any CPU"
+IF ERRORLEVEL 1 GOTO ERROR
+
+GOTO END
+
+:ERROR
+CD %PREV_WORKING_DIR%
+PAUSE
+
+:END
+CD %PREV_WORKING_DIR%
 SET PREV_WORKING_DIR=
\ No newline at end of file

build/BuildSilverlight2.bat

-@echo off
-
-%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:Build /p:BuildConfiguration=Debug_Silverlight2 /p:Platform="Any CPU"
-
+@echo off
+
+%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:Build /p:BuildConfiguration=Debug_Silverlight2 /p:Platform="Any CPU"
+
 pause
\ No newline at end of file

build/GenerateCompletePackage.bat

-@ECHO OFF
-%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:PrepareOutputDirectory
-IF ERRORLEVEL 1 GOTO END
-
-%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:Rebuild;PreparePackageComponent /p:BuildConfiguration=Debug /p:Platform="Any CPU" %PROTOBUF_KEY_FILE%
-IF ERRORLEVEL 1 GOTO END
-
-%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:Rebuild;PreparePackageComponent /p:BuildConfiguration=Debug_Silverlight2 /p:Platform="Any CPU" %PROTOBUF_KEY_FILE%
-IF ERRORLEVEL 1 GOTO END
-
-%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:Rebuild;PreparePackageComponent /p:BuildConfiguration=Release /p:Platform="Any CPU" %PROTOBUF_KEY_FILE%
-IF ERRORLEVEL 1 GOTO END
-
-%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:Rebuild;PreparePackageComponent /p:BuildConfiguration=Release_Silverlight2 /p:Platform="Any CPU" %PROTOBUF_KEY_FILE%
-IF ERRORLEVEL 1 GOTO END
-
-%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:GeneratePackage /p:PackageName=AllBinariesAndSource.zip /p:Platform="Any CPU"
-
+@ECHO OFF
+%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:PrepareOutputDirectory
+IF ERRORLEVEL 1 GOTO END
+
+%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:Rebuild;PreparePackageComponent /p:BuildConfiguration=Debug /p:Platform="Any CPU" %PROTOBUF_KEY_FILE%
+IF ERRORLEVEL 1 GOTO END
+
+%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:Rebuild;PreparePackageComponent /p:BuildConfiguration=Debug_Silverlight2 /p:Platform="Any CPU" %PROTOBUF_KEY_FILE%
+IF ERRORLEVEL 1 GOTO END
+
+%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:Rebuild;PreparePackageComponent /p:BuildConfiguration=Release /p:Platform="Any CPU" %PROTOBUF_KEY_FILE%
+IF ERRORLEVEL 1 GOTO END
+
+%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:Rebuild;PreparePackageComponent /p:BuildConfiguration=Release_Silverlight2 /p:Platform="Any CPU" %PROTOBUF_KEY_FILE%
+IF ERRORLEVEL 1 GOTO END
+
+%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:GeneratePackage /p:PackageName=AllBinariesAndSource.zip /p:Platform="Any CPU"
+
 :END
\ No newline at end of file

build/GenerateReleasePackage.bat

-@ECHO OFF
-%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:PrepareOutputDirectory
-IF ERRORLEVEL 1 GOTO END
-
-%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:Rebuild;PreparePackageComponent /p:BuildConfiguration=Release /p:Platform="Any CPU" %PROTOBUF_KEY_FILE%
-IF ERRORLEVEL 1 GOTO END
-
-%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:Rebuild;PreparePackageComponent /p:BuildConfiguration=Release_Silverlight2 /p:Platform="Any CPU" %PROTOBUF_KEY_FILE%
-IF ERRORLEVEL 1 GOTO END
-
-%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:GeneratePackage /p:PackageName=ReleaseBinaries.zip /p:Platform="Any CPU"
-
+@ECHO OFF
+%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:PrepareOutputDirectory
+IF ERRORLEVEL 1 GOTO END
+
+%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:Rebuild;PreparePackageComponent /p:BuildConfiguration=Release /p:Platform="Any CPU" %PROTOBUF_KEY_FILE%
+IF ERRORLEVEL 1 GOTO END
+
+%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:Rebuild;PreparePackageComponent /p:BuildConfiguration=Release_Silverlight2 /p:Platform="Any CPU" %PROTOBUF_KEY_FILE%
+IF ERRORLEVEL 1 GOTO END
+
+%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild build.csproj /m /t:GeneratePackage /p:PackageName=ReleaseBinaries.zip /p:Platform="Any CPU"
+
 :END
\ No newline at end of file

build/RunBenchmarks.bat

-@echo off
-
-%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild %~dp0\build.csproj /m /t:RunBenchmarks /p:BuildConfiguration=Release /p:Platform="Any CPU"
-
+@echo off
+
+%WINDIR%\Microsoft.NET\Framework\v4.0.30319\msbuild %~dp0\build.csproj /m /t:RunBenchmarks /p:BuildConfiguration=Release /p:Platform="Any CPU"
+
 pause
\ No newline at end of file

build/build35.bat

-@echo off
-SET BUILD_TARGET=%1
-SET BUILD_CONFIG=%2
-
-IF "%BUILD_TARGET%"=="" SET BUILD_TARGET=Rebuild
-IF "%BUILD_CONFIG%"=="" SET BUILD_CONFIG=Debug
-
-CMD.exe /Q /C "CD %~dp0 && %WINDIR%\Microsoft.NET\Framework\v3.5\MSBuild.exe build.csproj %3 %4 %5 %6 /t:%BUILD_TARGET% /p:BuildConfiguration=%BUILD_CONFIG% /p:Platform="Any CPU" /p:BuildTools=3.5 /toolsversion:3.5"
+@echo off
+SET BUILD_TARGET=%1
+SET BUILD_CONFIG=%2
+
+IF "%BUILD_TARGET%"=="" SET BUILD_TARGET=Rebuild
+IF "%BUILD_CONFIG%"=="" SET BUILD_CONFIG=Debug
+
+CMD.exe /Q /C "CD %~dp0 && %WINDIR%\Microsoft.NET\Framework\v3.5\MSBuild.exe build.csproj %3 %4 %5 %6 /t:%BUILD_TARGET% /p:BuildConfiguration=%BUILD_CONFIG% /p:Platform="Any CPU" /p:BuildTools=3.5 /toolsversion:3.5"

license.txt

-Protocol Buffers - Google's data interchange format
-Copyright 2008-2010 Google Inc.  All rights reserved.
-http://github.com/jskeet/dotnet-protobufs/
-Original C++/Java/Python code:
-http://code.google.com/p/protobuf/
-
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are
-met:
-
-    * Redistributions of source code must retain the above copyright
-notice, this list of conditions and the following disclaimer.
-    * Redistributions in binary form must reproduce the above
-copyright notice, this list of conditions and the following disclaimer
-in the documentation and/or other materials provided with the
-distribution.
-    * Neither the name of Google Inc. nor the names of its
-contributors may be used to endorse or promote products derived from
-this software without specific prior written permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+Protocol Buffers - Google's data interchange format
+Copyright 2008-2010 Google Inc.  All rights reserved.
+http://github.com/jskeet/dotnet-protobufs/
+Original C++/Java/Python code:
+http://code.google.com/p/protobuf/
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+    * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+    * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

protos/extest/unittest_extras_lite.proto

-// Additional options required for C# generation. File from copyright
-// line onwards is as per original distribution.
-import "google/protobuf/csharp_options.proto";
-option (google.protobuf.csharp_file_options).namespace = "Google.ProtocolBuffers.TestProtos";
-option (google.protobuf.csharp_file_options).umbrella_classname = "UnitTestExtrasLiteProtoFile";
-
-package protobuf_unittest_extra;
-
-option optimize_for = LITE_RUNTIME;
-
-option java_package = "com.google.protobuf";
-
-message TestRequiredLite {
-  required int32 d = 1;
-  required ExtraEnum en = 2 [default = DEFAULT];
-}
-
-enum ExtraEnum {
-  DEFAULT = 10;
-  EXLITE_FOO = 7;
-  EXLITE_BAR = 8;
-  EXLITE_BAZ = 9;
-}
-
-message TestInteropPersonLite {
-  required string name = 1;
-  required int32 id = 2;
-  optional string email = 3;
-  repeated int32 codes = 10 [packed=true];
-
-  enum PhoneType {
-    MOBILE = 0;
-    HOME = 1;
-    WORK = 2;
-  }
-
-  message PhoneNumber {
-    required string number = 1;
-    optional PhoneType type = 2 [default = HOME];
-  }
-
-  repeated PhoneNumber phone = 4;
-  
-  repeated group Addresses = 5 {
-    required string address = 1;
-    optional string address2 = 2;
-    required string city = 3;
-    required string state = 4;
-    required fixed32 zip = 5;
-  }
-
-  extensions 100 to 199;
-}
-
-message  TestInteropEmployeeIdLite {
-  required string number = 1;
-}
-  
-extend TestInteropPersonLite {
-  required TestInteropEmployeeIdLite employee_id_lite = 126;
-}
+// Additional options required for C# generation. File from copyright
+// line onwards is as per original distribution.
+import "google/protobuf/csharp_options.proto";
+option (google.protobuf.csharp_file_options).namespace = "Google.ProtocolBuffers.TestProtos";
+option (google.protobuf.csharp_file_options).umbrella_classname = "UnitTestExtrasLiteProtoFile";
+option (google.protobuf.csharp_file_options).add_serializable = true;
+
+package protobuf_unittest_extra;
+
+option optimize_for = LITE_RUNTIME;
+
+option java_package = "com.google.protobuf";
+
+message TestRequiredLite {
+  required int32 d = 1;
+  required ExtraEnum en = 2 [default = DEFAULT];
+}
+
+enum ExtraEnum {
+  DEFAULT = 10;
+  EXLITE_FOO = 7;
+  EXLITE_BAR = 8;
+  EXLITE_BAZ = 9;
+}
+
+message TestInteropPersonLite {
+  required string name = 1;
+  required int32 id = 2;
+  optional string email = 3;
+  repeated int32 codes = 10 [packed=true];
+
+  enum PhoneType {
+    MOBILE = 0;
+    HOME = 1;
+    WORK = 2;
+  }
+
+  message PhoneNumber {
+    required string number = 1;
+    optional PhoneType type = 2 [default = HOME];
+  }
+
+  repeated PhoneNumber phone = 4;
+  
+  repeated group Addresses = 5 {
+    required string address = 1;
+    optional string address2 = 2;
+    required string city = 3;
+    required string state = 4;
+    required fixed32 zip = 5;
+  }
+
+  extensions 100 to 199;
+}
+
+message  TestInteropEmployeeIdLite {
+  required string number = 1;
+}
+  
+extend TestInteropPersonLite {
+  required TestInteropEmployeeIdLite employee_id_lite = 126;
+}

protos/extest/unittest_extras_xmltest.proto

 import "google/protobuf/csharp_options.proto";
 option (google.protobuf.csharp_file_options).namespace = "Google.ProtocolBuffers.TestProtos";
 option (google.protobuf.csharp_file_options).umbrella_classname = "UnitTestXmlSerializerTestProtoFile";
+option (google.protobuf.csharp_file_options).add_serializable = true;
 
 package protobuf_unittest_extra;
 
 option optimize_for = SPEED;
 
 enum EnumOptions {
-    ONE = 0;
-    TWO = 1;
-    THREE = 2;
+  ONE = 0;
+  TWO = 1;
+  THREE = 2;
 }
 
-message TestXmlChild
-{
-    repeated EnumOptions options = 3;
-    optional bytes binary = 4;
+message TestXmlChild {
+  repeated EnumOptions options = 3;
+  optional bytes binary = 4;
 }
 
 message TestXmlNoFields {
 }
 
 message TestXmlRescursive {
-    optional TestXmlRescursive child = 1;
+  optional TestXmlRescursive child = 1;
 }
 
 message TestXmlMessage {
 
-    optional int64 number = 6;
-    repeated int32 numbers = 2;
-    optional string text = 3;
-    repeated string textlines = 700;
-    optional bool valid = 5;
-    
-    optional TestXmlChild child = 1;
-    repeated group Children = 401 
-    {
-        repeated EnumOptions options = 3;
-        optional bytes binary = 4;
-    }
-
-    extensions 100 to 199;
+  optional int64 number = 6;
+  repeated int32 numbers = 2;
+  optional string text = 3;
+  repeated string textlines = 700;
+  optional bool valid = 5;
+
+  optional TestXmlChild child = 1;
+  repeated group Children = 401 {
+    repeated EnumOptions options = 3;
+    optional bytes binary = 4;
+  }
+
+extensions 100 to 199;
 }
 
 message  TestXmlExtension {
   required int32 number = 1;
 }
-  
+
 extend TestXmlMessage {
   optional EnumOptions extension_enum = 101;
   optional string extension_text = 102;

protos/extest/unittest_issues.proto

@@ -86,3 +86,47 @@ message NumberField {
     optional int32 _01 = 1;
 }
 
+// Issue 28: Circular message dependencies result in null defaults for DefaultInstance
+
+message MyMessageAReferenceB {
+    required MyMessageBReferenceA value = 1;
+}
+
+message MyMessageBReferenceA {
+    required MyMessageAReferenceB value = 1;
+}
+
+// issue 19 - negative enum values
+
+enum NegativeEnum {
+    FiveBelow = -5;
+    MinusOne = -1;
+    Zero = 0;
+}
+
+message NegativeEnumMessage { 
+    optional NegativeEnum value = 1;
+    repeated NegativeEnum values = 2;
+    repeated NegativeEnum packed_values = 3 [packed=true];
+}
+
+// Issue 21: http://code.google.com/p/protobuf-csharp-port/issues/detail?id=21
+// Decorate fields with [deprecated=true] as [System.Obsolete]
+
+message DeprecatedChild {
+}
+
+enum DeprecatedEnum {
+    one = 1;
+}
+
+message DeprecatedFieldsMessage {
+    optional int32 PrimitiveValue = 1 [deprecated = true];
+    repeated int32 PrimitiveArray = 2 [deprecated = true];
+
+    optional DeprecatedChild MessageValue = 3 [deprecated = true];
+    repeated DeprecatedChild MessageArray = 4 [deprecated = true];
+
+    optional DeprecatedEnum EnumValue = 5 [deprecated = true];
+    repeated DeprecatedEnum EnumArray = 6 [deprecated = true];
+}
\ No newline at end of file

protos/google/protobuf/csharp_options.proto

@@ -38,6 +38,9 @@ message CSharpFileOptions {
 
   // Generate attributes indicating non-CLS-compliance
   optional bool cls_compliance = 8 [default = true];
+  
+  // Generate messages/builders with the [Serializable] attribute
+  optional bool add_serializable = 9 [default = false];
 
   // The extension that should be appended to the umbrella_classname when creating files.
   optional string file_extension = 221 [default = ".cs"];

protos/npp.language.xml

+<NotepadPlus>
+<!--
+Defines syntax highlighting for Notepad++.
+1. Install Notepad++ from http://notepad-plus-plus.org
+2. Open Notepad++, from the View menu, select "User-Defined Dialog..."
+3. Click the "Import..." button and select this file
+4. Restart Notepad++
+5. Open and edit any *.proto file
+-->
+    <UserLang name="Proto Buffer" ext="proto">
+        <Settings>
+            <Global caseIgnored="no" />
+            <TreatAsSymbol comment="no" commentLine="yes" />
+            <Prefix words1="no" words2="no" words3="no" words4="yes" />
+        </Settings>
+        <KeywordLists>
+            <Keywords name="Delimiters">[00]00</Keywords>
+            <Keywords name="Folder+">{</Keywords>
+            <Keywords name="Folder-">}</Keywords>
+            <Keywords name="Operators">=</Keywords>
+            <Keywords name="Comment"> 1option 1package 1import 2; 0//</Keywords>
+            <Keywords name="Words1">message enum service extend</Keywords>
+            <Keywords name="Words2">required optional repeated extensions to rpc returns</Keywords>
+            <Keywords name="Words3">double float int32 int64 uint32 uint64 sint32 sint64 fixed32 fixed64 sfixed32 sfixed64 bool string bytes</Keywords>
+            <Keywords name="Words4"></Keywords>
+        </KeywordLists>
+        <Styles>
+            <WordsStyle name="DEFAULT" styleID="11" fgColor="000000" bgColor="FFFFFF" fontStyle="0" />
+            <WordsStyle name="FOLDEROPEN" styleID="12" fgColor="000000" bgColor="FFFFFF" fontStyle="1" />
+            <WordsStyle name="FOLDERCLOSE" styleID="13" fgColor="000000" bgColor="FFFFFF" fontStyle="1" />
+            <WordsStyle name="KEYWORD1" styleID="5" fgColor="0000FF" bgColor="FFFFFF" fontStyle="0" />
+            <WordsStyle name="KEYWORD2" styleID="6" fgColor="0080C0" bgColor="FFFFFF" fontStyle="0" />
+            <WordsStyle name="KEYWORD3" styleID="7" fgColor="0000FF" bgColor="FFFFFF" fontStyle="0" />
+            <WordsStyle name="KEYWORD4" styleID="8" fgColor="008040" bgColor="FFFFFF" fontStyle="0" />
+            <WordsStyle name="COMMENT" styleID="1" fgColor="008000" bgColor="FFFFFF" fontStyle="0" />
+            <WordsStyle name="COMMENT LINE" styleID="2" fgColor="949494" bgColor="FFFFFF" fontStyle="0" />
+            <WordsStyle name="NUMBER" styleID="4" fgColor="FF0000" bgColor="FFFFFF" fontStyle="0" />
+            <WordsStyle name="OPERATOR" styleID="10" fgColor="000000" bgColor="FFFFFF" fontStyle="0" />
+            <WordsStyle name="DELIMINER1" styleID="14" fgColor="800080" bgColor="FFFFFF" fontStyle="0" />
+            <WordsStyle name="DELIMINER2" styleID="15" fgColor="808080" bgColor="FFFFFF" fontStyle="0" />
+            <WordsStyle name="DELIMINER3" styleID="16" fgColor="000000" bgColor="FFFFFF" fontStyle="0" />
+        </Styles>
+    </UserLang>
+</NotepadPlus>

readme.txt

-Welcome to the C# port of Google Protocol Buffers, written by Jon Skeet
-(skeet@pobox.com) based on the work of many talented people.
-
-For more information about this port, visit its homepage:
-http://protobuf-csharp-port.googlecode.com
-
-For more information about Protocol Buffers in general, visit the
-project page for the C++, Java and Python project:
-http://protobuf.googlecode.com
-
-
-Release 0.9.1
--------------
-
-Fix to release 0.9:
-
-- Include protos in binary download
-- Fix issue 10: incorrect encoding of packed fields when serialized
-  size wasn't fetched first
-
-
-Release 0.9
------------
-
-Due to popular demand, I have built a version of the binaries to put
-on the web site. Currently these are set at assembly version 0.9,
-and an assembly file version of 0.9. This should be seen as a mark
-of the readiness of the release process more than the stability of
-the code. As far as I'm aware, the code itself is perfectly fine: I
-certainly have plans for more features particularly around making
-code generation simpler, but you should feel confident about the
-parsing and serialization of messages produced with this version of
-the library. Of course, if you do find any problems, *please* report
-them at the web site.
-
-Currently the downloadable release is built with the snk file which
-is in the open source library. I am considering having a privately
-held key so that you can check that you're building against a
-"blessed" release - feedback on this (and any other aspect of the
-release process) is very welcome.

src/ProtoGen.Test/DependencyResolutionTest.cs

@@ -52,7 +52,7 @@ namespace Google.ProtocolBuffers.ProtoGen
         {
             FileDescriptorProto first = new FileDescriptorProto.Builder {Name = "First"}.Build();
             FileDescriptorProto second = new FileDescriptorProto.Builder {Name = "Second"}.Build();
-            FileDescriptorSet set = new FileDescriptorSet {FileList = {first, second}};
+            FileDescriptorSet set = new FileDescriptorSet.Builder { FileList = { first, second } }.Build();
 
             IList<FileDescriptor> converted = Generator.ConvertDescriptors(CSharpFileOptions.DefaultInstance, set);
             Assert.AreEqual(2, converted.Count);
@@ -68,7 +68,7 @@ namespace Google.ProtocolBuffers.ProtoGen
             FileDescriptorProto first =
                 new FileDescriptorProto.Builder {Name = "First", DependencyList = {"Second"}}.Build();
             FileDescriptorProto second = new FileDescriptorProto.Builder {Name = "Second"}.Build();
-            FileDescriptorSet set = new FileDescriptorSet {FileList = {first, second}};
+            FileDescriptorSet set = new FileDescriptorSet.Builder { FileList = { first, second } }.Build();
             IList<FileDescriptor> converted = Generator.ConvertDescriptors(CSharpFileOptions.DefaultInstance, set);
             Assert.AreEqual(2, converted.Count);
             Assert.AreEqual("First", converted[0].Name);
@@ -84,7 +84,7 @@ namespace Google.ProtocolBuffers.ProtoGen
             FileDescriptorProto first = new FileDescriptorProto.Builder {Name = "First"}.Build();
             FileDescriptorProto second =
                 new FileDescriptorProto.Builder {Name = "Second", DependencyList = {"First"}}.Build();
-            FileDescriptorSet set = new FileDescriptorSet {FileList = {first, second}};
+            FileDescriptorSet set = new FileDescriptorSet.Builder { FileList = { first, second } }.Build();
             IList<FileDescriptor> converted = Generator.ConvertDescriptors(CSharpFileOptions.DefaultInstance, set);
             Assert.AreEqual(2, converted.Count);
             Assert.AreEqual("First", converted[0].Name);
@@ -101,7 +101,7 @@ namespace Google.ProtocolBuffers.ProtoGen
                 new FileDescriptorProto.Builder {Name = "First", DependencyList = {"Second"}}.Build();
             FileDescriptorProto second =
                 new FileDescriptorProto.Builder {Name = "Second", DependencyList = {"First"}}.Build();
-            FileDescriptorSet set = new FileDescriptorSet {FileList = {first, second}};
+            FileDescriptorSet set = new FileDescriptorSet.Builder { FileList = { first, second } }.Build();
             try
             {
                 Generator.ConvertDescriptors(CSharpFileOptions.DefaultInstance, set);
@@ -118,7 +118,7 @@ namespace Google.ProtocolBuffers.ProtoGen
         {
             FileDescriptorProto first =
                 new FileDescriptorProto.Builder {Name = "First", DependencyList = {"Second"}}.Build();
-            FileDescriptorSet set = new FileDescriptorSet {FileList = {first}};
+            FileDescriptorSet set = new FileDescriptorSet.Builder { FileList = { first } }.Build();
             try
             {
                 Generator.ConvertDescriptors(CSharpFileOptions.DefaultInstance, set);
@@ -135,7 +135,7 @@ namespace Google.ProtocolBuffers.ProtoGen
         {
             FileDescriptorProto first =
                 new FileDescriptorProto.Builder {Name = "First", DependencyList = {"First"}}.Build();
-            FileDescriptorSet set = new FileDescriptorSet {FileList = {first}};
+            FileDescriptorSet set = new FileDescriptorSet.Builder { FileList = { first } }.Build();
             try
             {
                 Generator.ConvertDescriptors(CSharpFileOptions.DefaultInstance, set);

src/ProtoGen/EnumFieldGenerator.cs

@@ -49,10 +49,11 @@ namespace Google.ProtocolBuffers.ProtoGen
         {
             writer.WriteLine("private bool has{0};", PropertyName);
             writer.WriteLine("private {0} {1}_ = {2};", TypeName, Name, DefaultValue);
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public bool Has{0} {{", PropertyName);
             writer.WriteLine("  get {{ return has{0}; }}", PropertyName);
             writer.WriteLine("}");
-            AddClsComplianceCheck(writer);
+            AddPublicMemberAttributes(writer);
             writer.WriteLine("public {0} {1} {{", TypeName, PropertyName);
             writer.WriteLine("  get {{ return {0}_; }}", Name);
             writer.WriteLine("}");
@@ -60,21 +61,25 @@ namespace Google.ProtocolBuffers.ProtoGen
 
         public void GenerateBuilderMembers(TextGenerator writer)
         {
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public bool Has{0} {{", PropertyName);
             writer.WriteLine(" get {{ return result.has{0}; }}", PropertyName);
             writer.WriteLine("}");
-            AddClsComplianceCheck(writer);
+            AddPublicMemberAttributes(writer);
             writer.WriteLine("public {0} {1} {{", TypeName, PropertyName);
             writer.WriteLine("  get {{ return result.{0}; }}", PropertyName);
             writer.WriteLine("  set {{ Set{0}(value); }}", PropertyName);
             writer.WriteLine("}");
-            AddClsComplianceCheck(writer);
+            AddPublicMemberAttributes(writer);
             writer.WriteLine("public Builder Set{0}({1} value) {{", PropertyName, TypeName);
+            writer.WriteLine("  PrepareBuilder();");
             writer.WriteLine("  result.has{0} = true;", PropertyName);
             writer.WriteLine("  result.{0}_ = value;", Name);
             writer.WriteLine("  return this;");
             writer.WriteLine("}");
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public Builder Clear{0}() {{", PropertyName);
+            writer.WriteLine("  PrepareBuilder();");
             writer.WriteLine("  result.has{0} = false;", PropertyName);
             writer.WriteLine("  result.{0}_ = {1};", Name, DefaultValue);
             writer.WriteLine("  return this;");

src/ProtoGen/FieldGeneratorBase.cs

@@ -251,6 +251,12 @@ namespace Google.ProtocolBuffers.ProtoGen
             }
         }
 
+        protected void AddPublicMemberAttributes(TextGenerator writer)
+        {
+            AddDeprecatedFlag(writer);
+            AddClsComplianceCheck(writer);
+        }
+
         protected void AddClsComplianceCheck(TextGenerator writer)
         {
             if (!Descriptor.IsCLSCompliant && Descriptor.File.CSharpOptions.ClsCompliance)
@@ -259,6 +265,19 @@ namespace Google.ProtocolBuffers.ProtoGen
             }
         }
 
+        protected bool IsObsolete { get { return Descriptor.Options.Deprecated; } }
+
+        /// <summary>
+        /// Writes [global::System.ObsoleteAttribute()] if the member is obsolete
+        /// </summary>
+        protected void AddDeprecatedFlag(TextGenerator writer)
+        {
+            if (IsObsolete)
+            {
+                writer.WriteLine("[global::System.ObsoleteAttribute()]");
+            }
+        }
+
         /// <summary>
         /// For encodings with fixed sizes, returns that size in bytes.  Otherwise
         /// returns -1. TODO(jonskeet): Make this less ugly.

src/ProtoGen/MessageFieldGenerator.cs

@@ -48,38 +48,48 @@ namespace Google.ProtocolBuffers.ProtoGen
         public void GenerateMembers(TextGenerator writer)
         {
             writer.WriteLine("private bool has{0};", PropertyName);
-            writer.WriteLine("private {0} {1}_ = {2};", TypeName, Name, DefaultValue);
+            writer.WriteLine("private {0} {1}_;", TypeName, Name);
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public bool Has{0} {{", PropertyName);
             writer.WriteLine("  get {{ return has{0}; }}", PropertyName);
             writer.WriteLine("}");
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public {0} {1} {{", TypeName, PropertyName);
-            writer.WriteLine("  get {{ return {0}_; }}", Name);
+            writer.WriteLine("  get {{ return {0}_ ?? {1}; }}", Name, DefaultValue);
             writer.WriteLine("}");
         }
 
         public void GenerateBuilderMembers(TextGenerator writer)
         {
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public bool Has{0} {{", PropertyName);
             writer.WriteLine(" get {{ return result.has{0}; }}", PropertyName);
             writer.WriteLine("}");
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public {0} {1} {{", TypeName, PropertyName);
             writer.WriteLine("  get {{ return result.{0}; }}", PropertyName);
             writer.WriteLine("  set {{ Set{0}(value); }}", PropertyName);
             writer.WriteLine("}");
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public Builder Set{0}({1} value) {{", PropertyName, TypeName);
             AddNullCheck(writer);
+            writer.WriteLine("  PrepareBuilder();");
             writer.WriteLine("  result.has{0} = true;", PropertyName);
             writer.WriteLine("  result.{0}_ = value;", Name);
             writer.WriteLine("  return this;");
             writer.WriteLine("}");
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public Builder Set{0}({1}.Builder builderForValue) {{", PropertyName, TypeName);
             AddNullCheck(writer, "builderForValue");
+            writer.WriteLine("  PrepareBuilder();");
             writer.WriteLine("  result.has{0} = true;", PropertyName);
             writer.WriteLine("  result.{0}_ = builderForValue.Build();", Name);
             writer.WriteLine("  return this;");
             writer.WriteLine("}");
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public Builder Merge{0}({1} value) {{", PropertyName, TypeName);
             AddNullCheck(writer);
+            writer.WriteLine("  PrepareBuilder();");
             writer.WriteLine("  if (result.has{0} &&", PropertyName);
             writer.WriteLine("      result.{0}_ != {1}) {{", Name, DefaultValue);
             writer.WriteLine("      result.{0}_ = {1}.CreateBuilder(result.{0}_).MergeFrom(value).BuildPartial();", Name,
@@ -90,9 +100,11 @@ namespace Google.ProtocolBuffers.ProtoGen
             writer.WriteLine("  result.has{0} = true;", PropertyName);
             writer.WriteLine("  return this;");
             writer.WriteLine("}");
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public Builder Clear{0}() {{", PropertyName);
+            writer.WriteLine("  PrepareBuilder();");
             writer.WriteLine("  result.has{0} = false;", PropertyName);
-            writer.WriteLine("  result.{0}_ = {1};", Name, DefaultValue);
+            writer.WriteLine("  result.{0}_ = null;", Name);
             writer.WriteLine("  return this;");
             writer.WriteLine("}");
         }

src/ProtoGen/MessageGenerator.cs

@@ -165,9 +165,13 @@ namespace Google.ProtocolBuffers.ProtoGen
         {
             return SourceGenerators.CreateFieldGenerator(fieldDescriptor, FieldOrdinal(fieldDescriptor));
         }
-
+        
         public void Generate(TextGenerator writer)
         {
+            if (Descriptor.File.CSharpOptions.AddSerializable)
+            {
+                writer.WriteLine("[global::System.SerializableAttribute()]");
+            }
             writer.WriteLine("[global::System.Diagnostics.DebuggerNonUserCodeAttribute()]");
             writer.WriteLine("[global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()]");
             writer.WriteLine("[global::System.CodeDom.Compiler.GeneratedCodeAttribute(\"{0}\", \"{1}\")]",
@@ -177,8 +181,9 @@ namespace Google.ProtocolBuffers.ProtoGen
                              Descriptor.Proto.ExtensionRangeCount > 0 ? "Extendable" : "Generated",
                              RuntimeSuffix);
             writer.Indent();
+            writer.WriteLine("private {0}() {{ }}", ClassName);
             // Must call BuildPartial() to make sure all lists are made read-only
-            writer.WriteLine("private static readonly {0} defaultInstance = new Builder().BuildPartial();", ClassName);
+            writer.WriteLine("private static readonly {0} defaultInstance = new {0}().MakeReadOnly();", ClassName);
 
             if (OptimizeSpeed)
             {
@@ -199,7 +204,7 @@ namespace Google.ProtocolBuffers.ProtoGen
             writer.WriteLine("}");
             writer.WriteLine();
             writer.WriteLine("public override {0} DefaultInstanceForType {{", ClassName);
-            writer.WriteLine("  get { return defaultInstance; }");
+            writer.WriteLine("  get { return DefaultInstance; }");
             writer.WriteLine("}");
             writer.WriteLine();
             writer.WriteLine("protected override {0} ThisMessage {{", ClassName);
@@ -547,13 +552,28 @@ namespace Google.ProtocolBuffers.ProtoGen
 
         private void GenerateBuilder(TextGenerator writer)
         {
+            writer.WriteLine("private {0} MakeReadOnly() {{", ClassName);
+            writer.Indent();
+            foreach (FieldDescriptor field in Descriptor.Fields)
+            {
+                CreateFieldGenerator(field).GenerateBuildingCode(writer);
+            }
+            writer.WriteLine("return this;");
+            writer.Outdent();
+            writer.WriteLine("}");
+            writer.WriteLine();
+
             writer.WriteLine("public static Builder CreateBuilder() { return new Builder(); }");
             writer.WriteLine("public override Builder ToBuilder() { return CreateBuilder(this); }");
             writer.WriteLine("public override Builder CreateBuilderForType() { return new Builder(); }");
             writer.WriteLine("public static Builder CreateBuilder({0} prototype) {{", ClassName);
-            writer.WriteLine("  return (Builder) new Builder().MergeFrom(prototype);");
+            writer.WriteLine("  return new Builder(prototype);");
             writer.WriteLine("}");
             writer.WriteLine();
+            if (Descriptor.File.CSharpOptions.AddSerializable)
+            {
+                writer.WriteLine("[global::System.SerializableAttribute()]");
+            }
             writer.WriteLine("[global::System.Diagnostics.DebuggerNonUserCodeAttribute()]");
             writer.WriteLine("[global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()]");
             writer.WriteLine("[global::System.CodeDom.Compiler.GeneratedCodeAttribute(\"{0}\", \"{1}\")]",
@@ -582,21 +602,52 @@ namespace Google.ProtocolBuffers.ProtoGen
 
         private void GenerateCommonBuilderMethods(TextGenerator writer)
         {
-            writer.WriteLine("public Builder() {{}}", ClassAccessLevel);
+            //default constructor
+            writer.WriteLine("public Builder() {");
+            //Durring static initialization of message, DefaultInstance is expected to return null.
+            writer.WriteLine("  result = DefaultInstance;");
+            writer.WriteLine("  resultIsReadOnly = true;");
+            writer.WriteLine("}");
+            //clone constructor
+            writer.WriteLine("internal Builder({0} cloneFrom) {{", ClassName);
+            writer.WriteLine("  result = cloneFrom;");
+            writer.WriteLine("  resultIsReadOnly = true;");
+            writer.WriteLine("}");
+            writer.WriteLine();
+            writer.WriteLine("private bool resultIsReadOnly;");
+            writer.WriteLine("private {0} result;", ClassName);
             writer.WriteLine();
-            writer.WriteLine("{0} result = new {0}();", ClassName);
+            writer.WriteLine("private {0} PrepareBuilder() {{", ClassName);
+            writer.WriteLine("  if (resultIsReadOnly) {");
+            writer.WriteLine("    {0} original = result;", ClassName);
+            writer.WriteLine("    result = new {0}();", ClassName);
+            writer.WriteLine("    resultIsReadOnly = false;");
+            writer.WriteLine("    MergeFrom(original);");
+            writer.WriteLine("  }");
+            writer.WriteLine("  return result;");
+            writer.WriteLine("}");
+            writer.WriteLine();
+            writer.WriteLine("public override bool IsInitialized {");
+            writer.WriteLine("  get { return result.IsInitialized; }");
+            writer.WriteLine("}");
             writer.WriteLine();
             writer.WriteLine("protected override {0} MessageBeingBuilt {{", ClassName);
-            writer.WriteLine("  get { return result; }");
+            writer.WriteLine("  get { return PrepareBuilder(); }");
             writer.WriteLine("}");
             writer.WriteLine();
+            //Not actually expecting that DefaultInstance would ever be null here; however, we will ensure it does not break
             writer.WriteLine("public override Builder Clear() {");
-            writer.WriteLine("  result = new {0}();", ClassName);
+            writer.WriteLine("  result = DefaultInstance;", ClassName);
+            writer.WriteLine("  resultIsReadOnly = true;");
             writer.WriteLine("  return this;");
             writer.WriteLine("}");
             writer.WriteLine();
             writer.WriteLine("public override Builder Clone() {");
-            writer.WriteLine("  return new Builder().MergeFrom(result);");
+            writer.WriteLine("  if (resultIsReadOnly) {");
+            writer.WriteLine("    return new Builder(result);");
+            writer.WriteLine("  } else {");
+            writer.WriteLine("    return new Builder().MergeFrom(result);");
+            writer.WriteLine("  }");
             writer.WriteLine("}");
             writer.WriteLine();
             if (!UseLiteRuntime)
@@ -613,17 +664,11 @@ namespace Google.ProtocolBuffers.ProtoGen
 
             writer.WriteLine("public override {0} BuildPartial() {{", ClassName);
             writer.Indent();
-            writer.WriteLine("if (result == null) {");
-            writer.WriteLine(
-                "  throw new global::System.InvalidOperationException(\"build() has already been called on this Builder\");");
+            writer.WriteLine("if (resultIsReadOnly) {");
+            writer.WriteLine("  return result;");
             writer.WriteLine("}");
-            foreach (FieldDescriptor field in Descriptor.Fields)
-            {
-                CreateFieldGenerator(field).GenerateBuildingCode(writer);
-            }
-            writer.WriteLine("{0} returnMe = result;", ClassName);
-            writer.WriteLine("result = null;");
-            writer.WriteLine("return returnMe;");
+            writer.WriteLine("resultIsReadOnly = true;");
+            writer.WriteLine("return result.MakeReadOnly();");
             writer.Outdent();
             writer.WriteLine("}");
             writer.WriteLine();
@@ -644,6 +689,7 @@ namespace Google.ProtocolBuffers.ProtoGen
                 // fields are set so we can skip the merge.
                 writer.Indent();
                 writer.WriteLine("if (other == {0}.DefaultInstance) return this;", FullClassName);
+                writer.WriteLine("PrepareBuilder();");
                 foreach (FieldDescriptor field in Descriptor.Fields)
                 {
                     CreateFieldGenerator(field).GenerateMergingCode(writer);
@@ -676,6 +722,7 @@ namespace Google.ProtocolBuffers.ProtoGen
             writer.WriteLine(
                 "public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {");
             writer.Indent();
+            writer.WriteLine("PrepareBuilder();");
             if (!UseLiteRuntime)
             {
                 writer.WriteLine("pb::UnknownFieldSet.Builder unknownFields = null;");

src/ProtoGen/PrimitiveFieldGenerator.cs

@@ -50,10 +50,11 @@ namespace Google.ProtocolBuffers.ProtoGen
         {
             writer.WriteLine("private bool has{0};", PropertyName);
             writer.WriteLine("private {0} {1}_{2};", TypeName, Name, HasDefaultValue ? " = " + DefaultValue : "");
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public bool Has{0} {{", PropertyName);
             writer.WriteLine("  get {{ return has{0}; }}", PropertyName);
             writer.WriteLine("}");
-            AddClsComplianceCheck(writer);
+            AddPublicMemberAttributes(writer);
             writer.WriteLine("public {0} {1} {{", TypeName, PropertyName);
             writer.WriteLine("  get {{ return {0}_; }}", Name);
             writer.WriteLine("}");
@@ -61,22 +62,26 @@ namespace Google.ProtocolBuffers.ProtoGen
 
         public void GenerateBuilderMembers(TextGenerator writer)
         {
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public bool Has{0} {{", PropertyName);
             writer.WriteLine("  get {{ return result.has{0}; }}", PropertyName);
             writer.WriteLine("}");
-            AddClsComplianceCheck(writer);
+            AddPublicMemberAttributes(writer);
             writer.WriteLine("public {0} {1} {{", TypeName, PropertyName);
             writer.WriteLine("  get {{ return result.{0}; }}", PropertyName);
             writer.WriteLine("  set {{ Set{0}(value); }}", PropertyName);
             writer.WriteLine("}");
-            AddClsComplianceCheck(writer);
+            AddPublicMemberAttributes(writer);
             writer.WriteLine("public Builder Set{0}({1} value) {{", PropertyName, TypeName);
             AddNullCheck(writer);
+            writer.WriteLine("  PrepareBuilder();");
             writer.WriteLine("  result.has{0} = true;", PropertyName);
             writer.WriteLine("  result.{0}_ = value;", Name);
             writer.WriteLine("  return this;");
             writer.WriteLine("}");
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public Builder Clear{0}() {{", PropertyName);
+            writer.WriteLine("  PrepareBuilder();");
             writer.WriteLine("  result.has{0} = false;", PropertyName);
             writer.WriteLine("  result.{0}_ = {1};", Name, DefaultValue);
             writer.WriteLine("  return this;");

src/ProtoGen/RepeatedEnumFieldGenerator.cs

@@ -52,15 +52,18 @@ namespace Google.ProtocolBuffers.ProtoGen
                 writer.WriteLine("private int {0}MemoizedSerializedSize;", Name);
             }
             writer.WriteLine("private pbc::PopsicleList<{0}> {1}_ = new pbc::PopsicleList<{0}>();", TypeName, Name);
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public scg::IList<{0}> {1}List {{", TypeName, PropertyName);
             writer.WriteLine("  get {{ return pbc::Lists.AsReadOnly({0}_); }}", Name);
             writer.WriteLine("}");
 
             // TODO(jonskeet): Redundant API calls? Possibly - include for portability though. Maybe create an option.
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public int {0}Count {{", PropertyName);
             writer.WriteLine("  get {{ return {0}_.Count; }}", Name);
             writer.WriteLine("}");
 
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public {0} Get{1}(int index) {{", TypeName, PropertyName);
             writer.WriteLine("  return {0}_[index];", Name);
             writer.WriteLine("}");
@@ -70,28 +73,39 @@ namespace Google.ProtocolBuffers.ProtoGen
         {
             // Note:  We can return the original list here, because we make it unmodifiable when we build
             // We return it via IPopsicleList so that collection initializers work more pleasantly.
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public pbc::IPopsicleList<{0}> {1}List {{", TypeName, PropertyName);
-            writer.WriteLine("  get {{ return result.{0}_; }}", Name);
+            writer.WriteLine("  get {{ return PrepareBuilder().{0}_; }}", Name);
             writer.WriteLine("}");
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public int {0}Count {{", PropertyName);
             writer.WriteLine("  get {{ return result.{0}Count; }}", PropertyName);
             writer.WriteLine("}");
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public {0} Get{1}(int index) {{", TypeName, PropertyName);
             writer.WriteLine("  return result.Get{0}(index);", PropertyName);
             writer.WriteLine("}");
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public Builder Set{0}(int index, {1} value) {{", PropertyName, TypeName);
+            writer.WriteLine("  PrepareBuilder();");
             writer.WriteLine("  result.{0}_[index] = value;", Name);
             writer.WriteLine("  return this;");
             writer.WriteLine("}");
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public Builder Add{0}({1} value) {{", PropertyName, TypeName);
+            writer.WriteLine("  PrepareBuilder();");
             writer.WriteLine("  result.{0}_.Add(value);", Name, TypeName);
             writer.WriteLine("  return this;");
             writer.WriteLine("}");
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public Builder AddRange{0}(scg::IEnumerable<{1}> values) {{", PropertyName, TypeName);
-            writer.WriteLine("  base.AddRange(values, result.{0}_);", Name);
+            writer.WriteLine("  PrepareBuilder();");
+            writer.WriteLine("  result.{0}_.Add(values);", Name);
             writer.WriteLine("  return this;");
             writer.WriteLine("}");
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public Builder Clear{0}() {{", PropertyName);
+            writer.WriteLine("  PrepareBuilder();");
             writer.WriteLine("  result.{0}_.Clear();", Name);
             writer.WriteLine("  return this;");
             writer.WriteLine("}");
@@ -100,13 +114,13 @@ namespace Google.ProtocolBuffers.ProtoGen
         public void GenerateMergingCode(TextGenerator writer)
         {
             writer.WriteLine("if (other.{0}_.Count != 0) {{", Name);
-            writer.WriteLine("  base.AddRange(other.{0}_, result.{0}_);", Name);
+            writer.WriteLine("  result.{0}_.Add(other.{0}_);", Name);
             writer.WriteLine("}");
         }
 
         public void GenerateBuildingCode(TextGenerator writer)
         {
-            writer.WriteLine("result.{0}_.MakeReadOnly();", Name);
+            writer.WriteLine("{0}_.MakeReadOnly();", Name);
         }
 
         public void GenerateParsingCode(TextGenerator writer)

src/ProtoGen/RepeatedMessageFieldGenerator.cs

@@ -48,15 +48,18 @@ namespace Google.ProtocolBuffers.ProtoGen
         public void GenerateMembers(TextGenerator writer)
         {
             writer.WriteLine("private pbc::PopsicleList<{0}> {1}_ = new pbc::PopsicleList<{0}>();", TypeName, Name);
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public scg::IList<{0}> {1}List {{", TypeName, PropertyName);
             writer.WriteLine("  get {{ return {0}_; }}", Name);
             writer.WriteLine("}");
 
             // TODO(jonskeet): Redundant API calls? Possibly - include for portability though. Maybe create an option.
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public int {0}Count {{", PropertyName);
             writer.WriteLine("  get {{ return {0}_.Count; }}", Name);
             writer.WriteLine("}");
 
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public {0} Get{1}(int index) {{", TypeName, PropertyName);
             writer.WriteLine("  return {0}_[index];", Name);
             writer.WriteLine("}");
@@ -66,42 +69,57 @@ namespace Google.ProtocolBuffers.ProtoGen
         {
             // Note:  We can return the original list here, because we make it unmodifiable when we build
             // We return it via IPopsicleList so that collection initializers work more pleasantly.
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public pbc::IPopsicleList<{0}> {1}List {{", TypeName, PropertyName);
-            writer.WriteLine("  get {{ return result.{0}_; }}", Name);
+            writer.WriteLine("  get {{ return PrepareBuilder().{0}_; }}", Name);
             writer.WriteLine("}");
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public int {0}Count {{", PropertyName);
             writer.WriteLine("  get {{ return result.{0}Count; }}", PropertyName);
             writer.WriteLine("}");
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public {0} Get{1}(int index) {{", TypeName, PropertyName);
             writer.WriteLine("  return result.Get{0}(index);", PropertyName);
             writer.WriteLine("}");
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public Builder Set{0}(int index, {1} value) {{", PropertyName, TypeName);
             AddNullCheck(writer);
+            writer.WriteLine("  PrepareBuilder();");
             writer.WriteLine("  result.{0}_[index] = value;", Name);
             writer.WriteLine("  return this;");
             writer.WriteLine("}");
             // Extra overload for builder (just on messages)
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public Builder Set{0}(int index, {1}.Builder builderForValue) {{", PropertyName, TypeName);
             AddNullCheck(writer, "builderForValue");
+            writer.WriteLine("  PrepareBuilder();");
             writer.WriteLine("  result.{0}_[index] = builderForValue.Build();", Name);
             writer.WriteLine("  return this;");
             writer.WriteLine("}");
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public Builder Add{0}({1} value) {{", PropertyName, TypeName);
             AddNullCheck(writer);
+            writer.WriteLine("  PrepareBuilder();");
             writer.WriteLine("  result.{0}_.Add(value);", Name, TypeName);
             writer.WriteLine("  return this;");
             writer.WriteLine("}");
             // Extra overload for builder (just on messages)
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public Builder Add{0}({1}.Builder builderForValue) {{", PropertyName, TypeName);
             AddNullCheck(writer, "builderForValue");
+            writer.WriteLine("  PrepareBuilder();");
             writer.WriteLine("  result.{0}_.Add(builderForValue.Build());", Name);
             writer.WriteLine("  return this;");
             writer.WriteLine("}");
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public Builder AddRange{0}(scg::IEnumerable<{1}> values) {{", PropertyName, TypeName);
-            writer.WriteLine("  base.AddRange(values, result.{0}_);", Name);
+            writer.WriteLine("  PrepareBuilder();");
+            writer.WriteLine("  result.{0}_.Add(values);", Name);
             writer.WriteLine("  return this;");
             writer.WriteLine("}");
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public Builder Clear{0}() {{", PropertyName);
+            writer.WriteLine("  PrepareBuilder();");
             writer.WriteLine("  result.{0}_.Clear();", Name);
             writer.WriteLine("  return this;");
             writer.WriteLine("}");
@@ -110,13 +128,13 @@ namespace Google.ProtocolBuffers.ProtoGen
         public void GenerateMergingCode(TextGenerator writer)
         {
             writer.WriteLine("if (other.{0}_.Count != 0) {{", Name);
-            writer.WriteLine("  base.AddRange(other.{0}_, result.{0}_);", Name);
+            writer.WriteLine("  result.{0}_.Add(other.{0}_);", Name);
             writer.WriteLine("}");
         }
 
         public void GenerateBuildingCode(TextGenerator writer)
         {
-            writer.WriteLine("result.{0}_.MakeReadOnly();", Name);
+            writer.WriteLine("{0}_.MakeReadOnly();", Name);
         }
 
         public void GenerateParsingCode(TextGenerator writer)

src/ProtoGen/RepeatedPrimitiveFieldGenerator.cs

@@ -52,17 +52,18 @@ namespace Google.ProtocolBuffers.ProtoGen
                 writer.WriteLine("private int {0}MemoizedSerializedSize;", Name);
             }
             writer.WriteLine("private pbc::PopsicleList<{0}> {1}_ = new pbc::PopsicleList<{0}>();", TypeName, Name);
-            AddClsComplianceCheck(writer);
+            AddPublicMemberAttributes(writer);
             writer.WriteLine("public scg::IList<{0}> {1}List {{", TypeName, PropertyName);
             writer.WriteLine("  get {{ return pbc::Lists.AsReadOnly({0}_); }}", Name);
             writer.WriteLine("}");
 
             // TODO(jonskeet): Redundant API calls? Possibly - include for portability though. Maybe create an option.
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public int {0}Count {{", PropertyName);
             writer.WriteLine("  get {{ return {0}_.Count; }}", Name);
             writer.WriteLine("}");
 
-            AddClsComplianceCheck(writer);
+            AddPublicMemberAttributes(writer);
             writer.WriteLine("public {0} Get{1}(int index) {{", TypeName, PropertyName);
             writer.WriteLine("  return {0}_[index];", Name);
             writer.WriteLine("}");
@@ -72,35 +73,41 @@ namespace Google.ProtocolBuffers.ProtoGen
         {
             // Note:  We can return the original list here, because we make it unmodifiable when we build
             // We return it via IPopsicleList so that collection initializers work more pleasantly.
-            AddClsComplianceCheck(writer);
+            AddPublicMemberAttributes(writer);
             writer.WriteLine("public pbc::IPopsicleList<{0}> {1}List {{", TypeName, PropertyName);
-            writer.WriteLine("  get {{ return result.{0}_; }}", Name);
+            writer.WriteLine("  get {{ return PrepareBuilder().{0}_; }}", Name);
             writer.WriteLine("}");
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public int {0}Count {{", PropertyName);
             writer.WriteLine("  get {{ return result.{0}Count; }}", PropertyName);
             writer.WriteLine("}");
-            AddClsComplianceCheck(writer);
+            AddPublicMemberAttributes(writer);
             writer.WriteLine("public {0} Get{1}(int index) {{", TypeName, PropertyName);
             writer.WriteLine("  return result.Get{0}(index);", PropertyName);
             writer.WriteLine("}");
-            AddClsComplianceCheck(writer);
+            AddPublicMemberAttributes(writer);
             writer.WriteLine("public Builder Set{0}(int index, {1} value) {{", PropertyName, TypeName);
             AddNullCheck(writer);
+            writer.WriteLine("  PrepareBuilder();");
             writer.WriteLine("  result.{0}_[index] = value;", Name);
             writer.WriteLine("  return this;");
             writer.WriteLine("}");
-            AddClsComplianceCheck(writer);
+            AddPublicMemberAttributes(writer);
             writer.WriteLine("public Builder Add{0}({1} value) {{", PropertyName, TypeName);
             AddNullCheck(writer);
+            writer.WriteLine("  PrepareBuilder();");
             writer.WriteLine("  result.{0}_.Add(value);", Name, TypeName);
             writer.WriteLine("  return this;");
             writer.WriteLine("}");
-            AddClsComplianceCheck(writer);
+            AddPublicMemberAttributes(writer);
             writer.WriteLine("public Builder AddRange{0}(scg::IEnumerable<{1}> values) {{", PropertyName, TypeName);
-            writer.WriteLine("  base.AddRange(values, result.{0}_);", Name);
+            writer.WriteLine("  PrepareBuilder();");
+            writer.WriteLine("  result.{0}_.Add(values);", Name);
             writer.WriteLine("  return this;");
             writer.WriteLine("}");
+            AddDeprecatedFlag(writer);
             writer.WriteLine("public Builder Clear{0}() {{", PropertyName);
+            writer.WriteLine("  PrepareBuilder();");
             writer.WriteLine("  result.{0}_.Clear();", Name);
             writer.WriteLine("  return this;");
             writer.WriteLine("}");
@@ -109,13 +116,13 @@ namespace Google.ProtocolBuffers.ProtoGen
         public void GenerateMergingCode(TextGenerator writer)
         {
             writer.WriteLine("if (other.{0}_.Count != 0) {{", Name);
-            writer.WriteLine("  base.AddRange(other.{0}_, result.{0}_);", Name);
+            writer.WriteLine("  result.{0}_.Add(other.{0}_);", Name);
             writer.WriteLine("}");
         }
 
         public void GenerateBuildingCode(TextGenerator writer)
         {
-            writer.WriteLine("result.{0}_.MakeReadOnly();", Name);
+            writer.WriteLine("{0}_.MakeReadOnly();", Name);
         }
 
         public void GenerateParsingCode(TextGenerator writer)

src/ProtoGen/UmbrellaClassGenerator.cs

@@ -138,8 +138,8 @@ namespace Google.ProtocolBuffers.ProtoGen
 
         private void WriteIntroduction(TextGenerator writer)
         {
-            writer.WriteLine("// Generated by {0}.  DO NOT EDIT!", this.GetType().Assembly.FullName);
-            writer.WriteLine("#pragma warning disable 1591");
+            writer.WriteLine("// Generated by {0}.  DO NOT EDIT!", this.GetType().Assembly.FullName);
+            writer.WriteLine("#pragma warning disable 1591, 0612");
             writer.WriteLine("#region Designer generated code");
 
             writer.WriteLine();

src/ProtocolBuffers.Test/CodedInputStreamTest.cs

@@ -35,6 +35,7 @@
 #endregion
 
 using System;
+using System.Collections.Generic;
 using System.IO;
 using Google.ProtocolBuffers.TestProtos;
 using NUnit.Framework;
@@ -532,5 +533,77 @@ namespace Google.ProtocolBuffers
                 return base.Read(buffer, offset, Math.Min(count, blockSize));
             }
         }
+
+        enum TestNegEnum { None = 0, Value = -2 }
+
+        [Test]
+        public void TestNegativeEnum()
+        {
+            byte[] bytes = new byte[10] { 0xFE, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x01 };
+            CodedInputStream input = CodedInputStream.CreateInstance(bytes);
+            object unk;
+            TestNegEnum val = TestNegEnum.None;
+
+            Assert.IsTrue(input.ReadEnum(ref val, out unk));
+            Assert.IsTrue(input.IsAtEnd);
+            Assert.AreEqual(TestNegEnum.Value, val);
+        }
+
+        [Test]
+        public void TestNegativeEnumPackedArray()
+        {
+            int arraySize = 1 + (10 * 5);
+            int msgSize = 1 + 1 + arraySize;
+            byte[] bytes = new byte[msgSize];
+            CodedOutputStream output = CodedOutputStream.CreateInstance(bytes);
+            output.WritePackedInt32Array(8, "", arraySize, new int[] { 0, -1, -2, -3, -4, -5 });
+
+            Assert.AreEqual(0, output.SpaceLeft);
+
+            CodedInputStream input = CodedInputStream.CreateInstance(bytes);
+            uint tag;
+            string name;
+            Assert.IsTrue(input.ReadTag(out tag, out name));
+
+            List<TestNegEnum> values = new List<TestNegEnum>();
+            ICollection<object> unk;
+            input.ReadEnumArray(tag, name, values, out unk);
+
+            Assert.AreEqual(2, values.Count);
+            Assert.AreEqual(TestNegEnum.None, values[0]);
+            Assert.AreEqual(TestNegEnum.Value, values[1]);
+
+            Assert.IsNotNull(unk);
+            Assert.AreEqual(4, unk.Count);
+        }
+
+        [Test]
+        public void TestNegativeEnumArray()
+        {
+            int arraySize = 1 + 1 + (11 * 5);
+            int msgSize = arraySize;
+            byte[] bytes = new byte[msgSize];
+            CodedOutputStream output = CodedOutputStream.CreateInstance(bytes);
+            output.WriteInt32Array(8, "", new int[] { 0, -1, -2, -3, -4, -5 });
+
+            Assert.AreEqual(0, output.SpaceLeft);
+
+            CodedInputStream input = CodedInputStream.CreateInstance(bytes);
+            uint tag;
+            string name;
+            Assert.IsTrue(input.ReadTag(out tag, out name));
+
+            List<TestNegEnum> values = new List<TestNegEnum>();
+            ICollection<object> unk;
+            input.ReadEnumArray(tag, name, values, out unk);
+
+            Assert.AreEqual(2, values.Count);
+            Assert.AreEqual(TestNegEnum.None, values[0]);
+            Assert.AreEqual(TestNegEnum.Value, values[1]);
+
+            Assert.IsNotNull(unk);
+            Assert.AreEqual(4, unk.Count);
+        }
+
     }
 }
\ No newline at end of file

src/ProtocolBuffers.Test/CodedOutputStreamTest.cs

@@ -34,6 +34,8 @@
 
 #endregion
 
+using System;
+using System.Collections.Generic;
 using System.IO;
 using Google.ProtocolBuffers.TestProtos;
 using NUnit.Framework;
@@ -288,5 +290,82 @@ namespace Google.ProtocolBuffers
             Assert.AreEqual(-75123905439571256L,
                             CodedInputStream.DecodeZigZag64(CodedOutputStream.EncodeZigZag64(-75123905439571256L)));
         }
+
+        [Test]
+        public void TestNegativeEnumNoTag()
+        {
+            Assert.AreEqual(10, CodedOutputStream.ComputeInt32SizeNoTag(-2));
+            Assert.AreEqual(10, CodedOutputStream.ComputeEnumSizeNoTag(-2));
+
+            byte[] bytes = new byte[10];
+            CodedOutputStream output = CodedOutputStream.CreateInstance(bytes);
+            output.WriteEnumNoTag(-2);
+
+            Assert.AreEqual(0, output.SpaceLeft);
+            Assert.AreEqual("FE-FF-FF-FF-FF-FF-FF-FF-FF-01", BitConverter.ToString(bytes));
+        }
+
+        [Test]
+        public void TestNegativeEnumWithTag()
+        {
+            Assert.AreEqual(11, CodedOutputStream.ComputeInt32Size(8, -2));
+            Assert.AreEqual(11, CodedOutputStream.ComputeEnumSize(8, -2));
+
+            byte[] bytes = new byte[11];
+            CodedOutputStream output = CodedOutputStream.CreateInstance(bytes);
+            output.WriteEnum(8, "", -2, -2);
+
+            Assert.AreEqual(0, output.SpaceLeft);
+            //fyi, 0x40 == 0x08 << 3 + 0, field num + wire format shift
+            Assert.AreEqual("40-FE-FF-FF-FF-FF-FF-FF-FF-FF-01", BitConverter.ToString(bytes));
+        }
+
+        [Test]
+        public void TestNegativeEnumArrayPacked()
+        {
+            int arraySize = 1 + (10 * 5);
+            int msgSize = 1 + 1 + arraySize;
+            byte[] bytes = new byte[msgSize];
+            CodedOutputStream output = CodedOutputStream.CreateInstance(bytes);
+            output.WritePackedEnumArray(8, "", arraySize, new int[] { 0, -1, -2, -3, -4, -5 });
+
+            Assert.AreEqual(0, output.SpaceLeft);
+
+            CodedInputStream input = CodedInputStream.CreateInstance(bytes);
+            uint tag;
+            string name;
+            Assert.IsTrue(input.ReadTag(out tag, out name));
+
+            List<int> values = new List<int>();
+            input.ReadInt32Array(tag, name, values);
+
+            Assert.AreEqual(6, values.Count);
+            for (int i = 0; i > -6; i--)
+                Assert.AreEqual(i, values[Math.Abs(i)]);
+        }
+
+        [Test]
+        public void TestNegativeEnumArray()
+        {
+            int arraySize = 1 + 1 + (11 * 5);
+            int msgSize = arraySize;
+            byte[] bytes = new byte[msgSize];
+            CodedOutputStream output = CodedOutputStream.CreateInstance(bytes);
+            output.WriteEnumArray(8, "", new int[] { 0, -1, -2, -3, -4, -5 });
+
+            Assert.AreEqual(0, output.SpaceLeft);
+
+            CodedInputStream input = CodedInputStream.CreateInstance(bytes);
+            uint tag;
+            string name;
+            Assert.IsTrue(input.ReadTag(out tag, out name));
+
+            List<int> values = new List<int>();
+            input.ReadInt32Array(tag, name, values);
+
+            Assert.AreEqual(6, values.Count);
+            for (int i = 0; i > -6; i--)
+                Assert.AreEqual(i, values[Math.Abs(i)]);
+        }
     }
 }
\ No newline at end of file

src/ProtocolBuffers.Test/Collections/PopsicleListTest.cs

@@ -35,6 +35,7 @@
 #endregion
 
 using System;
+using System.Collections.Generic;
 using NUnit.Framework;
 
 internal delegate void Action();
@@ -94,6 +95,64 @@ namespace Google.ProtocolBuffers.Collections
             Assert.IsFalse(list.IsReadOnly);
         }
 
+        [Test]
+        public void DoesNotAddNullEnumerable()
+        {
+            PopsicleList<string> list = new PopsicleList<string>();
+            try
+            {
+                list.Add((IEnumerable<string>)null);
+            }
+            catch (ArgumentNullException)
+            { return; }
+
+            Assert.Fail("List should not allow nulls.");
+        }
+
+        [Test]
+        public void DoesNotAddRangeWithNull()
+        {
+            PopsicleList<string> list = new PopsicleList<string>();
+            try
+            {
+                list.Add(new[] { "a", "b", null });
+            }
+            catch (ArgumentNullException)
+            { return; }
+
+            Assert.Fail("List should not allow nulls.");
+        }
+
+        [Test]
+        public void DoesNotAddNull()
+        {
+            PopsicleList<string> list = new PopsicleList<string>();
+            try
+            {
+                list.Add((string)null);
+            }
+            catch (ArgumentNullException)
+            { return; }
+
+            Assert.Fail("List should not allow nulls.");
+        }
+
+        [Test]
+        public void DoesNotSetNull()
+        {
+            PopsicleList<string> list = new PopsicleList<string>();
+            list.Add("a");
+            try
+            {
+                list[0] = null;
+            }
+            catch (ArgumentNullException)
+            { return; }
+
+            Assert.Fail("List should not allow nulls.");
+        }
+
+
         private static void AssertNotSupported(Action action)
         {
             try

src/ProtocolBuffers.Test/DeprecatedMemberTest.cs

+using System;
+using System.Collections.Generic;
+using System.Reflection;
+using System.Text;
+using NUnit.Framework;
+using UnitTest.Issues.TestProtos;
+
+namespace Google.ProtocolBuffers
+{
+    [TestFixture]
+    public class DeprecatedMemberTest
+    {
+        private static void AssertIsDeprecated(ICustomAttributeProvider member)
+        {
+            Assert.IsNotNull(member);
+            Assert.IsTrue(member.IsDefined(typeof(ObsoleteAttribute), false), "Member not obsolete: " + member);
+        }
+
+        [Test]
+        public void TestDepreatedPrimitiveValue()
+        {
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage).GetProperty("HasPrimitiveValue"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage).GetProperty("PrimitiveValue"));
+
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetProperty("HasPrimitiveValue"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetProperty("PrimitiveValue"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetMethod("ClearPrimitiveValue"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetMethod("SetPrimitiveValue"));
+        }
+        [Test]
+        public void TestDepreatedPrimitiveArray()
+        {
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage).GetProperty("PrimitiveArrayList"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage).GetProperty("PrimitiveArrayCount"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage).GetMethod("GetPrimitiveArray"));
+
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetProperty("PrimitiveArrayList"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetProperty("PrimitiveArrayCount"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetMethod("GetPrimitiveArray"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetMethod("SetPrimitiveArray"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetMethod("AddPrimitiveArray"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetMethod("AddRangePrimitiveArray"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetMethod("ClearPrimitiveArray"));
+        }
+        [Test]
+        public void TestDepreatedMessageValue()
+        {
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage).GetProperty("HasMessageValue"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage).GetProperty("MessageValue"));
+
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetProperty("HasMessageValue"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetProperty("MessageValue"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetMethod("MergeMessageValue"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetMethod("ClearMessageValue"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetMethod("SetMessageValue", new[] { typeof(DeprecatedChild) }));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetMethod("SetMessageValue", new[] { typeof(DeprecatedChild.Builder) }));
+        }
+        [Test]
+        public void TestDepreatedMessageArray()
+        {
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage).GetProperty("MessageArrayList"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage).GetProperty("MessageArrayCount"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage).GetMethod("GetMessageArray"));
+
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetProperty("MessageArrayList"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetProperty("MessageArrayCount"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetMethod("GetMessageArray"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetMethod("SetMessageArray", new[] { typeof(int), typeof(DeprecatedChild) }));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetMethod("SetMessageArray", new[] { typeof(int), typeof(DeprecatedChild.Builder) }));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetMethod("AddMessageArray", new[] { typeof(DeprecatedChild) }));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetMethod("AddMessageArray", new[] { typeof(DeprecatedChild.Builder) }));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetMethod("AddRangeMessageArray"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetMethod("ClearMessageArray"));
+        }
+        [Test]
+        public void TestDepreatedEnumValue()
+        {
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage).GetProperty("HasEnumValue"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage).GetProperty("EnumValue"));
+
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetProperty("HasEnumValue"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetProperty("EnumValue"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetMethod("ClearEnumValue"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetMethod("SetEnumValue"));
+        }
+        [Test]
+        public void TestDepreatedEnumArray()
+        {
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage).GetProperty("EnumArrayList"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage).GetProperty("EnumArrayCount"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage).GetMethod("GetEnumArray"));
+
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetProperty("EnumArrayList"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetProperty("EnumArrayCount"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetMethod("GetEnumArray"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetMethod("SetEnumArray"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetMethod("AddEnumArray"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetMethod("AddRangeEnumArray"));
+            AssertIsDeprecated(typeof(DeprecatedFieldsMessage.Builder).GetMethod("ClearEnumArray"));
+        }
+    }
+}

src/ProtocolBuffers.Test/GeneratedBuilderTest.cs

+using System;
+using System.Collections.Generic;
+using System.Text;
+using Google.ProtocolBuffers.TestProtos;
+using NUnit.Framework;
+
+namespace Google.ProtocolBuffers
+{
+    [TestFixture]
+    public class GeneratedBuilderTest
+    {
+        class OneTimeEnumerator<T> : IEnumerable<T>
+        {
+            readonly T _item;
+            bool _enumerated;
+            public OneTimeEnumerator(T item)
+            {
+                _item = item;
+            }
+            public IEnumerator<T> GetEnumerator()
+            {
+                Assert.IsFalse(_enumerated, "The collection {0} has already been enumerated", GetType());
+                _enumerated = true;
+                yield return _item;
+            }
+            System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
+            { return GetEnumerator(); }
+        }
+
+        [Test]
+        public void DoesNotEnumerateTwiceForMessageList()
+        {
+            TestAllTypes.Builder b = new TestAllTypes.Builder();
+            b.AddRangeRepeatedForeignMessage(
+                new OneTimeEnumerator<ForeignMessage>(
+                    ForeignMessage.DefaultInstance));
+        }
+        [Test]
+        public void DoesNotEnumerateTwiceForPrimitiveList()
+        {
+            TestAllTypes.Builder b = new TestAllTypes.Builder();
+            b.AddRangeRepeatedInt32(new OneTimeEnumerator<int>(1));
+        }
+        [Test]
+        public void DoesNotEnumerateTwiceForStringList()
+        {
+            TestAllTypes.Builder b = new TestAllTypes.Builder();
+            b.AddRangeRepeatedString(new OneTimeEnumerator<string>("test"));
+        }
+        [Test]
+        public void DoesNotEnumerateTwiceForEnumList()
+        {
+            TestAllTypes.Builder b = new TestAllTypes.Builder();
+            b.AddRangeRepeatedForeignEnum(new OneTimeEnumerator<ForeignEnum>(ForeignEnum.FOREIGN_BAR));
+        }
+
+        private static void AssertThrows<T>(System.Threading.ThreadStart method) where T : Exception
+        {
+            try
+            {
+                method();
+            }
+            catch (Exception error)
+            {
+                if (error is T)
+                    return;
+                throw;
+            }
+            Assert.Fail("Expected exception of type " + typeof(T));
+        }
+
+        [Test]
+        public void DoesNotAddNullToMessageListByAddRange()
+        {
+            TestAllTypes.Builder b = new TestAllTypes.Builder();
+            AssertThrows<ArgumentNullException>(
+                () => b.AddRangeRepeatedForeignMessage(new ForeignMessage[] { null })
+                    );
+        }
+        [Test]
+        public void DoesNotAddNullToMessageListByAdd()
+        {
+            TestAllTypes.Builder b = new TestAllTypes.Builder();
+            AssertThrows<ArgumentNullException>(
+                () => b.AddRepeatedForeignMessage((ForeignMessage)null)
+                    );
+        }
+        [Test]
+        public void DoesNotAddNullToMessageListBySet()
+        {
+            TestAllTypes.Builder b = new TestAllTypes.Builder();
+            b.AddRepeatedForeignMessage(ForeignMessage.DefaultInstance);
+            AssertThrows<ArgumentNullException>(
+                () => b.SetRepeatedForeignMessage(0, (ForeignMessage)null)
+                    );
+        }
+        [Test]
+        public void DoesNotAddNullToStringListByAddRange()
+        {
+            TestAllTypes.Builder b = new TestAllTypes.Builder();
+            AssertThrows<ArgumentNullException>(
+                () => b.AddRangeRepeatedString(new String[] { null })
+                    );
+        }
+        [Test]
+        public void DoesNotAddNullToStringListByAdd()
+        {
+            TestAllTypes.Builder b = new TestAllTypes.Builder();
+            AssertThrows<ArgumentNullException>(
+                () => b.AddRepeatedString(null)
+                    );
+        }
+        [Test]
+        public void DoesNotAddNullToStringListBySet()
+        {
+            TestAllTypes.Builder b = new TestAllTypes.Builder();
+            b.AddRepeatedString("one");
+            AssertThrows<ArgumentNullException>(
+                () => b.SetRepeatedString(0, null)
+                    );
+        }
+    }
+}

src/ProtocolBuffers.Test/GeneratedMessageTest.cs

@@ -111,22 +111,6 @@ namespace Google.ProtocolBuffers
             }
         }
 
-        [Test]
-        public void DoubleBuildError()
-        {
-            TestAllTypes.Builder builder = new TestAllTypes.Builder();
-            builder.Build();
-            try
-            {
-                builder.Build();
-                Assert.Fail("Should have thrown exception.");
-            }
-            catch (InvalidOperationException)
-            {
-                // Success.
-            }
-        }
-
         [Test]
         public void DefaultInstance()
         {

src/ProtocolBuffers.Test/ProtocolBuffers.Test.csproj

@@ -45,9 +45,7 @@
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
     <CodeAnalysisRuleSet>AllRules.ruleset</CodeAnalysisRuleSet>
-    <DocumentationFile>bin\Debug\Google.ProtocolBuffers.Test.XML</DocumentationFile>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
-    <NoWarn>1591</NoWarn>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
     <DebugType>pdbonly</DebugType>
@@ -57,9 +55,7 @@
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
     <CodeAnalysisRuleSet>AllRules.ruleset</CodeAnalysisRuleSet>
-    <DocumentationFile>bin\Release\Google.ProtocolBuffers.Test.XML</DocumentationFile>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
-    <NoWarn>1591</NoWarn>
   </PropertyGroup>
   <ItemGroup>
     <Reference Include="nunit.framework, Version=2.2.8.0, Culture=neutral, PublicKeyToken=96d09a1eb7f44a77">
@@ -94,10 +90,12 @@
     <Compile Include="Compatibility\XmlCompatibilityTests.cs" />
     <Compile Include="TestReaderForUrlEncoded.cs" />
     <Compile Include="CSharpOptionsTest.cs" />
+    <Compile Include="DeprecatedMemberTest.cs" />
     <Compile Include="DescriptorsTest.cs" />
     <Compile Include="Descriptors\MessageDescriptorTest.cs" />
     <Compile Include="DynamicMessageTest.cs" />
     <Compile Include="ExtendableMessageTest.cs" />
+    <Compile Include="GeneratedBuilderTest.cs" />
     <Compile Include="GeneratedMessageTest.cs" />
     <Compile Include="MessageStreamIteratorTest.cs" />
     <Compile Include="MessageStreamWriterTest.cs" />
@@ -106,7 +104,10 @@
     <Compile Include="NameHelpersTest.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="ReflectionTester.cs" />
+    <Compile Include="ReusableBuilderTest.cs" />
+    <Compile Include="SerializableTest.cs" />
     <Compile Include="ServiceTest.cs" />
+    <Compile Include="TestCornerCases.cs" />
     <Compile Include="TestMimeMessageFormats.cs" />
     <Compile Include="TestProtos\UnitTestCSharpOptionsProtoFile.cs" />
     <Compile Include="TestProtos\UnitTestCustomOptionsProtoFile.cs" />

src/ProtocolBuffers.Test/ReusableBuilderTest.cs

+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Text;
+using Google.ProtocolBuffers.Collections;
+using NUnit.Framework;
+using Google.ProtocolBuffers.TestProtos;
+using Google.ProtocolBuffers.Serialization;
+using UnitTest.Issues.TestProtos;
+
+namespace Google.ProtocolBuffers
+{
+    [TestFixture]
+    public class ReusableBuilderTest
+    {
+        [Test, Description("Issue 28: Circular message dependencies result in null defaults for DefaultInstance")]
+        public void EnsureStaticCicularReference()
+        {
+            MyMessageAReferenceB ab = MyMessageAReferenceB.DefaultInstance;
+            Assert.IsNotNull(ab);
+            Assert.IsNotNull(ab.Value);
+            MyMessageBReferenceA ba = MyMessageBReferenceA.DefaultInstance;
+            Assert.IsNotNull(ba);
+            Assert.IsNotNull(ba.Value);
+        }
+
+        [Test]
+        public void TestModifyDefaultInstance()
+        {
+            //verify that the default instance has correctly been marked as read-only
+            Assert.AreEqual(typeof(PopsicleList<bool>), TestAllTypes.DefaultInstance.RepeatedBoolList.GetType());
+            PopsicleList<bool> list = (PopsicleList<bool>)TestAllTypes.DefaultInstance.RepeatedBoolList;
+            Assert.IsTrue(list.IsReadOnly);
+        }
+
+        [Test]
+        public void TestUnmodifiedDefaultInstance()
+        {
+            //Simply calling ToBuilder().Build() no longer creates a copy of the message
+            TestAllTypes.Builder builder = TestAllTypes.DefaultInstance.ToBuilder();
+            Assert.IsTrue(ReferenceEquals(TestAllTypes.DefaultInstance, builder.Build()));
+        }
+
+        [Test]
+        public void BuildMultipleWithoutChange()
+        {
+            //Calling Build() or BuildPartial() does not require a copy of the message
+            TestAllTypes.Builder builder = TestAllTypes.DefaultInstance.ToBuilder();
+            builder.SetDefaultBool(true);
+
+            TestAllTypes first = builder.BuildPartial();
+            //Still the same instance?
+            Assert.IsTrue(ReferenceEquals(first, builder.Build()));
+            //Still the same instance?
+            Assert.IsTrue(ReferenceEquals(first, builder.BuildPartial().ToBuilder().Build()));
+        }
+
+        [Test]
+        public void MergeFromDefaultInstance()
+        {
+            TestAllTypes.Builder builder = TestAllTypes.DefaultInstance.ToBuilder();
+            Assert.IsTrue(ReferenceEquals(TestAllTypes.DefaultInstance, builder.Build()));
+            builder.MergeFrom(TestAllTypes.DefaultInstance);
+            Assert.IsTrue(ReferenceEquals(TestAllTypes.DefaultInstance, builder.Build()));
+        }
+
+        [Test]
+        public void BuildNewBuilderIsDefaultInstance()
+        {
+            Assert.IsTrue(ReferenceEquals(TestAllTypes.DefaultInstance, new TestAllTypes.Builder().Build()));
+            Assert.IsTrue(ReferenceEquals(TestAllTypes.DefaultInstance, TestAllTypes.CreateBuilder().Build()));
+            //last test, if you clear a builder it reverts to default instance
+            Assert.IsTrue(ReferenceEquals(TestAllTypes.DefaultInstance,
+                TestAllTypes.CreateBuilder().SetOptionalBool(true).Build().ToBuilder().Clear().Build()));
+        }
+
+        [Test]
+        public void BuildModifyAndRebuild()
+        {
+            TestAllTypes.Builder b1 = new TestAllTypes.Builder();
+            b1.SetDefaultInt32(1);
+            b1.AddRepeatedInt32(2);
+            b1.SetOptionalForeignMessage(ForeignMessage.DefaultInstance);
+
+            TestAllTypes m1 = b1.Build();
+
+            b1.SetDefaultInt32(5);
+            b1.AddRepeatedInt32(6);
+            b1.SetOptionalForeignMessage(b1.OptionalForeignMessage.ToBuilder().SetC(7));
+
+            TestAllTypes m2 = b1.Build();
+            
+            Assert.AreEqual("{\"optional_foreign_message\":{},\"repeated_int32\":[2],\"default_int32\":1}", m1.ToJson());
+            Assert.AreEqual("{\"optional_foreign_message\":{\"c\":7},\"repeated_int32\":[2,6],\"default_int32\":5}", m2.ToJson());
+        }
+
+        [Test]
+        public void CloneOnChangePrimitive()
+        {
+            TestAllTypes.Builder builder = TestAllTypes.DefaultInstance.ToBuilder();
+            Assert.IsTrue(ReferenceEquals(TestAllTypes.DefaultInstance, builder.Build()));
+            builder.SetDefaultBool(true);
+            Assert.IsFalse(ReferenceEquals(TestAllTypes.DefaultInstance, builder.Build()));
+        }
+
+        [Test]
+        public void CloneOnAddRepeatedBool()
+        {
+            TestAllTypes.Builder builder = TestAllTypes.DefaultInstance.ToBuilder();
+            Assert.IsTrue(ReferenceEquals(TestAllTypes.DefaultInstance, builder.Build()));
+            builder.AddRepeatedBool(true);
+            Assert.IsFalse(ReferenceEquals(TestAllTypes.DefaultInstance, builder.Build()));
+        }
+
+        [Test]
+        public void CloneOnGetRepeatedBoolList()
+        {
+            TestAllTypes.Builder builder = TestAllTypes.DefaultInstance.ToBuilder();
+            Assert.IsTrue(ReferenceEquals(TestAllTypes.DefaultInstance, builder.Build()));
+            GC.KeepAlive(builder.RepeatedBoolList);
+            Assert.IsFalse(ReferenceEquals(TestAllTypes.DefaultInstance, builder.Build()));
+        }
+
+        [Test]
+        public void CloneOnChangeMessage()
+        {
+            TestAllTypes.Builder builder = TestAllTypes.DefaultInstance.ToBuilder();
+            Assert.IsTrue(ReferenceEquals(TestAllTypes.DefaultInstance, builder.Build()));
+            builder.SetOptionalForeignMessage(new ForeignMessage.Builder());
+            Assert.IsFalse(ReferenceEquals(TestAllTypes.DefaultInstance, builder.Build()));
+        }
+
+        [Test]
+        public void CloneOnClearMessage()
+        {
+            TestAllTypes.Builder builder = TestAllTypes.DefaultInstance.ToBuilder();
+            Assert.IsTrue(ReferenceEquals(TestAllTypes.DefaultInstance, builder.Build()));
+            builder.ClearOptionalForeignMessage();
+            Assert.IsFalse(ReferenceEquals(TestAllTypes.DefaultInstance, builder.Build()));
+        }
+
+        [Test]
+        public void CloneOnGetRepeatedForeignMessageList()
+        {
+            TestAllTypes.Builder builder = TestAllTypes.DefaultInstance.ToBuilder();
+            Assert.IsTrue(ReferenceEquals(TestAllTypes.DefaultInstance, builder.Build()));
+            GC.KeepAlive(builder.RepeatedForeignMessageList);
+            Assert.IsFalse(ReferenceEquals(TestAllTypes.DefaultInstance, builder.Build()));
+        }
+
+        [Test]
+        public void CloneOnChangeEnumValue()
+        {
+            TestAllTypes.Builder builder = TestAllTypes.DefaultInstance.ToBuilder();
+            Assert.IsTrue(ReferenceEquals(TestAllTypes.DefaultInstance, builder.Build()));
+            builder.SetOptionalForeignEnum(ForeignEnum.FOREIGN_BAR);
+            Assert.IsFalse(ReferenceEquals(TestAllTypes.DefaultInstance, builder.Build()));
+        }
+
+        [Test]
+        public void CloneOnGetRepeatedForeignEnumList()
+        {
+            TestAllTypes.Builder builder = TestAllTypes.DefaultInstance.ToBuilder();
+            Assert.IsTrue(ReferenceEquals(TestAllTypes.DefaultInstance, builder.Build()));
+            GC.KeepAlive(builder.RepeatedForeignEnumList);
+            Assert.IsFalse(ReferenceEquals(TestAllTypes.DefaultInstance, builder.Build()));
+        }
+
+    }
+}

src/ProtocolBuffers.Test/SerializableTest.cs

+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Runtime.Serialization;
+using System.Runtime.Serialization.Formatters.Binary;
+using System.Text;
+using Google.ProtocolBuffers.TestProtos;
+using NUnit.Framework;
+
+namespace Google.ProtocolBuffers
+{
+    [TestFixture]
+    public class SerializableTest
+    {
+        /// <summary>
+        /// Just keep it from even compiling if we these objects don't implement the expected interface.
+        /// </summary>
+        public static readonly ISerializable CompileTimeCheckSerializableMessage = TestXmlMessage.DefaultInstance;
+        public static readonly ISerializable CompileTimeCheckSerializableBuilder = new TestXmlMessage.Builder();
+
+        [Test]
+        public void TestPlainMessage()
+        {
+            TestXmlMessage message = TestXmlMessage.CreateBuilder()
+                .SetValid(true)
+                .SetText("text")
+                .AddTextlines("a")
+                .AddTextlines("b")
+                .AddTextlines("c")
+                .SetNumber(0x1010101010)
+                .AddNumbers(1)
+                .AddNumbers(2)
+                .AddNumbers(3)
+                .SetChild(TestXmlChild.CreateBuilder()
+                                      .AddOptions(EnumOptions.ONE)
+                                      .SetBinary(ByteString.CopyFrom(new byte[1])))
+                .AddChildren(TestXmlMessage.Types.Children.CreateBuilder()
+                                                          .AddOptions(EnumOptions.TWO)
+                                                          .SetBinary(ByteString.CopyFrom(new byte[2])))
+                .AddChildren(TestXmlMessage.Types.Children.CreateBuilder()
+                                                          .AddOptions(EnumOptions.THREE)
+                                                          .SetBinary(ByteString.CopyFrom(new byte[3])))
+                .Build();
+
+            MemoryStream ms = new MemoryStream();
+            new BinaryFormatter().Serialize(ms, message);
+
+            ms.Position = 0;
+            TestXmlMessage copy = (TestXmlMessage)new BinaryFormatter().Deserialize(ms);
+
+            Assert.AreEqual(message, copy);
+        }
+
+        [Test]
+        public void TestMessageWithExtensions()
+        {
+            TestXmlMessage message = TestXmlMessage.CreateBuilder()
+                .SetValid(true)
+                .SetText("text")
+                .AddTextlines("a")
+                .AddTextlines("b")
+                .AddTextlines("c")
+                .SetNumber(0x1010101010)
+                .AddNumbers(1)
+                .AddNumbers(2)
+                .AddNumbers(3)
+                .SetChild(TestXmlChild.CreateBuilder()
+                                      .AddOptions(EnumOptions.ONE)
+                                      .SetBinary(ByteString.CopyFrom(new byte[1])))
+                .AddChildren(TestXmlMessage.Types.Children.CreateBuilder()
+                                                          .AddOptions(EnumOptions.TWO)
+                                                          .SetBinary(ByteString.CopyFrom(new byte[2])))
+                .AddChildren(TestXmlMessage.Types.Children.CreateBuilder()
+                                                          .AddOptions(EnumOptions.THREE)
+                                                          .SetBinary(ByteString.CopyFrom(new byte[3])))
+                .SetExtension(UnitTestXmlSerializerTestProtoFile.ExtensionText, " extension text value ! ")
+                .SetExtension(UnitTestXmlSerializerTestProtoFile.ExtensionMessage, new TestXmlExtension.Builder().SetNumber(42).Build())
+                .AddExtension(UnitTestXmlSerializerTestProtoFile.ExtensionNumber, 100)
+                .AddExtension(UnitTestXmlSerializerTestProtoFile.ExtensionNumber, 101)
+                .AddExtension(UnitTestXmlSerializerTestProtoFile.ExtensionNumber, 102)
+                .SetExtension(UnitTestXmlSerializerTestProtoFile.ExtensionEnum, EnumOptions.ONE)
+                .Build();
+
+            ExtensionRegistry registry = ExtensionRegistry.CreateInstance();
+            UnitTestXmlSerializerTestProtoFile.RegisterAllExtensions(registry);
+
+            MemoryStream ms = new MemoryStream();
+            new BinaryFormatter().Serialize(ms, message);
+
+            ms.Position = 0;
+            //you need to provide the extension registry as context to the serializer
+            BinaryFormatter bff = new BinaryFormatter(null, new StreamingContext(StreamingContextStates.All, registry));
+            TestXmlMessage copy = (TestXmlMessage)bff.Deserialize(ms);
+
+            // And all extensions will be defined.
+            Assert.AreEqual(message, copy);
+        }
+
+        [Test]
+        public void TestPlainBuilder()
+        {
+            TestXmlMessage.Builder builder = TestXmlMessage.CreateBuilder()
+                .SetValid(true)
+                .SetText("text")
+                .AddTextlines("a")
+                .AddTextlines("b")
+                .AddTextlines("c")
+                .SetNumber(0x1010101010)
+                .AddNumbers(1)
+                .AddNumbers(2)
+                .AddNumbers(3)
+                .SetChild(TestXmlChild.CreateBuilder()
+                                      .AddOptions(EnumOptions.ONE)
+                                      .SetBinary(ByteString.CopyFrom(new byte[1])))
+                .AddChildren(TestXmlMessage.Types.Children.CreateBuilder()
+                                                          .AddOptions(EnumOptions.TWO)
+                                                          .SetBinary(ByteString.CopyFrom(new byte[2])))
+                .AddChildren(TestXmlMessage.Types.Children.CreateBuilder()
+                                                          .AddOptions(EnumOptions.THREE)
+                                                          .SetBinary(ByteString.CopyFrom(new byte[3])))
+                ;
+
+            MemoryStream ms = new MemoryStream();
+            new BinaryFormatter().Serialize(ms, builder);
+
+            ms.Position = 0;
+            TestXmlMessage.Builder copy = (TestXmlMessage.Builder)new BinaryFormatter().Deserialize(ms);
+
+            Assert.AreEqual(builder.Build(), copy.Build());
+        }
+
+        [Test]
+        public void TestBuilderWithExtensions()
+        {
+            TestXmlMessage.Builder builder = TestXmlMessage.CreateBuilder()
+                .SetValid(true)
+                .SetText("text")
+                .AddTextlines("a")
+                .AddTextlines("b")
+                .AddTextlines("c")
+                .SetNumber(0x1010101010)
+                .AddNumbers(1)
+                .AddNumbers(2)
+                .AddNumbers(3)
+                .SetChild(TestXmlChild.CreateBuilder()
+                                      .AddOptions(EnumOptions.ONE)
+                                      .SetBinary(ByteString.CopyFrom(new byte[1])))
+                .AddChildren(TestXmlMessage.Types.Children.CreateBuilder()
+                                                          .AddOptions(EnumOptions.TWO)
+                                                          .SetBinary(ByteString.CopyFrom(new byte[2])))
+                .AddChildren(TestXmlMessage.Types.Children.CreateBuilder()
+                                                          .AddOptions(EnumOptions.THREE)
+                                                          .SetBinary(ByteString.CopyFrom(new byte[3])))
+                .SetExtension(UnitTestXmlSerializerTestProtoFile.ExtensionText, " extension text value ! ")
+                .SetExtension(UnitTestXmlSerializerTestProtoFile.ExtensionMessage, new TestXmlExtension.Builder().SetNumber(42).Build())
+                .AddExtension(UnitTestXmlSerializerTestProtoFile.ExtensionNumber, 100)
+                .AddExtension(UnitTestXmlSerializerTestProtoFile.ExtensionNumber, 101)
+                .AddExtension(UnitTestXmlSerializerTestProtoFile.ExtensionNumber, 102)
+                .SetExtension(UnitTestXmlSerializerTestProtoFile.ExtensionEnum, EnumOptions.ONE)
+                ;
+
+            ExtensionRegistry registry = ExtensionRegistry.CreateInstance();
+            UnitTestXmlSerializerTestProtoFile.RegisterAllExtensions(registry);
+
+            MemoryStream ms = new MemoryStream();
+            new BinaryFormatter().Serialize(ms, builder);
+
+            ms.Position = 0;
+            //you need to provide the extension registry as context to the serializer
+            BinaryFormatter bff = new BinaryFormatter(null, new StreamingContext(StreamingContextStates.All, registry));
+            TestXmlMessage.Builder copy = (TestXmlMessage.Builder)bff.Deserialize(ms);
+
+            // And all extensions will be defined.
+            Assert.AreEqual(builder.Build(), copy.Build());
+        }
+    }
+}

src/ProtocolBuffers.Test/TestCornerCases.cs

+using System;
+using System.Collections.Generic;
+using System.Text;
+using NUnit.Framework;
+using UnitTest.Issues.TestProtos;
+
+namespace Google.ProtocolBuffers
+{
+    [TestFixture]
+    public class TestCornerCases
+    {
+        [Test]
+        public void TestRoundTripNegativeEnums()
+        {
+            NegativeEnumMessage msg = NegativeEnumMessage.CreateBuilder()
+                .SetValue(NegativeEnum.MinusOne) //11
+                .AddValues(NegativeEnum.Zero) //2
+                .AddValues(NegativeEnum.MinusOne) //11
+                .AddValues(NegativeEnum.FiveBelow) //11
+                //2
+                .AddPackedValues(NegativeEnum.Zero) //1
+                .AddPackedValues(NegativeEnum.MinusOne) //10
+                .AddPackedValues(NegativeEnum.FiveBelow) //10
+                .Build();
+
+            Assert.AreEqual(58, msg.SerializedSize);
+
+            byte[] bytes = new byte[58];
+            CodedOutputStream output = CodedOutputStream.CreateInstance(bytes);
+
+            msg.WriteTo(output);
+            Assert.AreEqual(0, output.SpaceLeft);
+
+            NegativeEnumMessage copy = NegativeEnumMessage.ParseFrom(bytes);
+            Assert.AreEqual(msg, copy);
+        }
+    }
+}

src/ProtocolBuffers.Test/TestProtos/UnitTestCSharpOptionsProtoFile.cs

 // Generated by ProtoGen, Version=2.3.0.277, Culture=neutral, PublicKeyToken=17b3b1f090c3ea48.  DO NOT EDIT!
-#pragma warning disable 1591
+#pragma warning disable 1591, 0612
 #region Designer generated code
 
 using pb = global::Google.ProtocolBuffers;
@@ -60,7 +60,8 @@ namespace Google.ProtocolBuffers.TestProtos {
   [global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()]
   [global::System.CodeDom.Compiler.GeneratedCodeAttribute("ProtoGen", "2.3.0.277")]
   public sealed partial class OptionsMessage : pb::GeneratedMessage<OptionsMessage, OptionsMessage.Builder> {
-    private static readonly OptionsMessage defaultInstance = new Builder().BuildPartial();
+    private OptionsMessage() { }
+    private static readonly OptionsMessage defaultInstance = new OptionsMessage().MakeReadOnly();
     private static readonly string[] _optionsMessageFieldNames = new string[] { "customized", "normal", "options_message" };
     private static readonly uint[] _optionsMessageFieldTags = new uint[] { 26, 10, 18 };
     public static OptionsMessage DefaultInstance {
@@ -68,7 +69,7 @@ namespace Google.ProtocolBuffers.TestProtos {
     }
     
     public override OptionsMessage DefaultInstanceForType {
-      get { return defaultInstance; }
+      get { return DefaultInstance; }
     }
     
     protected override OptionsMessage ThisMessage {
@@ -186,11 +187,15 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static OptionsMessage ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
+    private OptionsMessage MakeReadOnly() {
+      return this;
+    }
+    
     public static Builder CreateBuilder() { return new Builder(); }
     public override Builder ToBuilder() { return CreateBuilder(this); }
     public override Builder CreateBuilderForType() { return new Builder(); }
     public static Builder CreateBuilder(OptionsMessage prototype) {
-      return (Builder) new Builder().MergeFrom(prototype);
+      return new Builder(prototype);
     }
     
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
@@ -200,21 +205,48 @@ namespace Google.ProtocolBuffers.TestProtos {
       protected override Builder ThisBuilder {
         get { return this; }
       }
-      public Builder() {}
+      public Builder() {
+        result = DefaultInstance;
+        resultIsReadOnly = true;
+      }
+      internal Builder(OptionsMessage cloneFrom) {
+        result = cloneFrom;
+        resultIsReadOnly = true;
+      }
+      
+      private bool resultIsReadOnly;
+      private OptionsMessage result;
+      
+      private OptionsMessage PrepareBuilder() {
+        if (resultIsReadOnly) {
+          OptionsMessage original = result;
+          result = new OptionsMessage();
+          resultIsReadOnly = false;
+          MergeFrom(original);
+        }
+        return result;
+      }
       
-      OptionsMessage result = new OptionsMessage();
+      public override bool IsInitialized {
+        get { return result.IsInitialized; }
+      }
       
       protected override OptionsMessage MessageBeingBuilt {
-        get { return result; }
+        get { return PrepareBuilder(); }
       }
       
       public override Builder Clear() {
-        result = new OptionsMessage();
+        result = DefaultInstance;
+        resultIsReadOnly = true;
         return this;
       }
       
       public override Builder Clone() {
-        return new Builder().MergeFrom(result);
+        if (resultIsReadOnly) {
+          return new Builder(result);
+        } else {
+          return new Builder().MergeFrom(result);
+        }
       }
       
       public override pbd::MessageDescriptor DescriptorForType {
@@ -226,12 +258,11 @@ namespace Google.ProtocolBuffers.TestProtos {
       }
       
       public override OptionsMessage BuildPartial() {
-        if (result == null) {
-          throw new global::System.InvalidOperationException("build() has already been called on this Builder");
+        if (resultIsReadOnly) {
+          return result;
         }
-        OptionsMessage returnMe = result;
-        result = null;
-        return returnMe;
+        resultIsReadOnly = true;
+        return result.MakeReadOnly();
       }
       
       public override Builder MergeFrom(pb::IMessage other) {
@@ -245,6 +276,7 @@ namespace Google.ProtocolBuffers.TestProtos {
       
       public override Builder MergeFrom(OptionsMessage other) {
         if (other == global::Google.ProtocolBuffers.TestProtos.OptionsMessage.DefaultInstance) return this;
+        PrepareBuilder();
         if (other.HasNormal) {
           Normal = other.Normal;
         }
@@ -263,6 +295,7 @@ namespace Google.ProtocolBuffers.TestProtos {
       }
       
       public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        PrepareBuilder();
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -327,11 +360,13 @@ namespace Google.ProtocolBuffers.TestProtos {
       }
       public Builder SetNormal(string value) {
         pb::ThrowHelper.ThrowIfNull(value, "value");
+        PrepareBuilder();
         result.hasNormal = true;
         result.normal_ = value;
         return this;
       }
       public Builder ClearNormal() {
+        PrepareBuilder();
         result.hasNormal = false;
         result.normal_ = "";
         return this;
@@ -346,11 +381,13 @@ namespace Google.ProtocolBuffers.TestProtos {
       }
       public Builder SetOptionsMessage_(string value) {
         pb::ThrowHelper.ThrowIfNull(value, "value");
+        PrepareBuilder();
         result.hasOptionsMessage_ = true;
         result.optionsMessage_ = value;
         return this;
       }
       public Builder ClearOptionsMessage_() {
+        PrepareBuilder();
         result.hasOptionsMessage_ = false;
         result.optionsMessage_ = "";
         return this;
@@ -365,11 +402,13 @@ namespace Google.ProtocolBuffers.TestProtos {
       }
       public Builder SetCustomName(string value) {
         pb::ThrowHelper.ThrowIfNull(value, "value");
+        PrepareBuilder();
         result.hasCustomName = true;
         result.customized_ = value;
         return this;
       }
       public Builder ClearCustomName() {
+        PrepareBuilder();
         result.hasCustomName = false;
         result.customized_ = "";
         return this;

src/ProtocolBuffers.Test/TestProtos/UnitTestEmptyProtoFile.cs

 // Generated by ProtoGen, Version=2.3.0.277, Culture=neutral, PublicKeyToken=17b3b1f090c3ea48.  DO NOT EDIT!
-#pragma warning disable 1591
+#pragma warning disable 1591, 0612
 #region Designer generated code
 
 using pb = global::Google.ProtocolBuffers;

src/ProtocolBuffers.Test/TestProtos/UnitTestGenericServices.cs

 // Generated by ProtoGen, Version=2.3.0.277, Culture=neutral, PublicKeyToken=17b3b1f090c3ea48.  DO NOT EDIT!
-#pragma warning disable 1591
+#pragma warning disable 1591, 0612
 #region Designer generated code
 
 using pb = global::Google.ProtocolBuffers;

src/ProtocolBuffers.Test/TestProtos/UnitTestImportLiteProtoFile.cs

 // Generated by ProtoGen, Version=2.3.0.277, Culture=neutral, PublicKeyToken=17b3b1f090c3ea48.  DO NOT EDIT!
-#pragma warning disable 1591
+#pragma warning disable 1591, 0612
 #region Designer generated code
 
 using pb = global::Google.ProtocolBuffers;
@@ -43,7 +43,8 @@ namespace Google.ProtocolBuffers.TestProtos {
   [global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()]
   [global::System.CodeDom.Compiler.GeneratedCodeAttribute("ProtoGen", "2.3.0.277")]
   public sealed partial class ImportMessageLite : pb::GeneratedMessageLite<ImportMessageLite, ImportMessageLite.Builder> {
-    private static readonly ImportMessageLite defaultInstance = new Builder().BuildPartial();
+    private ImportMessageLite() { }
+    private static readonly ImportMessageLite defaultInstance = new ImportMessageLite().MakeReadOnly();
     private static readonly string[] _importMessageLiteFieldNames = new string[] { "d" };
     private static readonly uint[] _importMessageLiteFieldTags = new uint[] { 8 };
     public static ImportMessageLite DefaultInstance {
@@ -51,7 +52,7 @@ namespace Google.ProtocolBuffers.TestProtos {
     }
     
     public override ImportMessageLite DefaultInstanceForType {
-      get { return defaultInstance; }
+      get { return DefaultInstance; }
     }
     
     protected override ImportMessageLite ThisMessage {
@@ -146,11 +147,15 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static ImportMessageLite ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
+    private ImportMessageLite MakeReadOnly() {
+      return this;
+    }
+    
     public static Builder CreateBuilder() { return new Builder(); }
     public override Builder ToBuilder() { return CreateBuilder(this); }
     public override Builder CreateBuilderForType() { return new Builder(); }
     public static Builder CreateBuilder(ImportMessageLite prototype) {
-      return (Builder) new Builder().MergeFrom(prototype);
+      return new Builder(prototype);
     }
     
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
@@ -160,21 +165,48 @@ namespace Google.ProtocolBuffers.TestProtos {
       protected override Builder ThisBuilder {
         get { return this; }
       }
-      public Builder() {}
+      public Builder() {
+        result = DefaultInstance;
+        resultIsReadOnly = true;
+      }
+      internal Builder(ImportMessageLite cloneFrom) {
+        result = cloneFrom;
+        resultIsReadOnly = true;
+      }
+      
+      private bool resultIsReadOnly;
+      private ImportMessageLite result;
+      
+      private ImportMessageLite PrepareBuilder() {
+        if (resultIsReadOnly) {
+          ImportMessageLite original = result;
+          result = new ImportMessageLite();
+          resultIsReadOnly = false;
+          MergeFrom(original);
+        }
+        return result;
+      }
       
-      ImportMessageLite result = new ImportMessageLite();
+      public override bool IsInitialized {
+        get { return result.IsInitialized; }
+      }
       
       protected override ImportMessageLite MessageBeingBuilt {
-        get { return result; }
+        get { return PrepareBuilder(); }
       }
       
       public override Builder Clear() {
-        result = new ImportMessageLite();
+        result = DefaultInstance;
+        resultIsReadOnly = true;
         return this;
       }
       
       public override Builder Clone() {
-        return new Builder().MergeFrom(result);
+        if (resultIsReadOnly) {
+          return new Builder(result);
+        } else {
+          return new Builder().MergeFrom(result);
+        }
       }
       
       public override ImportMessageLite DefaultInstanceForType {
@@ -182,12 +214,11 @@ namespace Google.ProtocolBuffers.TestProtos {
       }
       
       public override ImportMessageLite BuildPartial() {
-        if (result == null) {
-          throw new global::System.InvalidOperationException("build() has already been called on this Builder");
+        if (resultIsReadOnly) {
+          return result;
         }
-        ImportMessageLite returnMe = result;
-        result = null;
-        return returnMe;
+        resultIsReadOnly = true;
+        return result.MakeReadOnly();
       }
       
       public override Builder MergeFrom(pb::IMessageLite other) {
@@ -201,6 +232,7 @@ namespace Google.ProtocolBuffers.TestProtos {
       
       public override Builder MergeFrom(ImportMessageLite other) {
         if (other == global::Google.ProtocolBuffers.TestProtos.ImportMessageLite.DefaultInstance) return this;
+        PrepareBuilder();
         if (other.HasD) {
           D = other.D;
         }
@@ -212,6 +244,7 @@ namespace Google.ProtocolBuffers.TestProtos {
       }
       
       public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        PrepareBuilder();
         uint tag;
         string field_name;
         while (input.ReadTag(out tag, out field_name)) {
@@ -254,11 +287,13 @@ namespace Google.ProtocolBuffers.TestProtos {
         set { SetD(value); }
       }
       public Builder SetD(int value) {
+        PrepareBuilder();
         result.hasD = true;
         result.d_ = value;
         return this;
       }
       public Builder ClearD() {
+        PrepareBuilder();
         result.hasD = false;
         result.d_ = 0;
         return this;

src/ProtocolBuffers.Test/TestProtos/UnitTestImportProtoFile.cs

 // Generated by ProtoGen, Version=2.3.0.277, Culture=neutral, PublicKeyToken=17b3b1f090c3ea48.  DO NOT EDIT!
-#pragma warning disable 1591
+#pragma warning disable 1591, 0612
 #region Designer generated code
 
 using pb = global::Google.ProtocolBuffers;
@@ -71,7 +71,8 @@ namespace Google.ProtocolBuffers.TestProtos {
   [global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()]
   [global::System.CodeDom.Compiler.GeneratedCodeAttribute("ProtoGen", "2.3.0.277")]
   public sealed partial class ImportMessage : pb::GeneratedMessage<ImportMessage, ImportMessage.Builder> {
-    private static readonly ImportMessage defaultInstance = new Builder().BuildPartial();
+    private ImportMessage() { }
+    private static readonly ImportMessage defaultInstance = new ImportMessage().MakeReadOnly();
     private static readonly string[] _importMessageFieldNames = new string[] { "d" };
     private static readonly uint[] _importMessageFieldTags = new uint[] { 8 };
     public static ImportMessage DefaultInstance {
@@ -79,7 +80,7 @@ namespace Google.ProtocolBuffers.TestProtos {
     }
     
     public override ImportMessage DefaultInstanceForType {
-      get { return defaultInstance; }
+      get { return DefaultInstance; }
     }
     
     protected override ImportMessage ThisMessage {
@@ -165,11 +166,15 @@ namespace Google.ProtocolBuffers.TestProtos {
     public static ImportMessage ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
+    private ImportMessage MakeReadOnly() {
+      return this;
+    }
+    
     public static Builder CreateBuilder() { return new Builder(); }
     public override Builder ToBuilder() { return CreateBuilder(this); }
     public override Builder CreateBuilderForType() { return new Builder(); }
     public static Builder CreateBuilder(ImportMessage prototype) {
-      return (Builder) new Builder().MergeFrom(prototype);
+      return new Builder(prototype);
     }
     
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
@@ -179,21 +184,48 @@ namespace Google.ProtocolBuffers.TestProtos {
       protected override Builder ThisBuilder {
         get { return this; }
       }
-      public Builder() {}
+      public Builder() {
+        result = DefaultInstance;
+        resultIsReadOnly = true;
+      }
+      internal Builder(ImportMessage cloneFrom) {
+        result = cloneFrom;
+        resultIsReadOnly = true;
+      }
+      
+      private bool resultIsReadOnly;
+      private ImportMessage result;
+      
+      private ImportMessage PrepareBuilder() {
+        if (resultIsReadOnly) {
+          ImportMessage original = result;
+          result = new ImportMessage();
+          resultIsReadOnly = false;
+          MergeFrom(original);
+        }
+        return result;
+      }
       
-      ImportMessage result = new ImportMessage();
+      public override bool IsInitialized {
+        get { return result.IsInitialized; }
+      }
       
       protected override ImportMessage MessageBeingBuilt {
-        get { return result; }
+        get { return PrepareBuilder(); }
       }
       
       public override Builder Clear() {
-        result = new ImportMessage();
+        result = DefaultInstance;
+        resultIsReadOnly = true;
         return this;
       }
       
       public override Builder Clone() {
-        return new Builder().MergeFrom(result);
+        if (resultIsReadOnly) {
+          return new Builder(result);
+        } else {
+          return new Builder().MergeFrom(result);
+        }
       }
       
       public override pbd::MessageDescriptor DescriptorForType {
@@ -205,12 +237,11 @@ namespace Google.ProtocolBuffers.TestProtos {
       }
       
       public override ImportMessage BuildPartial() {
-        if (result == null) {
-          throw new global::System.InvalidOperationException("build() has already been called on this Builder");
+        if (resultIsReadOnly) {
+          return result;
         }
-        ImportMessage returnMe = result;
-        result = null;
-        return returnMe;
+        resultIsReadOnly = true;
+        return result.MakeReadOnly();
       }
       
       public override Builder MergeFrom(pb::IMessage other) {
@@ -224,6 +255,7 @@ namespace Google.ProtocolBuffers.TestProtos {
       
       public override Builder MergeFrom(ImportMessage other) {
         if (other == global::Google.ProtocolBuffers.TestProtos.ImportMessage.DefaultInstance) return this;
+        PrepareBuilder();
         if (other.HasD) {
           D = other.D;
         }
@@ -236,6 +268,7 @@ namespace Google.ProtocolBuffers.TestProtos {
       }
       
       public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        PrepareBuilder();
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -291,11 +324,13 @@ namespace Google.ProtocolBuffers.TestProtos {
         set { SetD(value); }
       }
       public Builder SetD(int value) {
+        PrepareBuilder();
         result.hasD = true;
         result.d_ = value;
         return this;
       }
       public Builder ClearD() {
+        PrepareBuilder();
         result.hasD = false;
         result.d_ = 0;
         return this;

src/ProtocolBuffers.Test/TestProtos/UnitTestNoGenericServicesProtoFile.cs

 // Generated by ProtoGen, Version=2.3.0.277, Culture=neutral, PublicKeyToken=17b3b1f090c3ea48.  DO NOT EDIT!
-#pragma warning disable 1591
+#pragma warning disable 1591, 0612
 #region Designer generated code
 
 using pb = global::Google.ProtocolBuffers;
@@ -81,7 +81,8 @@ namespace Google.ProtocolBuffers.TestProtos.NoGenericService {
   [global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()]
   [global::System.CodeDom.Compiler.GeneratedCodeAttribute("ProtoGen", "2.3.0.277")]
   public sealed partial class TestMessage : pb::ExtendableMessage<TestMessage, TestMessage.Builder> {
-    private static readonly TestMessage defaultInstance = new Builder().BuildPartial();
+    private TestMessage() { }
+    private static readonly TestMessage defaultInstance = new TestMessage().MakeReadOnly();
     private static readonly string[] _testMessageFieldNames = new string[] { "a" };
     private static readonly uint[] _testMessageFieldTags = new uint[] { 8 };
     public static TestMessage DefaultInstance {
@@ -89,7 +90,7 @@ namespace Google.ProtocolBuffers.TestProtos.NoGenericService {
     }
     
     public override TestMessage DefaultInstanceForType {
-      get { return defaultInstance; }
+      get { return DefaultInstance; }
     }
     
     protected override TestMessage ThisMessage {
@@ -179,11 +180,15 @@ namespace Google.ProtocolBuffers.TestProtos.NoGenericService {
     public static TestMessage ParseFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
       return ((Builder) CreateBuilder().MergeFrom(input, extensionRegistry)).BuildParsed();
     }
+    private TestMessage MakeReadOnly() {
+      return this;
+    }
+    
     public static Builder CreateBuilder() { return new Builder(); }
     public override Builder ToBuilder() { return CreateBuilder(this); }
     public override Builder CreateBuilderForType() { return new Builder(); }
     public static Builder CreateBuilder(TestMessage prototype) {
-      return (Builder) new Builder().MergeFrom(prototype);
+      return new Builder(prototype);
     }
     
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
@@ -193,21 +198,48 @@ namespace Google.ProtocolBuffers.TestProtos.NoGenericService {
       protected override Builder ThisBuilder {
         get { return this; }
       }
-      public Builder() {}
+      public Builder() {
+        result = DefaultInstance;
+        resultIsReadOnly = true;
+      }
+      internal Builder(TestMessage cloneFrom) {
+        result = cloneFrom;
+        resultIsReadOnly = true;
+      }
+      
+      private bool resultIsReadOnly;
+      private TestMessage result;
+      
+      private TestMessage PrepareBuilder() {
+        if (resultIsReadOnly) {
+          TestMessage original = result;
+          result = new TestMessage();
+          resultIsReadOnly = false;
+          MergeFrom(original);
+        }
+        return result;
+      }
       
-      TestMessage result = new TestMessage();
+      public override bool IsInitialized {
+        get { return result.IsInitialized; }
+      }
       
       protected override TestMessage MessageBeingBuilt {
-        get { return result; }
+        get { return PrepareBuilder(); }
       }
       
       public override Builder Clear() {
-        result = new TestMessage();
+        result = DefaultInstance;
+        resultIsReadOnly = true;
         return this;
       }
       
       public override Builder Clone() {
-        return new Builder().MergeFrom(result);
+        if (resultIsReadOnly) {
+          return new Builder(result);
+        } else {
+          return new Builder().MergeFrom(result);
+        }
       }
       
       public override pbd::MessageDescriptor DescriptorForType {
@@ -219,12 +251,11 @@ namespace Google.ProtocolBuffers.TestProtos.NoGenericService {
       }
       
       public override TestMessage BuildPartial() {
-        if (result == null) {
-          throw new global::System.InvalidOperationException("build() has already been called on this Builder");
+        if (resultIsReadOnly) {
+          return result;
         }
-        TestMessage returnMe = result;
-        result = null;
-        return returnMe;
+        resultIsReadOnly = true;
+        return result.MakeReadOnly();
       }
       
       public override Builder MergeFrom(pb::IMessage other) {
@@ -238,6 +269,7 @@ namespace Google.ProtocolBuffers.TestProtos.NoGenericService {
       
       public override Builder MergeFrom(TestMessage other) {
         if (other == global::Google.ProtocolBuffers.TestProtos.NoGenericService.TestMessage.DefaultInstance) return this;
+        PrepareBuilder();
         if (other.HasA) {
           A = other.A;
         }
@@ -251,6 +283,7 @@ namespace Google.ProtocolBuffers.TestProtos.NoGenericService {
       }
       
       public override Builder MergeFrom(pb::ICodedInputStream input, pb::ExtensionRegistry extensionRegistry) {
+        PrepareBuilder();
         pb::UnknownFieldSet.Builder unknownFields = null;
         uint tag;
         string field_name;
@@ -306,11 +339,13 @@ namespace Google.ProtocolBuffers.TestProtos.NoGenericService {
         set { SetA(value); }
       }
       public Builder SetA(int value) {
+        PrepareBuilder();
         result.hasA = true;
         result.a_ = value;
         return this;
       }
       public Builder ClearA() {
+        PrepareBuilder();
         result.hasA = false;
         result.a_ = 0;
         return this;

src/ProtocolBuffers/AbstractBuilder.cs

@@ -44,7 +44,7 @@ namespace Google.ProtocolBuffers
     /// <summary>
     /// Implementation of the non-generic IMessage interface as far as possible.
     /// </summary>
-    public abstract class AbstractBuilder<TMessage, TBuilder> : AbstractBuilderLite<TMessage, TBuilder>,
+    public abstract partial class AbstractBuilder<TMessage, TBuilder> : AbstractBuilderLite<TMessage, TBuilder>,
                                                                 IBuilder<TMessage, TBuilder>
         where TMessage : AbstractMessage<TMessage, TBuilder>
         where TBuilder : AbstractBuilder<TMessage, TBuilder>

src/ProtocolBuffers/AbstractBuilderLite.cs

@@ -42,7 +42,7 @@ namespace Google.ProtocolBuffers
     /// <summary>
     /// Implementation of the non-generic IMessage interface as far as possible.
     /// </summary>
-    public abstract class AbstractBuilderLite<TMessage, TBuilder> : IBuilderLite<TMessage, TBuilder>
+    public abstract partial class AbstractBuilderLite<TMessage, TBuilder> : IBuilderLite<TMessage, TBuilder>
         where TMessage : AbstractMessageLite<TMessage, TBuilder>
         where TBuilder : AbstractBuilderLite<TMessage, TBuilder>
     {

src/ProtocolBuffers/AbstractMessage.cs

@@ -46,7 +46,7 @@ namespace Google.ProtocolBuffers
     /// <summary>
     /// Implementation of the non-generic IMessage interface as far as possible.
     /// </summary>
-    public abstract class AbstractMessage<TMessage, TBuilder> : AbstractMessageLite<TMessage, TBuilder>,
+    public abstract partial class AbstractMessage<TMessage, TBuilder> : AbstractMessageLite<TMessage, TBuilder>,
                                                                 IMessage<TMessage, TBuilder>
         where TMessage : AbstractMessage<TMessage, TBuilder>
         where TBuilder : AbstractBuilder<TMessage, TBuilder>

src/ProtocolBuffers/AbstractMessageLite.cs

@@ -41,7 +41,7 @@ namespace Google.ProtocolBuffers
     /// <summary>
     /// Implementation of the non-generic IMessage interface as far as possible.
     /// </summary>
-    public abstract class AbstractMessageLite<TMessage, TBuilder> : IMessageLite<TMessage, TBuilder>
+    public abstract partial class AbstractMessageLite<TMessage, TBuilder> : IMessageLite<TMessage, TBuilder>
         where TMessage : AbstractMessageLite<TMessage, TBuilder>
         where TBuilder : AbstractBuilderLite<TMessage, TBuilder>
     {

src/ProtocolBuffers/CodedOutputStream.ComputeSize.cs

@@ -202,7 +202,7 @@ namespace Google.ProtocolBuffers
         /// </summary>
         public static int ComputeEnumSize(int fieldNumber, int value)
         {
-            return ComputeTagSize(fieldNumber) + ComputeRawVarint32Size((uint) value);
+            return ComputeTagSize(fieldNumber) + ComputeEnumSizeNoTag(value);
         }
 
         /// <summary>
@@ -391,7 +391,7 @@ namespace Google.ProtocolBuffers
         /// </summary>
         public static int ComputeEnumSizeNoTag(int value)
         {
-            return ComputeRawVarint32Size((uint) value);
+            return ComputeInt32SizeNoTag(value);
         }
 
         /// <summary>

src/ProtocolBuffers/CodedOutputStream.cs

@@ -388,7 +388,7 @@ namespace Google.ProtocolBuffers
         public void WriteEnum(int fieldNumber, string fieldName, int value, object rawValue)
         {
             WriteTag(fieldNumber, WireFormat.WireType.Varint);
-            WriteRawVarint32((uint) value);
+            WriteInt32NoTag(value);
         }
 
         public void WriteSFixed32(int fieldNumber, string fieldName, int value)
@@ -663,7 +663,7 @@ namespace Google.ProtocolBuffers
 
         public void WriteEnumNoTag(int value)
         {
-            WriteRawVarint32((uint) value);
+            WriteInt32NoTag(value);
         }
 
         public void WriteSFixed32NoTag(int value)

src/ProtocolBuffers/Collections/PopsicleList.cs

@@ -42,6 +42,7 @@ namespace Google.ProtocolBuffers.Collections
     /// </summary>
     public sealed class PopsicleList<T> : IPopsicleList<T>, ICastArray
     {
+        private static readonly bool CheckForNull = default(T) == null;
         private static readonly T[] EmptySet = new T[0];
 
         private List<T> items;
@@ -65,6 +66,10 @@ namespace Google.ProtocolBuffers.Collections
         public void Insert(int index, T item)
         {
             ValidateModification();
+            if (CheckForNull)
+            {
+                ThrowHelper.ThrowIfNull(item);
+            }
             items.Insert(index, item);
         }
 
@@ -87,6 +92,10 @@ namespace Google.ProtocolBuffers.Collections
             set
             {
                 ValidateModification();
+                if (CheckForNull)
+                {
+                    ThrowHelper.ThrowIfNull(value);
+                }
                 items[index] = value;
             }
         }
@@ -94,6 +103,10 @@ namespace Google.ProtocolBuffers.Collections
         public void Add(T item)
         {
             ValidateModification();
+            if (CheckForNull)
+            {
+                ThrowHelper.ThrowIfNull(item);
+            }
             items.Add(item);
         }
 
@@ -145,15 +158,30 @@ namespace Google.ProtocolBuffers.Collections
 
         public void Add(IEnumerable<T> collection)
         {
-            if (readOnly)
+            ValidateModification();
+            ThrowHelper.ThrowIfNull(collection);
+
+            if (!CheckForNull || collection is PopsicleList<T>)
             {
-                throw new NotSupportedException("List is read-only");
+                items.AddRange(collection);
             }
-            if (items == null)
+            else
             {
-                items = new List<T>();
+                // Assumption, it's ok to enumerate collections more than once.
+                if (collection is ICollection<T>)
+                {
+                    ThrowHelper.ThrowIfAnyNull(collection);
+                    items.AddRange(collection);
+                }
+                else
+                {
+                    foreach (T item in collection)
+                    {
+                        ThrowHelper.ThrowIfNull(item);
+                        items.Add(item);
+                    }
+                }
             }
-            items.AddRange(collection);
         }
 
         private void ValidateModification()

src/ProtocolBuffers/DynamicMessage.cs

@@ -44,7 +44,7 @@ namespace Google.ProtocolBuffers
     /// <summary>
     /// An implementation of IMessage that can represent arbitrary types, given a MessageaDescriptor.
     /// </summary>
-    public sealed class DynamicMessage : AbstractMessage<DynamicMessage, DynamicMessage.Builder>
+    public sealed partial class DynamicMessage : AbstractMessage<DynamicMessage, DynamicMessage.Builder>
     {
         private readonly MessageDescriptor type;
         private readonly FieldSet fields;
@@ -308,7 +308,7 @@ namespace Google.ProtocolBuffers
         /// <summary>
         /// Builder for dynamic messages. Instances are created with DynamicMessage.CreateBuilder.
         /// </summary>
-        public sealed class Builder : AbstractBuilder<DynamicMessage, Builder>
+        public sealed partial class Builder : AbstractBuilder<DynamicMessage, Builder>
         {
             private readonly MessageDescriptor type;
             private FieldSet fields;

src/ProtocolBuffers/ExtendableBuilder.cs

@@ -40,7 +40,7 @@ using Google.ProtocolBuffers.Descriptors;
 
 namespace Google.ProtocolBuffers
 {
-    public abstract class ExtendableBuilder<TMessage, TBuilder> : GeneratedBuilder<TMessage, TBuilder>
+    public abstract partial class ExtendableBuilder<TMessage, TBuilder> : GeneratedBuilder<TMessage, TBuilder>
         where TMessage : ExtendableMessage<TMessage, TBuilder>
         where TBuilder : GeneratedBuilder<TMessage, TBuilder>, new()
     {