* Update version to 3.7.0

* Update version number for java bom

* Add several fixes for python toolchain

* Fix versin regex

* Make script exit on error

* Fix version regex

* Fix version regex

* Fix version regex

* Fix version regex

* Make test run on the current commit

* Fix test

* Fix test

* Use git to retrieve current commit

* Fix tests

* Fix tests

* Also make linux and mac work on the current commit

* Fix test

* Down-integrate internal changes to github.

* fix python conformance test

* fix csharp conformance test

* add back java map_lite_test.proto's optimize for option

* fix php conformance test

* Rebuild python docker image

* Update docker image

* Change call to build_and_run_docker.sh

* Set up python tests for different versions

* Fix comments

- Avoid using typeid() so that we don't depend on RTTI
- Change internal AP MapData() to MutableMapData() and added
  GetMapData()

* Add kokoro build for python source package

* Use libc++ for xcode 10 (#5303)

The xcode 10 removes the deprecated libstdc++ library. We could set
"MACOSX_DEPLOYMENT_TARGET" to "10.9" to use libc++ instead.

* Add python 3.7 build

* Add build for python 3.7 on linux and windows

* Remove unused source build

* Add comment

* Fix $MACOSX_DEPLOYMENT_TARGET mismatch

* Fix MACOSX_DEPLOYMENT_TARGET mismatch

* Add missing import for sysconfig

* Add missing imports

* fix json_format.ParseDict modifies input

* added unit test

* fix naming

* Fix parsing empty Struct Values from Json

This fixes a bug. When parsing a struct from JSON like
    struct = json_format.Parse('{"k": {}}', Struct())
then the struct's "k" value would end up not initialized, and accessing
the value would raise an error.
    In[1]: struct['k']
    ValueError: Value not set
That seems to be because the Struct field of the Value was not set.
    In[2]: struct
    Out[2]:
    fields {
      key: "k"
      value {
      }
    }

This commit makes sure that the Value's Struct field is initialized even
if the Struct has no values itself.

This commit also extends a test to cover this case.

* Additionally test for empty list

* ParseFromString returns bytes parsed

ParseFromString is documented as returning the number of bytes parsed,
and the C++ implementation does this, so the Python implementation
should too.

See #5165.

* Fix docstring

* Add a test for ParseFromString length behavior

Many classes within collections were moved to collections.abc in Python
3.3 -- their usage as imported directly from collections is now
deprecated as of Python 3.7 and will be removed soon.

The fallback import added in this PR can be removed entirely when
support for versions of Python prior to 3.3 is dropped.

Python protobuf has long been a single-source codebase. 2to3 shouldn't need to run in setup.py.

* _SURROGATE_PATTERN check for ucs4
Skip some test for ucs2 by sys.maxunicode

1. Fix C++ tests.
  * Add missing files to Makefile.am and fix distcheck in tests.sh
  * Remove BUILT_SOURCES from conformance/Makefile.am.
  * Add some missing override keyword.
  * Add a type cast to int64 because our StrCat() in stubs can't handle size_t.
2. Fix Java tests.
  * Add missing test dependency on guava in pom.xml.
  * Include newly referenced test data in test resources.
  * Manually fix map_lite_test.proto which is overwritten because it's mapped
    from map_test.proto in google3.
  * Add back "optimize_for = LITE_RUNTIME" which is still needed to keep the
    opensource test passing as it's still running lite tests.
  * Add a type cast in newBuilder() because without it the code doesn't compile
    with openjdk javac 1.8 (the compiler can't figure if it's the right type
    due to complex generic typing).
3. Fix Python tests.
  * Remove/replace references to <hash_map>.
  * Suppress more warnings in setup.py.
  * Replace incorrect header inclusion for google/protobuf/proto_api.h.
  * Add strings::EndsWith to google/protobuf/stubs/strutil.h because it's
    referenced in the updated python C extension code.
  * Replace proto2 with google::protobuf. The proto2 name is leaked to
    opensource because we removed the subsitition rule for proto2 namespace
    but only fixed C++ source code and forgot to update python C extension code.

* Remove/replace travis references.

Compilation of Python wrappers fails with Python 3.7 because
the Python folks changed their C API such that
PyUnicode_AsUTF8AndSize() now returns a const char* rather
than a char*. Add a patch to work around. Relates #4086.

* Update message_module.cc

Add missing piece from pull request #4698:  actually initialize the new API object.

* Update message_module.cc

Internal convert file was broken. Change the capsule to the correct name

This change helps both humans and linters to understand the unusual method of instantiating this global variable.

Inspect is used five times on line 65-74 without being imported.

The compiler and util subpackages are created by the build_py class in
setup.py. This has caused an issue in the protobuf package in
conda-forge (https://github.com/conda-forge/protobuf-feedstock/issues/40),
which is fixed by this commit.