Merge pull request #2023 from odeke-em/fix-print-help-to-stdout

compiler/cli: PrintHelpText prints to stdout instead of stderr

src/google/protobuf/compiler/command_line_interface.cc

@@ -1452,7 +1452,7 @@ CommandLineInterface::InterpretArgument(const string& name,
 
 void CommandLineInterface::PrintHelpText() {
   // Sorry for indentation here; line wrapping would be uglier.
-  std::cerr <<
+  std::cout <<
 "Usage: " << executable_name_ << " [OPTION] PROTO_FILES\n"
 "Parse PROTO_FILES and generate output based on the options given:\n"
 "  -IPATH, --proto_path=PATH   Specify the directory in which to search for\n"
@@ -1499,7 +1499,7 @@ void CommandLineInterface::PrintHelpText() {
 "                              occupied fields numbers.\n"
       << std::endl;
   if (!plugin_prefix_.empty()) {
-    std::cerr <<
+    std::cout <<
 "  --plugin=EXECUTABLE         Specifies a plugin executable to use.\n"
 "                              Normally, protoc searches the PATH for\n"
 "                              plugins, but you may specify additional\n"
@@ -1515,7 +1515,7 @@ void CommandLineInterface::PrintHelpText() {
     // FIXME(kenton):  If the text is long enough it will wrap, which is ugly,
     //   but fixing this nicely (e.g. splitting on spaces) is probably more
     //   trouble than it's worth.
-    std::cerr << "  " << iter->first << "=OUT_DIR "
+    std::cout << "  " << iter->first << "=OUT_DIR "
               << string(19 - iter->first.size(), ' ')  // Spaces for alignment.
               << iter->second.help_text << std::endl;
   }

src/google/protobuf/compiler/command_line_interface_unittest.cc

@@ -156,6 +156,11 @@ class CommandLineInterfaceTest : public testing::Test {
   // Checks that the captured stdout is the same as the expected_text.
   void ExpectCapturedStdout(const string& expected_text);
 
+  // Checks that Run() returned zero and the stdout contains the given
+  // substring.
+  void ExpectCapturedStdoutSubstringWithZeroReturnCode(
+      const string& expected_substring);
+
   // Returns true if ExpectErrorSubstring(expected_substring) would pass, but
   // does not fail otherwise.
   bool HasAlternateErrorSubstring(const string& expected_substring);
@@ -488,6 +493,11 @@ void CommandLineInterfaceTest::ExpectCapturedStdout(
   EXPECT_EQ(expected_text, captured_stdout_);
 }
 
+void CommandLineInterfaceTest::ExpectCapturedStdoutSubstringWithZeroReturnCode(
+    const string& expected_substring) {
+  EXPECT_EQ(0, return_code_);
+  EXPECT_PRED_FORMAT2(testing::IsSubstring, expected_substring, captured_stdout_);
+}
 
 void CommandLineInterfaceTest::ExpectFileContent(
     const string& filename, const string& content) {
@@ -1703,11 +1713,11 @@ TEST_F(CommandLineInterfaceTest, GeneratorPluginNotAllowed) {
 TEST_F(CommandLineInterfaceTest, HelpText) {
   Run("test_exec_name --help");
 
-  ExpectErrorSubstringWithZeroReturnCode("Usage: test_exec_name ");
-  ExpectErrorSubstringWithZeroReturnCode("--test_out=OUT_DIR");
-  ExpectErrorSubstringWithZeroReturnCode("Test output.");
-  ExpectErrorSubstringWithZeroReturnCode("--alt_out=OUT_DIR");
-  ExpectErrorSubstringWithZeroReturnCode("Alt output.");
+  ExpectCapturedStdoutSubstringWithZeroReturnCode("Usage: test_exec_name ");
+  ExpectCapturedStdoutSubstringWithZeroReturnCode("--test_out=OUT_DIR");
+  ExpectCapturedStdoutSubstringWithZeroReturnCode("Test output.");
+  ExpectCapturedStdoutSubstringWithZeroReturnCode("--alt_out=OUT_DIR");
+  ExpectCapturedStdoutSubstringWithZeroReturnCode("Alt output.");
 }
 
 TEST_F(CommandLineInterfaceTest, GccFormatErrors) {