Avoid MSB8012 in GYP

pylib/gyp/generator/msvs.py

Index: pylib/gyp/generator/msvs.py
===================================================================
--- pylib/gyp/generator/msvs.py	(revision 1747)
+++ pylib/gyp/generator/msvs.py	(working copy)
@@ -1203,6 +1203,24 @@
   return out_file, vc_tool, msbuild_tool
 
 
+def _GetOutputTargetExt(spec):
+  """Returns the extension for this target, including the dot
+
+  If product_extension is specified, set target_extension to this to avoid
+  MSB8012, returns None otherwise. Ignores any target_extension settings in
+  the input files.
+
+  Arguments:
+    spec: The target dictionary containing the properties of the target.
+  Returns:
+    A string with the extension, or None
+  """
+  target_extension = spec.get('product_extension')
+  if target_extension:
+    return '.' + target_extension
+  return None
+
+
 def _GetDefines(config):
   """Returns the list of preprocessor definitions for this configuation.
 
@@ -2652,6 +2670,9 @@
     out_file = msbuild_settings[msbuild_tool].get('OutputFile')
     if out_file:
       msbuild_attributes['TargetPath'] = _FixPath(out_file)
+    target_ext = msbuild_settings[msbuild_tool].get('TargetExt')
+    if target_ext:
+      msbuild_attributes['TargetExt'] = target_ext
 
   return msbuild_attributes
 
@@ -2687,6 +2708,9 @@
     if attributes.get('TargetPath'):
       _AddConditionalProperty(properties, condition, 'TargetPath',
                               attributes['TargetPath'])
+    if attributes.get('TargetExt'):
+      _AddConditionalProperty(properties, condition, 'TargetExt',
+                              attributes['TargetExt'])
 
     if new_paths:
       _AddConditionalProperty(properties, condition, 'ExecutablePath',
@@ -2807,6 +2831,7 @@
   libraries = _GetLibraries(spec)
   library_dirs = _GetLibraryDirs(configuration)
   out_file, _, msbuild_tool = _GetOutputFilePathAndTool(spec, msbuild=True)
+  target_ext = _GetOutputTargetExt(spec)
   defines = _GetDefines(configuration)
   if converted:
     # Visual Studio 2010 has TR1
@@ -2844,6 +2869,9 @@
   if out_file:
     _ToolAppend(msbuild_settings, msbuild_tool, 'OutputFile', out_file,
                 only_if_unset=True)
+  if target_ext:
+    _ToolAppend(msbuild_settings, msbuild_tool, 'TargetExt', target_ext,
+                only_if_unset=True)
   # Add defines.
   _ToolAppend(msbuild_settings, 'ClCompile',
               'PreprocessorDefinitions', defines)