MSVS: Fix to ensure that actions are re-run when the action command changes

pylib/gyp/generator/msvs.py

Index: pylib/gyp/generator/msvs.py
diff --git a/pylib/gyp/generator/msvs.py b/pylib/gyp/generator/msvs.py
index c61142ea9748f9e6975d8cfb8ee3898be5c3983b..72896adede97fa3f927251cabfd3a187d5abdfa3 100644
--- a/pylib/gyp/generator/msvs.py
+++ b/pylib/gyp/generator/msvs.py
@@ -880,6 +880,8 @@ def _GenerateMSVSProject(project, options, version, generator_flags):
   project_dir = os.path.split(project.path)[0]
   gyp_path = _NormalizedSource(project.build_file)
   relative_path_of_gyp_file = gyp.common.RelativePath(gyp_path, project_dir)
+  relative_path_of_vcproj_file = \
+      gyp.common.RelativePath(project.path, project_dir)
 
   config_type = _GetMSVSConfigurationType(spec, project.build_file)
   for config_name, config in spec['configurations'].iteritems():
@@ -905,7 +907,8 @@ def _GenerateMSVSProject(project, options, version, generator_flags):
 
   _AddToolFilesToMSVS(p, spec)
   _HandlePreCompiledHeaders(p, sources, spec)
-  _AddActions(actions_to_add, spec, relative_path_of_gyp_file)
+  _AddActions(actions_to_add, spec, relative_path_of_gyp_file,
+              relative_path_of_vcproj_file)
   _AddCopies(actions_to_add, spec)
   _WriteMSVSUserFile(project.path, version, spec)
 
@@ -1441,13 +1444,23 @@ def _HandlePreCompiledHeaders(p, sources, spec):
     DisableForSourceTree(sources)
 
 
-def _AddActions(actions_to_add, spec, relative_path_of_gyp_file):
+def _AddActions(actions_to_add, spec, relative_path_of_gyp_file,
+                relative_path_of_vcproj_file):
   # Add actions.
   actions = spec.get('actions', [])
   for a in actions:
     cmd = _BuildCommandLineForRule(spec, a, has_input_path=False)
     # Attach actions to the gyp file if nothing else is there.
     inputs = a.get('inputs') or [relative_path_of_gyp_file]
+    if relative_path_of_vcproj_file:
+      # Additionally, on MSVS 2008, we mark the project file as a
+      # dependency of the action so that when the action's command
+      # changes, the action will get re-run even if no other input
+      # files change.  However, this will re-run unchanged actions
+      # unnecessarily when the project file changes.  This is not
+      # necessary on MSVS 2010 which handles command changes for us.
+      # TODO(mseaborn): Detect changes at a finer granularity.
+      inputs = inputs + [relative_path_of_vcproj_file]
     # Add the action.
     _AddActionStep(actions_to_add,
                    inputs=inputs,
@@ -2892,9 +2905,6 @@ def _GenerateMSBuildProject(project, options, version, generator_flags):
   if msbuildproj_dir and not os.path.exists(msbuildproj_dir):
     os.makedirs(msbuildproj_dir)
   # Prepare list of sources and excluded sources.
-  gyp_path = _NormalizedSource(project.build_file)
-  relative_path_of_gyp_file = gyp.common.RelativePath(gyp_path, project_dir)
-
   gyp_file = os.path.split(project.build_file)[1]
   sources, excluded_sources = _PrepareListOfSources(spec, gyp_file)
   # Add rules.
@@ -2912,7 +2922,7 @@ def _GenerateMSBuildProject(project, options, version, generator_flags):
                                                 project_dir, sources,
                                                 excluded_sources,
                                                 list_excluded))
-  _AddActions(actions_to_add, spec, project.build_file)
+  _AddActions(actions_to_add, spec, project.build_file, None)
   _AddCopies(actions_to_add, spec)
 
   # NOTE: this stanza must appear after all actions have been decided.