Changes ninja generator to only output empty names if not already output

pylib/gyp/generator/ninja.py

 # Copyright (c) 2013 Google Inc. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import collections
 import copy
 import hashlib
 import json
 import multiprocessing
 import os.path
@@ skipping 2134 matching lines @@
   all_outputs = set()
 
   # target_outputs is a map from qualified target name to a Target object.
   target_outputs = {}
   # target_short_names is a map from target short name to a list of Target
   # objects.
   target_short_names = {}
 
   # short name of targets that were skipped because they didn't contain anything
   # interesting.
-  empty_target_names = []
+  # NOTE: there may be overlap between this an non_empty_target_names.
+  empty_target_names = set()
+
+  # Set of non-empty short target names.
+  # NOTE: there may be overlap between this an empty_target_names.
+  non_empty_target_names = set()
 
   for qualified_target in target_list:
     # qualified_target is like: third_party/icu/icu.gyp:icui18n#target
     build_file, name, toolset = \
         gyp.common.ParseQualifiedTarget(qualified_target)
 
     this_make_global_settings = data[build_file].get('make_global_settings', [])
     assert make_global_settings == this_make_global_settings, (
         "make_global_settings needs to be the same for all targets. %s vs. %s" %
         (this_make_global_settings, make_global_settings))
@@ skipping 24 matching lines @@
         ninja_file.write(ninja_output.getvalue())
       ninja_output.close()
       master_ninja.subninja(output_file)
 
     if target:
       if name != target.FinalOutput() and spec['toolset'] == 'target':
         target_short_names.setdefault(name, []).append(target)
       target_outputs[qualified_target] = target
       if qualified_target in all_targets:
         all_outputs.add(target.FinalOutput())
+      non_empty_target_names.add(name)
     else:
-      empty_target_names.append(name)
+      empty_target_names.add(name)
 
   if target_short_names:
     # Write a short name to build this target.  This benefits both the
     # "build chrome" case as well as the gyp tests, which expect to be
     # able to run actions and build libraries by their short name.
     master_ninja.newline()
     master_ninja.comment('Short names for targets.')
     for short_name in target_short_names:
       master_ninja.build(short_name, 'phony', [x.FinalOutput() for x in
                                                target_short_names[short_name]])
 
+  # Write phony targets for any empty targets that weren't written yet. As
+  # short names are  not necessarily unique only do this for short names that
+  # haven't already been output for another target.
+  empty_target_names = empty_target_names - non_empty_target_names
   if empty_target_names:
-    # Write out any targets that were skipped because they didn't contain
-    # anything interesting. This way the targets can still be built without
-    # causing build errors.
     master_ninja.newline()
     master_ninja.comment('Empty targets (output for completeness).')
     for name in sorted(empty_target_names):
       master_ninja.build(name, 'phony')
 
   if all_outputs:
     master_ninja.newline()
     master_ninja.build('all', 'phony', list(all_outputs))
     master_ninja.default(generator_flags.get('default_target', 'all'))
 
@@ skipping 42 matching lines @@
           arglists.append(
               (target_list, target_dicts, data, params, config_name))
         pool.map(CallGenerateOutputForConfig, arglists)
       except KeyboardInterrupt, e:
         pool.terminate()
         raise e
     else:
       for config_name in config_names:
         GenerateOutputForConfig(target_list, target_dicts, data, params,
                                 config_name)