Fixed version of https://codereview.chromium.org/748793002

pylib/gyp/xcodeproj_file.py

 # Copyright (c) 2012 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.
 
 """Xcode project file generator.
 
 This module is both an Xcode project file generator and a documentation of the
 Xcode project file format.  Knowledge of the project file format was gained
 based on extensive experience with Xcode, and by making changes to projects in
 Xcode.app and observing the resultant changes in the associated project files.
@@ skipping 2731 matching lines @@
       dir_path = project_ref._properties['path']
       product_group._hashables.extend(dir_path)
 
     return [product_group, project_ref]
 
   def _AllSymrootsUnique(self, target, inherit_unique_symroot):
     # Returns True if all configurations have a unique 'SYMROOT' attribute.
     # The value of inherit_unique_symroot decides, if a configuration is assumed
     # to inherit a unique 'SYMROOT' attribute from its parent, if it doesn't
     # define an explicit value for 'SYMROOT'.
+    symroots = self._DefinedSymroots(target)
     for s in self._DefinedSymroots(target):
       if (s is not None and not self._IsUniqueSymrootForTarget(s) or
           s is None and not inherit_unique_symroot):
         return False
-    return True
+    return True if symroots else return inherit_unique_symroot
 
   def _DefinedSymroots(self, target):
     # Returns all values for the 'SYMROOT' attribute defined in all
     # configurations for this target. If any configuration doesn't define the
     # 'SYMROOT' attribute, None is added to the returned set. If all
     # configurations don't define the 'SYMROOT' attribute, an empty set is
     # returned.
     config_list = target.GetProperty('buildConfigurationList')
     symroots = set()
     for config in config_list.GetProperty('buildConfigurations'):
@@ skipping 160 matching lines @@
       self._XCPrint(file, 0, '/* Begin ' + class_name + ' section */\n')
       for object in sorted(objects_by_class[class_name],
                            cmp=lambda x, y: cmp(x.id, y.id)):
         object.Print(file)
       self._XCPrint(file, 0, '/* End ' + class_name + ' section */\n')
 
     if self._should_print_single_line:
       self._XCPrint(file, 0, '}; ')
     else:
       self._XCPrint(file, 1, '};\n')