Simplify and optimize FindCycles

test/errors/gyptest-errors.py

 #!/usr/bin/env python
 
 # 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.
 
 """
 Test that two targets with the same name generates an error.
 """
 
@@ skipping 21 matching lines @@
 stderr = ('gyp: rule bar exists in duplicate, target '
           '.*duplicate_rule.gyp:foo#target\n')
 test.run_gyp('duplicate_rule.gyp', status=1, stderr=stderr,
              match=TestCmd.match_re)
 
 stderr = ("gyp: Key 'targets' repeated at level 1 with key path '' while "
           "reading .*duplicate_node.gyp.*")
 test.run_gyp('duplicate_node.gyp', '--check', status=1, stderr=stderr,
              match=TestCmd.match_re_dotall)
 
+stderr = (".*target0.*target1.*target2.*target0.*")
+test.run_gyp('dependency_cycle.gyp', status=1, stderr=stderr,
+             match=TestCmd.match_re_dotall)
+
+stderr = (".*file_cycle0.*file_cycle1.*file_cycle0.*")
+test.run_gyp('file_cycle0.gyp', status=1, stderr=stderr,
+             match=TestCmd.match_re_dotall)
+
 stderr = 'gyp: Duplicate basenames in sources section, see list above\n'
 test.run_gyp('duplicate_basenames.gyp', status=1, stderr=stderr)
 
 # Check if '--no-duplicate-basename-check' works.
 if ((test.format == 'make' and sys.platform == 'darwin') or
     (test.format == 'msvs' and
         int(os.environ.get('GYP_MSVS_VERSION', 2010)) < 2010)):
   stderr = 'gyp: Duplicate basenames in sources section, see list above\n'
   test.run_gyp('duplicate_basenames.gyp', '--no-duplicate-basename-check',
                status=1, stderr=stderr)
 else:
   test.run_gyp('duplicate_basenames.gyp', '--no-duplicate-basename-check')
 
 stderr = ("gyp: Dependency '.*missing_dep.gyp:missing.gyp#target' not found "
           "while trying to load target .*missing_dep.gyp:foo#target\n")
 test.run_gyp('missing_dep.gyp', status=1, stderr=stderr,
              match=TestCmd.match_re)
 
 test.pass_test()