Polymer: Update find_unused_elements.py

third_party/polymer/v1_0/find_unused_elements.py

 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Identifies Polymer elements that downloaded but not used by Chrome.
 
 Only finds "first-order" unused elements; re-run after removing unused elements
 to check if other elements have become unused.
 """
 
@@ skipping 40 matching lines @@
 
     Returns:
       A string consisting of the minified file contents with comments and grit
       directives removed.
     """
     with open(filename) as f:
       text = f.read()
     text = re.sub('<if .*?>', '', text, flags=re.IGNORECASE)
     text = re.sub('</if>', '', text, flags=re.IGNORECASE)
 
     proc = subprocess.Popen(['uglifyjs', filename], stdout=subprocess.PIPE)

[dpapad, 2017/06/02 18:19:26]

Actually there is more issues with this script. It assumes that uglifyjs is
installed globally, or in this folder, instead of grabbing it from third_party.
Will attempt to update as part of the same CL. It currently throws following
error:

Traceback (most recent call last):
  File "find_unused_elements.py", line 151, in <module>
    UnusedElementsDetector().Run()
  File "find_unused_elements.py", line 106, in Run
    not self.__IsImported(element, relevant_src_dirs)):
  File "find_unused_elements.py", line 145, in __IsImported
    os.path.join(dirpath, filename))):
  File "find_unused_elements.py", line 78, in __StripComments
    text = UnusedElementsDetector.__StripJsComments(filename)
  File "find_unused_elements.py", line 61, in __StripJsComments
    proc = subprocess.Popen(['uglifyjs', filename], stdout=subprocess.PIPE)
  File "/usr/lib/python2.7/subprocess.py", line 710, in __init__
    errread, errwrite)
  File "/usr/lib/python2.7/subprocess.py", line 1327, in _execute_child
    raise child_exception
OSError: [Errno 2] No such file or directory

[dpapad, 2017/06/02 19:01:53]

Addressed in latest patch.

     return proc.stdout.read()
 
   @staticmethod
   def __StripComments(filename):
     """Returns the contents of a JavaScript or HTML file with comments removed.
 
     Args:
       filename: The name of the file to read.
 
     Returns:
@@ skipping 54 matching lines @@
       for (dirpath, _, filenames) in os.walk(path):
         # Ignore the element's own files.
         if dirpath.startswith(os.path.join(
             self.__COMPONENTS_DIR, element_dir)):
           continue
 
         for filename in filenames:
           if not filename.endswith('.html') and not filename.endswith('.js'):
             continue
 
-          # Skip generated files that may include the element source.
-          if filename in ('crisper.js', 'vulcanized.html',
-                          'app.crisper.js', 'app.vulcanized.html'):
-            continue
-
           with open(os.path.join(dirpath, filename)) as f:
             text = f.read()
           if not re.search('/%s/' % element_dir, text):
             continue
 
           # Check the file again, ignoring comments (e.g. example imports and
           # scripts).
           if re.search('/%s' % element_dir,
                        self.__StripComments(
                          os.path.join(dirpath, filename))):
             return True
     return False
 
 
 if __name__ == '__main__':
   UnusedElementsDetector().Run()