Pass arguments to pylint child process via a pipe.

presubmit_canned_checks.py

 # Copyright (c) 2012 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.
 
 """Generic presubmit checks that can be reused by other presubmit checks."""
 
 import os as _os
 _HERE = _os.path.dirname(_os.path.abspath(__file__))
 
 
@@ skipping 635 matching lines @@
 
   # Copy the system path to the environment so pylint can find the right
   # imports.
   env = input_api.environ.copy()
   import sys
   env['PYTHONPATH'] = input_api.os_path.pathsep.join(sys.path)
 
   def run_lint(files):
     # We can't import pylint directly due to licensing issues, so we run
     # it in another process. Windows needs help running python files so we
-    # explicitly specify the interpreter to use.
+    # explicitly specify the interpreter to use. It also has limitations on
+    # the size of the command-line, so we pass arguments via a pipe.
     command = [input_api.python_executable,
-               input_api.os_path.join(_HERE, 'third_party', 'pylint.py')]
+               input_api.os_path.join(_HERE, 'third_party', 'pylint.py'),
+               '--args-on-stdin']
     try:
-      return input_api.subprocess.call(command + files + extra_args, env=env)
+      child = input_api.subprocess.Popen(command, env=env,
+          stdin=input_api.subprocess.PIPE)
+
+      # Dump the arguments to the child process via a pipe.
+      for filename in files:
+        child.stdin.write(filename + '\n')
+      for arg in extra_args:
+        child.stdin.write(arg + '\n')
+      child.stdin.close()
+
+      child.communicate()
+      return child.returncode
     except OSError:
       return 'Pylint failed!'
 
   result = None
   if not input_api.verbose:
     result = run_lint(sorted(files))
   else:
     for filename in sorted(files):
       print('Running pylint on %s' % filename)
       result = run_lint([filename]) or result
@@ skipping 261 matching lines @@
     results.extend(input_api.canned_checks.CheckSvnForCommonMimeTypes(
         input_api, output_api))
     snapshot("checking license")
     results.extend(input_api.canned_checks.CheckLicense(
         input_api, output_api, license_header, source_file_filter=sources))
     snapshot("checking was uploaded")
     results.extend(input_api.canned_checks.CheckChangeWasUploaded(
         input_api, output_api))
   snapshot("done")
   return results