Don't be pedantic about .gclient file for non-mutating commands.

gclient.py

 #!/usr/bin/env python
 # 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.
 
 """Meta checkout manager supporting both Subversion and GIT."""
 # Files
 #   .gclient      : Current client configuration, written by 'config' command.
 #                   Format is a Python script defining 'solutions', a list whose
 #                   entries each are maps binding the strings "name" and "url"
@@ skipping 1306 matching lines @@
   def RunOnDeps(self, command, args, ignore_requirements=False, progress=True):
     """Runs a command on each dependency in a client and its dependencies.
 
     Args:
       command: The command to use (e.g., 'status' or 'diff')
       args: list of str - extra arguments to add to the command line.
     """
     if not self.dependencies:
       raise gclient_utils.Error('No solution specified')
 
-    self._CheckConfig()
-
     revision_overrides = {}
     # It's unnecessary to check for revision overrides for 'recurse'.
     # Save a few seconds by not calling _EnforceRevisions() in that case.
     if command not in ('diff', 'recurse', 'runhooks', 'status'):
+      self._CheckConfig()
       revision_overrides = self._EnforceRevisions()
     pm = None
     # Disable progress for non-tty stdout.
     if (sys.stdout.isatty() and not self._options.verbose and progress):
       if command in ('update', 'revert'):
         pm = Progress('Syncing projects', 1)
       elif command == 'recurse':
         pm = Progress(' '.join(args), 1)
     work_queue = gclient_utils.ExecutionQueue(
         self._options.jobs, pm, ignore_requirements=ignore_requirements,
@@ skipping 723 matching lines @@
     print >> sys.stderr, 'Error: %s' % str(e)
     return 1
   finally:
     gclient_utils.PrintWarnings()
 
 
 if '__main__' == __name__:
   sys.exit(Main(sys.argv[1:]))
 
 # vim: ts=2:sw=2:tw=80:et: