Modify roll_dep's commit message

roll_dep.py

 #!/usr/bin/env python
 # Copyright (c) 2014 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.
 
 """This scripts takes the path to a dep and an svn revision, and updates the
 parent repo's DEPS file with the corresponding git revision.  Sample invocation:
 
 [chromium/src]$ roll-dep third_party/WebKit 12345
 
 After the script completes, the DEPS file will be dirty with the new revision.
 The user can then:
 
 $ git add DEPS
 $ git commit
 """
 
 import ast
 import os
 import re
 import sys
 
 from itertools import izip
 from subprocess import Popen, PIPE
 from textwrap import dedent
 
 
 SHA1_RE = re.compile('^[a-fA-F0-9]{40}$')
 GIT_SVN_ID_RE = re.compile('^git-svn-id: .*@([0-9]+) .*$')
+ROLL_DESCRIPTION_STR = '''Roll %s from %s to %s
+
+Summary of changes available at:
+%s
+'''
+
+
+def shorten_dep_path(dep):
+  """Shorten the given dep path if necessary."""
+  while len(dep) > 31:
+    dep = '.../' + dep.lstrip('./').partition('/')[2]
+  return dep
 
 
 def posix_path(path):
   """Convert a possibly-Windows path to a posix-style path."""
   (_, path) = os.path.splitdrive(path)
   return path.replace(os.sep, '/')
 
 
 def platform_path(path):
   """Convert a path to the native path format of the host OS."""
@@ skipping 201 matching lines @@
       'Could not find definition of "%s" var in DEPS file.' % var_name)
   val_node = vars_node.values[var_idx]
   return update_node(deps_lines, deps_ast, val_node, git_revision)
 
 
 def generate_commit_message(deps_section, dep_name, new_rev):
   (url, _, old_rev) = deps_section[dep_name].partition('@')
   if url.endswith('.git'):
     url = url[:-4]
   url += '/+log/%s..%s' % (old_rev[:12], new_rev[:12])
-  return dedent('''\
-      Rolled %s
-          from revision %s
-          to revision %s
-      Summary of changes available at:
-          %s\n''' % (dep_name, old_rev, new_rev, url))
+  return dedent(ROLL_DESCRIPTION_STR % (
+      shorten_dep_path(dep_name), old_rev[:12], new_rev[:12], url))
 
 def update_deps_entry(deps_lines, deps_ast, value_node, new_rev, comment):
   line_idx = update_node(deps_lines, deps_ast, value_node, new_rev)
   (content, _, _) = deps_lines[line_idx].partition('#')
   if comment:
     deps_lines[line_idx] = '%s # %s' % (content.rstrip(), comment)
   else:
     deps_lines[line_idx] = content.rstrip()
 
 def update_deps(soln_path, dep_name, new_rev, comment):
@@ skipping 53 matching lines @@
   soln = get_solution(gclient_root, dep_path)
   soln_path = os.path.relpath(os.path.join(gclient_root, soln['name']))
   dep_name = posix_path(os.path.relpath(dep_path, gclient_root))
   (git_rev, svn_rev) = get_git_revision(dep_path, revision)
   comment = ('from svn revision %s' % svn_rev) if svn_rev else None
   assert git_rev, 'Could not find git revision matching %s.' % revision
   return update_deps(soln_path, dep_name, git_rev, comment)
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv[1:]))