Refactor git_common config and die

git_common.py

 # Copyright 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.
 
 # Monkeypatch IMapIterator so that Ctrl-C can kill everything properly.
 # Derived from https://gist.github.com/aljungberg/626518
 import multiprocessing.pool
 from multiprocessing.pool import IMapIterator
 def wrapper(func):
   def wrap(self, timeout=None):
@@ skipping 263 matching lines @@
   how many times the decorated |function| is called."""
   def _inner_gen():
     yield function()
     while True:
       yield
   return _inner_gen().next
 
 
 ## Git functions
 
+def die(message, *args):
+  print >> sys.stderr, textwrap.dedent(message % args)
+  sys.exit(1)
+
 
 def blame(filename, revision=None, porcelain=False, *_args):
   command = ['blame']
   if porcelain:
     command.append('-p')
   if revision is not None:
     command.append(revision)
   command.extend(['--', filename])
   return run(*command)
 
 
 def branch_config(branch, option, default=None):
-  return config('branch.%s.%s' % (branch, option), default=default)
-
-
-def config_regexp(pattern):
-  if IS_WIN: # pragma: no cover
-    # this madness is because we call git.bat which calls git.exe which calls
-    # bash.exe (or something to that effect). Each layer divides the number of
-    # ^'s by 2.
-    pattern = pattern.replace('^', '^' * 8)
-  return run('config', '--get-regexp', pattern).splitlines()
+  return get_config('branch.%s.%s' % (branch, option), default=default)
 
 
 def branch_config_map(option):
   """Return {branch: <|option| value>} for all branches."""
   try:
     reg = re.compile(r'^branch\.(.*)\.%s$' % option)
-    lines = config_regexp(reg.pattern)
+    lines = get_config_regexp(reg.pattern)
     return {reg.match(k).group(1): v for k, v in (l.split() for l in lines)}
   except subprocess2.CalledProcessError:
     return {}
 
 
 def branches(*args):
   NO_BRANCH = ('* (no branch', '* (detached', '* (HEAD detached')
 
   key = 'depot-tools.branch-limit'
-  limit = 20
-  try:
-    limit = int(config(key, limit))
-  except ValueError:
-    pass
+  limit = get_config_int(key, 20)
 
   raw_branches = run('branch', *args).splitlines()
 
   num = len(raw_branches)
+
   if num > limit:
-    print >> sys.stderr, textwrap.dedent("""\
-    Your git repo has too many branches (%d/%d) for this tool to work well.
+    die("""\
+      Your git repo has too many branches (%d/%d) for this tool to work well.
 
-    You may adjust this limit by running:
+      You may adjust this limit by running:
       git config %s <new_limit>
-    """ % (num, limit, key))
-    sys.exit(1)
+
+      You may also try cleaning up your old branches by running:
+      git cl archive
+      """, num, limit, key)
 
   for line in raw_branches:
     if line.startswith(NO_BRANCH):
       continue
     yield line.split()[-1]
 
 
-def config(option, default=None):
+def get_config(option, default=None):
   try:
     return run('config', '--get', option) or default
   except subprocess2.CalledProcessError:
     return default
 
 
-def config_list(option):
+def get_config_int(option, default=0):
+  assert isinstance(default, int)
+  try:
+    return int(get_config(option, default))
+  except ValueError:
+    return default
+
+
+def get_config_list(option):
   try:
     return run('config', '--get-all', option).split()
   except subprocess2.CalledProcessError:
     return []
 
 
+def get_config_regexp(pattern):
+  if IS_WIN: # pragma: no cover
+    # this madness is because we call git.bat which calls git.exe which calls
+    # bash.exe (or something to that effect). Each layer divides the number of
+    # ^'s by 2.
+    pattern = pattern.replace('^', '^' * 8)
+  return run('config', '--get-regexp', pattern).splitlines()
+
+
 def current_branch():
   try:
     return run('rev-parse', '--abbrev-ref', 'HEAD')
   except subprocess2.CalledProcessError:
     return None
 
 
 def del_branch_config(branch, option, scope='local'):
   del_config('branch.%s.%s' % (branch, option), scope=scope)
 
@@ skipping 190 matching lines @@
   del_branch_config(branch, 'base')
   del_branch_config(branch, 'base-upstream')
 
 
 def repo_root():
   """Returns the absolute path to the repository root."""
   return run('rev-parse', '--show-toplevel')
 
 
 def root():
-  return config('depot-tools.upstream', 'origin/master')
+  return get_config('depot-tools.upstream', 'origin/master')
 
 
 @contextlib.contextmanager
 def less():  # pragma: no cover
   """Runs 'less' as context manager yielding its stdin as a PIPE.
 
   Automatically checks if sys.stdout is a non-TTY stream. If so, it avoids
   running less and just yields sys.stdout.
   """
   if not setup_color.IS_TTY:
@@ skipping 323 matching lines @@
                       ['HEAD'])
 
 
 def clone_file(repository, new_workdir, link, operation):
   if not os.path.exists(os.path.join(repository, link)):
     return
   link_dir = os.path.dirname(os.path.join(new_workdir, link))
   if not os.path.exists(link_dir):
     os.makedirs(link_dir)
   operation(os.path.join(repository, link), os.path.join(new_workdir, link))