Add "archive" command to git_cl.py.

git_cl.py

Index: git_cl.py
diff --git a/git_cl.py b/git_cl.py
index 35785ebdf0443e4c86784f4c820b0a7c71ca9103..bb2f112c7a81f344fe60c57e03a2bcbea56dfebf 100755
--- a/git_cl.py
+++ b/git_cl.py
@@ -2947,6 +2947,10 @@ def get_cl_statuses(changes, fine_grained, max_processes=None):
       fetch = lambda cl: (cl, cl.GetStatus())
       yield fetch(changes[0])
 
+      if len(changes) == 0:
+        # Exit early if there was only one branch to fetch.
+        return
+
       changes_to_fetch = changes[1:]
       pool = ThreadPool(
           min(max_processes, len(changes_to_fetch))
@@ -3073,6 +3077,68 @@ def upload_branch_deps(cl, args):
 
   return 0
 
+def CMDcleanup(parser, args):
+  """Archives and deletes branches associated with closed changelists."""
+  parser.add_option(
+      '-j', '--maxjobs', action='store', type=int,
+      help='The maximum number of jobs to use when retrieving review status')
+

[M-A Ruel, 2016/06/01 12:43:16]

remove empty line

[Kevin M, 2016/06/01 17:49:04]

Done.

+  parser.add_option(
+      '-f', action='store_true', dest='force', default=False,

[M-A Ruel, 2016/06/01 12:43:17]

instead of dest='force', add '--force'
remove default=False, default=None is good enough

[Kevin M, 2016/06/01 17:49:04]

Done.

+      help='Bypasses the confirmation prompt.')
+
+  auth.add_auth_options(parser)
+  options, args = parser.parse_args(args)
+  if args:
+    parser.error('Unsupported args: %s' % ' '.join(args))
+  auth_config = auth.extract_auth_config_from_options(options)
+
+  branches = RunGit(['for-each-ref', '--format=%(refname)', 'refs/heads'])
+  if not branches:
+    print 'No local branch found.'

[M-A Ruel, 2016/06/01 12:43:16]

Is that useful? Not sure it's worth printing anything.

[Kevin M, 2016/06/01 17:49:04]

Done.

+    return 0
+
+  print 'Finding all branches associated with closed issues...'

[M-A Ruel, 2016/06/01 12:43:17]

needed?

[Kevin M, 2016/06/01 17:49:04]

I added this to alleviate itchy ctrl-C fingers. This command is run
interactively, and it takes several seconds to get the statuses for all branches
on a well-used Git checkout. 

+  changes = [Changelist(branchref=b, auth_config=auth_config)
+              for b in branches.splitlines()]
+  alignment = max(5, max(len(c.GetBranch()) for c in changes))
+  statuses = get_cl_statuses(changes,
+                             fine_grained=True,
+                             max_processes=options.maxjobs)
+  proposal = [(cl.GetBranch(),

[M-A Ruel, 2016/06/01 12:43:16]

sort

[Kevin M, 2016/06/01 17:49:04]

Done.

+               'git-cl-closed-%s-%s' % (cl.GetIssue(), cl.GetBranch()))
+              for cl, status in statuses
+              if status == 'closed']
+
+  if len(proposal) == 0:

[M-A Ruel, 2016/06/01 12:43:16]

if not proposal:

[Kevin M, 2016/06/01 17:49:04]

Done.

+    print 'No branches with closed codereview issues found.'

[M-A Ruel, 2016/06/01 12:43:16]

needed?

[Kevin M, 2016/06/01 17:49:04]

I think so - the indirection from depending on CL status might make it unclear
as to why running this command is a no-op for some users.

+    return 0
+
+  current_branch = GetCurrentBranch()
+
+  print '\nBranches with closed issues that will be tagged and deleted:'
+  print '%*s | %s' % (alignment, 'Branch name', 'Archival tag name')
+  for next_item in proposal:
+    print '%*s   %s' % (alignment, next_item[0], next_item[1])
+
+  if any(branch == current_branch for branch, _ in proposal):
+    print ('You are currently on a branch \'%s\' which is associated with a '

[M-A Ruel, 2016/06/01 12:43:17]

no space between print and (), it's a function now.

[Kevin M, 2016/06/01 17:49:04]

Done.

[tandrii(chromium), 2016/06/02 21:35:30]

pedantic follow up: print is still a statement (easy proof: [print('')] gives
syntax error.

[M-A Ruel, 2016/06/03 13:06:39]

We'll eventually have to make this work in python 3, so I prefer to reduce the
churn in the new code.

[Kevin M, 2016/06/03 22:34:00]

Done.

+           'closed codereview issue, so cleanup cannot proceed. Please '
+           'checkout another branch and run this command again.') % \

[tandrii(chromium), 2016/06/01 09:53:17]

final nit: don't close ) here, then you don't need \ after %, 
and no need for parenthesis on around current_branch.

'checkout another branch and run this command again.' % 
current_branch)

[Kevin M, 2016/06/01 17:49:04]

Done.

+           (current_branch)
+    return 1
+
+  if not options.force:

[M-A Ruel, 2016/06/01 12:43:16]

I don't see why this is useful.

[Kevin M, 2016/06/01 17:49:04]

It makes this command suitable for running non-interactively e.g. as a command
sequence in an alias, or as part of a bash script.

Several other commands have a force option to skip the prompt, and for the
reasons stated above, I think this switch is a painless way to enable other uses
of this command.

+    if ask_for_data('\nProceed with deletion (Y/N)? ').lower() != 'y':
+      print 'Aborted.'
+      return 1
+
+  for branch, tagname in proposal:
+    RunGit(['tag', tagname, branch])

[M-A Ruel, 2016/06/01 12:43:16]

Why create a tag?

[Kevin M, 2016/06/01 17:49:04]

It preserves the local commit Git history for the branch, which makes it easy to
(e.g.) unearth useful commits that happened to be buried by subsequent commit
churn.

[tandrii(chromium), 2016/06/02 21:35:30]

Frankly, I don't think many devs would make use of these tags ever.

However, consider the branch deleting behavior of "git rebase-update". It is
badly surprising, even though it's actually quite useful and afaiu correct.
Informally, I've heard of quite a few engineers not using it exactly because of
this surprise. Heck, I was one of these engineers until I finally understood
what it does.

So, because of this, I think, creating a tag is that nice touch to keep our
developers calm, albeit at the cost of no gc being possible.

And that's why I ultimately support "git cl archive".

+    RunGit(['branch', '-D', branch])
+  print '\nJob\'s done!'
+
+  return 0
 
 def CMDstatus(parser, args):
   """Show status of changelists.