Clearer help in gclient-new-workdir.py

gclient-new-workdir.py

 #!/usr/bin/env python
 # Copyright 2013 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.
 #
 # Usage:
 #    gclient-new-workdir.py <repository> <new_workdir> [<branch>]
 #
 
 import os
 import shutil
 import subprocess
 import sys
+import textwrap
+
+
+def print_err(msg):
+  print >> sys.stderr, msg
 
 
 def parse_options(argv):
-  assert not sys.platform.startswith("win")
+  if sys.platform == 'win32':
+    print_err(
+      'This script cannot run on Windows because it uses symlinks.')
+    sys.exit(1)
 
   if len(argv) != 3:
-    print("usage: gclient-new-workdir.py <repository> <new_workdir>")
+    usage_msg = '''\
+    usage: %s <repository> <new_workdir>
+
+    Clone an existing gclient directory, taking care of all sub-repositories
+    Works similarly to 'git new-workdir'.
+
+    <repository> must be a absolute path
+    <new_workdir> must not exist
+    ''' % os.path.basename(argv[0])
+    print(textwrap.dedent(usage_msg))
     sys.exit(1)

[iannucci, 2013/11/13 20:29:10]

move this whole if statement body into a usage() function which prints usage and
quits w/ 1. The usage function should take an optional msg argument, and print
that on stderr before printing usage. usage should probably be printed on stderr
as well, right?

[pgervais, 2013/11/13 23:27:54]

It depends if execution of usage() is triggered by a -h switch or by invalid
parameters. Since there is not -h option here, I suppose printing to stderr is
fine.

 
-  repository = argv[1]
+  repository = os.path.abspath(argv[1])
   new_workdir = argv[2]
 
   if not os.path.exists(repository):
-    print("Repository does not exist: " + repository)
+    print_err('Repository does not exist: ' + repository)
     sys.exit(1)

[iannucci, 2013/11/13 20:29:10]

then these can become usage(...) calls

 
   if os.path.exists(new_workdir):
-    print("New workdir already exists: " + new_workdir)
+    print_err('New workdir already exists: ' + new_workdir)
     sys.exit(1)
 
   return repository, new_workdir
 
 
 def main(argv):
   repository, new_workdir = parse_options(argv)
 
-  gclient = os.path.join(repository, ".gclient")
+  gclient = os.path.join(repository, '.gclient')
   if not os.path.exists(gclient):
-    print("No .gclient file: " + gclient)
+    print_err('No .gclient file: ' + gclient)
 
-  gclient_entries = os.path.join(repository, ".gclient_entries")
-  if not os.path.exists(gclient_entries):
-    print("No .gclient_entries file: " + gclient_entries)
-
-  os.mkdir(new_workdir)
-  os.symlink(gclient, os.path.join(new_workdir, ".gclient"))
-  os.symlink(gclient_entries, os.path.join(new_workdir, ".gclient_entries"))
+  os.makedirs(new_workdir)
+  os.symlink(gclient, os.path.join(new_workdir, '.gclient'))

[iannucci, 2013/11/13 20:29:10]

I'm assuming you tried it out and this does, in fact, work (i.e. gclient
generates a new entries file)

[pgervais, 2013/11/13 23:27:54]

Yes it does (on gclient sync at least)

 
   for root, dirs, _ in os.walk(repository):
-    if ".git" in dirs:
+    if '.git' in dirs:
       workdir = root.replace(repository, new_workdir, 1)
-      make_workdir(os.path.join(root, ".git"),
-                   os.path.join(workdir, ".git"))
+      make_workdir(os.path.join(root, '.git'),
+                   os.path.join(workdir, '.git'))
 
 
 def make_workdir(repository, new_workdir):
-  print("Creating: " + new_workdir)
+  print('Creating: ' + new_workdir)
   os.makedirs(new_workdir)
 
   GIT_DIRECTORY_WHITELIST = [
-    "config",
-    "info",
-    "hooks",
-    "logs/refs",
-    "objects",
-    "packed-refs",
-    "refs",
-    "remotes",
-    "rr-cache",
-    "svn"
+    'config',
+    'info',
+    'hooks',
+    'logs/refs',
+    'objects',
+    'packed-refs',
+    'refs',
+    'remotes',
+    'rr-cache',
+    'svn'
   ]
 
   for entry in GIT_DIRECTORY_WHITELIST:
     make_symlink(repository, new_workdir, entry)
 
-  shutil.copy2(os.path.join(repository, "HEAD"),
-               os.path.join(new_workdir, "HEAD"))
-  subprocess.check_call(["git", "checkout", "-f"],
-                        cwd=new_workdir.rstrip(".git"))
+  shutil.copy2(os.path.join(repository, 'HEAD'),
+               os.path.join(new_workdir, 'HEAD'))
+  subprocess.check_call(['git', 'checkout', '-f'],
+                        cwd=new_workdir.rstrip('.git'))
 
 
 def make_symlink(repository, new_workdir, link):
   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)
   os.symlink(os.path.join(repository, link), os.path.join(new_workdir, link))
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv))