Add support to check if the url has changed for a git dep and create a new clone.

gclient_scm.py

Index: gclient_scm.py
===================================================================
--- gclient_scm.py	(revision 79277)
+++ gclient_scm.py	(working copy)
@@ -186,6 +186,27 @@
       verbose = ['--verbose']
       printed_path = True
 
+    # See if the url has changed
+    current_url = self._Capture(['config', 'remote.origin.url'])
+    if current_url != url:
+      print('_____ switching %s to a new upstream' % self.relpath)
+      # Make sure it's clean
+      self._CheckClean(rev_str)
+      # Switch over to the new upstream
+      commands = [
+        (['remote', 'set-url', 'origin', url], None),
+        (['fetch', 'origin', '--prune'], '--quiet'),
+        (['reset', '--hard', 'origin/master'], '-q'),
+      ]
+      for cmd, quiet_arg in commands:

[M-A Ruel, 2011/03/24 17:17:02]

It's funny but the following is still less lines (6 vs 9) and more readable
IMHO:

self._Run(['remote', 'set-url', 'origin', url])
quiet = []
if not options.verbose:
  quiet = ['--quiet']
self._Run(['fetch', 'origin', '--prune'] + quiet)
self._Run(['reset', '--hard', 'origin/master'] + quiet)

cwd=self.checkout_path is not necessary since it's set as default.

[TVL, 2011/03/24 17:43:11]

Done.  (help didn't list --quiet as valid for reset, only listed -q)

+        if not options.verbose and quiet_arg:
+          cmd.append(quiet_arg)
+        self._Run(cmd, options, cwd=self.checkout_path)
+      # List the tree in the file list
+      files = self._Capture(['ls-files']).split()

[M-A Ruel, 2011/03/24 17:17:02]

splitlines() ?

[TVL, 2011/03/24 17:43:11]

I just copied what 222-223 do for a fresh clone, should both change?

+      file_list.extend([os.path.join(self.checkout_path, f) for f in files])
+      return
+
     if revision.startswith('refs/heads/'):
       rev_type = "branch"
     elif revision.startswith('origin/'):