depot_tools: Add git svn find-rev for safesync_url parsing (commonly LKGR link).

gclient_scm.py

Index: gclient_scm.py
===================================================================
--- gclient_scm.py	(revision 107937)
+++ gclient_scm.py	(working copy)
@@ -476,6 +476,24 @@
       files = self._Capture(['diff', '--name-only', merge_base]).split()
       file_list.extend([os.path.join(self.checkout_path, f) for f in files])
 
+  def FindSafesyncRev(self, rev):
+    # If this doesn't look like a Subversion revision (just numbers), pass it

[M-A Ruel, 2011/10/31 13:46:51]

Please add a proper docstring.

[Dan Beam, 2011/11/06 07:34:08]

Done.

+    # back as maybe somebody's made a git LKGR page? TODO(dbeam): Test if sha1?
+    if not rev.isdigit():

[M-A Ruel, 2011/10/31 13:46:51]

Also look for "or len(rev) > 7"
We'll revision once we have more than 9999999 revisions.

[Dan Beam, 2011/11/06 07:34:08]

Done.

+      return rev
+    # This probably only works if using git-svn, as the LKGR is only based on
+    # SVN revisions at the moment.
+    if not scm.GIT.IsGitSvn(cwd=self.checkout_path):
+      help_url = ''.join(['http://code.google.com/p/chromium/wiki/UsingNewGit',
+                          '#Initial_checkout'])
+      print('WARNING: Safesync URLs currently require a git-svn remote.\n'
+            '         Please add a git-svn remote or remove the safesync_url.\n'
+            '         %s\n' % help_url)
+      return ''

[M-A Ruel, 2011/10/31 13:46:51]

No, '01234567' could still be a valid short hash. It would be nice to verify the
hash is valid. Something like
git rev-parse $(rev) should return a valid hash.

In any case, silently dropping the value is not a valid option.

[Dan Beam, 2011/11/06 07:34:08]

Done.

+    # Otherwise, if using git-svn, let's search the index for a sha1 that
+    # matches this Subversion revision (the current LKGR format).
+    return scm.GIT.GetSha1ForSvnRev(cwd=self.checkout_path, rev=rev)
+
   def FullUrlForRelativeUrl(self, url):
     # Strip from last '/'
     # Equivalent to unix basename
@@ -986,6 +1004,20 @@
     else:
       self._RunAndGetFileList(command, options, file_list)
 
+  # pylint: disable-msg=r0201
+  def FindSafesyncRev(self, rev):

[M-A Ruel, 2011/10/31 13:46:51]

Make it a @staticmethod instead of disabling the warning.

Also, just return rev without touching it.

It could be a {DATE}, BASE, HEAD, COMMITTED, PREV, or god who knows.

You could verify that the revision is valid with
svn info -r $(rev) $(url) but I don't think it's useful to do a network request
at this point.

[Dan Beam, 2011/11/06 07:34:08]

Done.

+    # If the SCM currently being used is Subversion, and it appears we were
+    # passed a Subversion |rev| number, just return the same |rev|.
+    if rev.isdigit():
+      return rev
+    # If the SCM currently being used is Subversion, but we receieved a
+    # non-numeric response, ignore the safesync_url's response in this case.
+    print('WARNING: The content of safesync_url is currently assumed to be\n'
+          '         only a Subversion revision when using a Subversion check\n'
+          '         out, but the response was not a number.\n'
+          '         Ignoring for now.\n')
+    return ''
+
   def FullUrlForRelativeUrl(self, url):
     # Find the forth '/' and strip from there. A bit hackish.
     return '/'.join(self.url.split('/')[:4]) + url