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 108803)
+++ gclient_scm.py	(working copy)
@@ -476,6 +476,35 @@
       files = self._Capture(['diff', '--name-only', merge_base]).split()
       file_list.extend([os.path.join(self.checkout_path, f) for f in files])
 
+  @staticmethod
+  def FindSafesyncRev(cwd, rev, options):

[M-A Ruel, 2011/11/08 14:29:20]

Note that this function has nothing to do with 'safe sync' in the first place.
It's simply a 'Revision format conversion function'. Try to change the name to
what the function actually does.

[Dan Beam, 2011/11/09 10:31:15]

Done.

+    """Find a useful safesync revision for this repository. If SCM is git-svn

[M-A Ruel, 2011/11/08 14:29:20]

Finds

[Dan Beam, 2011/11/09 10:31:15]

Done.

+       and the head revision is less than |rev|, git svn fetch will be

[M-A Ruel, 2011/11/08 14:29:20]

style nit: In general we strive for the docstring to have the format:
"""Single line summary.

Long description aligned at +0 compared to the """.
Blah blah.
"""

[Dan Beam, 2011/11/09 10:31:15]

Done.

+       called on the source."""
+    sha1 = None
+    # As an optimization, only verify an SVN revision as [0-9]{1,6} for now so
+    # we avoiding making a network request.
+    if (scm.GIT.IsGitSvn(cwd=cwd) and
+        rev.isdigit() and len(rev) < 7):
+      local_head = scm.GIT.GetGitSvnHeadRev(cwd=cwd)
+      if not local_head or local_head < int(rev):
+        if options.verbose:
+          print('Running git svn fetch. This might take a while.\n')
+        scm.GIT.Capture(['svn', 'fetch'], cwd=cwd)
+      sha1 = scm.GIT.GetSha1ForSvnRev(cwd=cwd, rev=rev)
+    else:
+      sha1 = scm.GIT.VerifyRevisionFormat(cwd=cwd, rev=rev)
+    if not sha1:
+      # If we didn't find anything, show a warning.

[M-A Ruel, 2011/11/08 14:29:20]

Are you sure a warning is a good idea? It'll get lost in the noise, I'd rather
abort instead.

I don't have a strong opinion, I just don't see an argument to not abort.

[Dan Beam, 2011/11/09 10:31:15]

Done.

+      help_url = ''.join(['http://code.google.com/p/chromium/wiki/UsingNewGit',
+                          '#Initial_checkout'])
+      print('WARNING: Safesync URLs with a git checkout currently require a\n'
+            '         git-svn remote or a safesync_url that provides git\n'
+            '         sha1s. Please add a git-svn remote or change your\n'
+            '         safesync_url.\n'
+            '         %s\n' % help_url)
+    return sha1
+
   def FullUrlForRelativeUrl(self, url):
     # Strip from last '/'
     # Equivalent to unix basename
@@ -991,6 +1020,17 @@
     else:
       self._RunAndGetFileList(command, options, file_list)
 
+  @staticmethod
+  def FindSafesyncRev(cwd, rev, options):
+    """Find a useful safesync revision for this repository."""

[M-A Ruel, 2011/11/08 14:29:20]

Finds

[Dan Beam, 2011/11/09 10:31:15]

Done.

+    if scm.SVN.VerifyRevisionFormat(cwd=cwd, rev=rev):
+      return rev
+    # Invalid revision format.
+    print('WARNING: The content of safesync_url didn\'t look like a valid\n'

[M-A Ruel, 2011/11/08 14:29:20]

Same as line 498. Either always return rev silently or abort?

[Dan Beam, 2011/11/09 10:31:15]

Done.

+          '         Subversion revision.  Please check your safesync_url is\n'
+          '         correct. Ignoring for now.\n')
+    return None
+
   def FullUrlForRelativeUrl(self, url):
     # Find the forth '/' and strip from there. A bit hackish.
     return '/'.join(self.url.split('/')[:4]) + url