Improve "dcommit in git repo" error message.

R=agable@chromium.org, iannucci@chromium.org

Review URL: https://codereview.chromium.org/1135563005.

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@295609 0039d316-1c4b-4281-b951-d872f2087c98

git_auto_svn.py

@@ -23,7 +23,7 @@ import subprocess2
 from git_common import run as run_git
 from git_common import run_stream as run_git_stream
 from git_common import set_config, root, ROOT
-from git_footers import parse_footers, get_unique, GIT_SVN_ID_PATTERN
+from git_footers import get_footer_svn_id
 
 
 SVN_EXE = ROOT+'\\svn.bat' if sys.platform.startswith('win') else 'svn'
@@ -58,14 +58,11 @@ def main(argv):
   parser.parse_args(argv)
 
   upstream = root()
-  message = run_git('log', '-1', '--format=%B', upstream)
-  footers = parse_footers(message)
-  git_svn_id = get_unique(footers, 'git-svn-id')
-  match = GIT_SVN_ID_PATTERN.match(git_svn_id)
-  assert match, 'No valid git-svn-id footer found on %s.' % upstream
-  print 'Found git-svn-id footer %s on %s' % (match.group(1), upstream)
-
-  parsed_svn = urlparse.urlparse(match.group(1))
+  svn_id = get_footer_svn_id(upstream)
+  assert svn_id, 'No valid git-svn-id footer found on %s.' % upstream
+  print 'Found git-svn-id footer %s on %s' % (svn_id, upstream)
+
+  parsed_svn = urlparse.urlparse(svn_id)
   path_components = parsed_svn.path.split('/')
   svn_repo = None
   svn_path = None
@@ -86,7 +83,7 @@ def main(argv):
                ' from https://chromium-access.appspot.com' % maybe_repo)
         print
       continue
-  assert svn_repo is not None, 'Unable to find svn repo for %s' % match.group(1)
+  assert svn_repo is not None, 'Unable to find svn repo for %s' % svn_id
   print 'Found upstream svn repo %s and path %s' % (svn_repo, svn_path)
 
   set_config('svn-remote.svn.url', svn_repo)

git_cl.py

@@ -44,6 +44,7 @@ import dart_format
 import fix_encoding
 import gclient_utils
 import git_common
+from git_footers import get_footer_svn_id
 import owners
 import owners_finder
 import presubmit_support
@@ -2645,13 +2646,20 @@ def IsFatalPushFailure(push_stdout):
 def CMDdcommit(parser, args):
   """Commits the current changelist via git-svn."""
   if not settings.GetIsGitSvn():
-    message = """This doesn't appear to be an SVN repository.
-If your project has a git mirror with an upstream SVN master, you probably need
-to run 'git svn init', see your project's git mirror documentation.
-If your project has a true writeable upstream repository, you probably want
-to run 'git cl land' instead.
-Choose wisely, if you get this wrong, your commit might appear to succeed but
-will instead be silently ignored."""
+    if get_footer_svn_id():
+      # If it looks like previous commits were mirrored with git-svn.
+      message = """This repository appears to be a git-svn mirror, but no
+upstream SVN master is set. You probably need to run 'git auto-svn' once."""
+    else:
+      message = """This doesn't appear to be an SVN repository.
+If your project has a true, writeable git repository, you probably want to run
+'git cl land' instead.
+If your project has a git mirror of an upstream SVN master, you probably need
+to run 'git svn init'.
+
+Using the wrong command might cause your commit to appear to succeed, and the
+review to be closed, without actually landing upstream. If you choose to
+proceed, please verify that the commit lands upstream as expected."""
     print(message)
     ask_for_data('[Press enter to dcommit or ctrl-C to quit]')
   return SendUpstream(parser, args, 'dcommit')
@@ -2660,9 +2668,10 @@ will instead be silently ignored."""
 @subcommand.usage('[upstream branch to apply against]')
 def CMDland(parser, args):
   """Commits the current changelist via git."""
-  if settings.GetIsGitSvn():
+  if settings.GetIsGitSvn() or get_footer_svn_id():
     print('This appears to be an SVN repository.')
     print('Are you sure you didn\'t mean \'git cl dcommit\'?')
+    print('(Ignore if this is the first commit after migrating from svn->git)')
     ask_for_data('[Press enter to push or ctrl-C to quit]')
   return SendUpstream(parser, args, 'land')
 

git_footers.py

@@ -48,6 +48,20 @@ def parse_footers(message):
   return footer_map
 
 
+def get_footer_svn_id(branch=None):
+  if not branch:
+    branch = git.root()
+  svn_id = None
+  message = git.run('log', '-1', '--format=%B', branch)
+  footers = parse_footers(message)
+  git_svn_id = get_unique(footers, 'git-svn-id')
+  if git_svn_id:
+    match = GIT_SVN_ID_PATTERN.match(git_svn_id)
+    if match:
+      svn_id = match.group(1)
+  return svn_id
+
+
 def get_unique(footers, key):
   key = normalize_name(key)
   values = footers[key]