Add repo start option to create the branch based off HEAD

This makes it way easier to recover from forgetting to run repo start
before committing: just run `repo start -b new-branch`, instead of
all that tedious mucking around with reflogs.

Change-Id: I56d49dce5d027e28fbba0507ac10cd763ccfc36d
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/232712
Reviewed-by: Mike Frysinger <vapier@google.com>
Reviewed-by: David Pursehouse <dpursehouse@collab.net>
Tested-by: Mike Frysinger <vapier@google.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/subcmds/start.py b/subcmds/start.py
index 5d4c9c01..6ec0b2ce 100644
--- a/subcmds/start.py
+++ b/subcmds/start.py
@@ -40,6 +40,10 @@ revision specified in the manifest.
     p.add_option('--all',
                  dest='all', action='store_true',
                  help='begin branch in all projects')
+    p.add_option('-r', '--rev', '--revision', dest='revision',
+                 help='point branch at this revision instead of upstream')
+    p.add_option('--head', dest='revision', action='store_const', const='HEAD',
+                 help='abbreviation for --rev HEAD')
 
   def ValidateOptions(self, opt, args):
     if not args:
@@ -108,7 +112,8 @@ revision specified in the manifest.
         else:
           branch_merge = self.manifest.default.revisionExpr
 
-      if not project.StartBranch(nb, branch_merge=branch_merge):
+      if not project.StartBranch(
+          nb, branch_merge=branch_merge, revision=opt.revision):
         err.append(project)
     pm.end()