Implement partial reroll

It has been a common request to support partial series rerolls where
someone sends an amended patch as a follow-up to a previous series,
e.g.:

[PATCH v3 1/3] Patch one
[PATCH v3 2/3] Patch two
\- Re: [PATCH v3 2/3] Patch two
   Looks good, but please fix this $small_thing

   \- [PATCH v4 2/3] Patch two
[PATCH v3] Patch three

Previously, b4 refused to consider v4 as a complete new series, but now
it will properly perform a partial reroll, but only in the cases where
such patches are sent as follow-ups to the exact same patch number in
the previous series:

[PATCH v3->v4 1/3] Patch one
[PATCH     v4 2/3] Patch two
[PATCH v3->v4 3/3] Patch three

Reported-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Konstantin Ryabitsev <konstantin@linuxfoundation.org>
Link: https://lore.kernel.org/r/CAPcyv4ggbuHbqKV33_TpE7pqxvRag34baJrX3yQe-jXOikoATQ@mail.gmail.com

1 files changed, 9 insertions, 1 deletions

diff --git a/b4/mbox.py b/b4/mbox.py
index 6d4c408..f0bae35 100644
--- a/b4/mbox.py
+++ b/b4/mbox.py
@@ -47,7 +47,10 @@ def mbox_to_am(mboxfile, cmdargs, msgid):
     for key, msg in mbx.items():
         lmbx.add_message(msg)
 
-    lser = lmbx.get_series(revision=wantver, sloppytrailers=cmdargs.sloppytrailers)
+    reroll = True
+    if cmdargs.nopartialreroll:
+        reroll = False
+    lser = lmbx.get_series(revision=wantver, sloppytrailers=cmdargs.sloppytrailers, reroll=reroll)
     if lser is None and wantver is None:
         logger.critical('No patches found.')
         return
@@ -156,6 +159,11 @@ def mbox_to_am(mboxfile, cmdargs, msgid):
                 logger.info('Prepared a fake commit range for 3-way merge (%.12s..%.12s)', rstart, rend)
 
     logger.critical('---')
+    if lser.partial_reroll:
+        logger.critical('WARNING: v%s is a partial reroll from previous revisions', lser.revision)
+        logger.critical('         Please carefully review the resulting series to ensure correctness')
+        logger.critical('         Pass --no-partial-reroll to disable')
+        logger.critical('---')
     if not lser.complete and not cmdargs.cherrypick:
         logger.critical('WARNING: Thread incomplete!')