[PATCH v2 0/4] nd/unify-appending-of-s-o-b

This round cherry-pick and commit only skip S-o-b if the last one is the same while format-patch skips it if the same one appears anywhere in S-o-b list. I don't have strong opinion about which way is more correct. Though if we decide to change format-patch behavior, the series may become a bit different.

Nguyễn Thái Ngọc Duy (4):
  t4014: more tests about appending s-o-b lines
  format-patch: stricter S-o-b detection
  format-patch: update append_signoff prototype
  Unify appending signoff in format-patch, commit and sequencer

 builtin/commit.c        |  10 ++-
 builtin/log.c           |  13 +---
 log-tree.c              |  66 +++++++++++++---
 log-tree.h              |   4 +
 revision.h              |   2 +-
 sequencer.c             |  65 +---------------
 sequencer.h             |   4 -
 t/t4014-format-patch.sh | 199 ++++++++++++++++++++++++++++++++++++++++++++++++
 t/t7501-commit.sh       |   2 +-
 9 files changed, 272 insertions(+), 93 deletions(-)