[PATCH v5 0/4] Add --base option to git-format-patch to record base tree info

Thanks for Junio's reviews and suggestions.

This version contains the following changes since v4:

 - Refine the commit log as well as the documentation according to
   Junio's comments.

 - Separate out get_base_commit function from prepare_bases to obtain
   the base commit.

 - Use repeated pair-wise computation to get the merge base for the
   validation of base commit.

 - Extract "auto handling thing" from prepare_bases and put it into
   get_base_commit.

 - Use format.useAutoBase boolean variable for the auto configuration
   in format section.

Thanks, Xiaolong.

Xiaolong Ye (4):
  patch-ids: make commit_patch_id() a public helper function
  format-patch: add '--base' option to record base tree info
  format-patch: introduce --base=auto option
  format-patch: introduce format.useAutoBase configuration

 Documentation/config.txt           |   5 ++
 Documentation/git-format-patch.txt |  60 ++++++++++++++
 builtin/log.c                      | 165 +++++++++++++++++++++++++++++++++++++
 patch-ids.c                        |   2 +-
 patch-ids.h                        |   2 +
 t/t4014-format-patch.sh            |  48 +++++++++++
 6 files changed, 281 insertions(+), 1 deletion(-)