[0/9] git log: configurable default format for merge diffs

Message

Sergey Organov April 7, 2021, 10:55 p.m. UTC

These patches introduce capability to configure the default format of
output of diffs for merge commits by means of new log.diffMerges
configuration variable. The default format is then used by -m,
--diff-merges=m, and new --diff-merges=def options.

In particular,

  git config log.diffMerges first-parent

will change -m option format from "separate" to "first-parent" that
will in turn cause, say,

  git show -m <merge_commit>

to output diff to the first parent only, instead of appending
typically large and surprising diff to the second parent at the end of
the output.

Sergey Organov (9):
  diff-merges: introduce --diff-merges=def
  diff-merges: refactor set_diff_merges()
  diff-merges: introduce log.diffMerges config variable
  diff-merges: adapt -m to enable default diff format
  t4013: add test for --diff-merges=def
  t4013: add tests for log.diffMerges config
  t9902: fix completion tests for log.d* to match log.diffMerges
  doc/diff-options: document new --diff-merges features
  doc/config: document log.diffMerges

 Documentation/config/log.txt   |  5 +++
 Documentation/diff-options.txt | 15 ++++++---
 builtin/log.c                  |  2 ++
 diff-merges.c                  | 58 ++++++++++++++++++++++++----------
 diff-merges.h                  |  2 ++
 t/t4013-diff-various.sh        | 34 ++++++++++++++++++++
 t/t9902-completion.sh          |  3 ++
 7 files changed, 98 insertions(+), 21 deletions(-)