[PATCH v3 0/3] format-patch: introduce option to suppress commit hashes

git format-patch is often used to create patches that are then stored in version control or displayed with diff. Having the commit hash in the "From " line usually just creates diff noise in these cases, so this series introduces --zero-commit to set that to all zeros.

Changes from v2:
* Improve the tests to be more idiomatic and avoid hard-coding line
  counts.

brian m. carlson (3):
  Introduce a null_oid constant.
  format-patch: add an option to suppress commit hash
  format-patch: check that header line has expected format

 Documentation/git-format-patch.txt |  4 ++++
 builtin/log.c                      |  5 +++++
 cache.h                            |  1 +
 log-tree.c                         |  3 ++-
 revision.h                         |  1 +
 sha1_file.c                        |  1 +
 t/t4014-format-patch.sh            | 14 ++++++++++++++
 7 files changed, 28 insertions(+), 1 deletion(-)