[PATCH v4 0/6] Send help text from "git cmd -h" to stdout

Jonas Konrad noticed[*] that "git branch -h" started showing the help text to the standard error stream. It turns out that we are fairly inconsistent in our implementation of "git cmd -h". The users of parse-options API will get "If -h is the only option on the command line, give the help text to the standard output" for free, but some commands manually check for the condition and then call the usage_with_options() function, which gives the identical help text to the standard error stream. And "git branch -h" Jonas noticed was one of them.

Older commands written before parse-options API became dominant show the help text by calling the usage() function, which is meant to be used when they fail to parse their command line arguments, which has the same problem. An explicit request for help text "git cmd -h" should be fulfilled by showing the help on the standard output.

This series teachs "git $cmd -h" to send its help text to the standard output stream consistently for built-in commands.

There is a related "what status should these command exit with?" question, and an argument can be made to switch them to exit with 0, instead of historical 129, but it is left outside of the series for now.

Changes since v3:

 - The helper functions for usage_with_options() and usage() are
   renamed to show_usage_with_options_if_asked() and
   show_usage_if_asked(), respectively.

 - The call to usage() in builtin/fetch-pack.c turns out to be the
   same class as builtin/var.c that simply treats "-h" as an
   unrecognised command line option.  The fix was rewritten to
   follow the pattern taken to fix "git var -h" and moved to the
   "oddball" step.

 - The patches are reordered; the first three patches prepare the
   new helper functions and ways to test their effect, and the
   remaining patches convert the commands to use the new helper
   functions.

[Reference]

https://lore.kernel.org/git/04cfaa3b-847f-4850-9dd6-c1cf9f72807f@uni-muenster.de/

Jeff King (1):
  t0012: optionally check that "-h" output goes to stdout

Junio C Hamano (5):
  parse-options: add show_usage_with_options_if_asked()
  usage: add show_usage_if_asked()
  builtins: send usage_with_options() help text to standard output
  oddballs: send usage() help text to standard output
  builtin: send usage() help text to standard output

 builtin/am.c                |  3 +--
 builtin/branch.c            |  4 ++--
 builtin/check-ref-format.c  |  4 ++--
 builtin/checkout--worker.c  |  6 +++---
 builtin/checkout-index.c    |  6 +++---
 builtin/commit-tree.c       |  4 ++--
 builtin/commit.c            |  8 ++++----
 builtin/credential.c        |  3 ++-
 builtin/diff-files.c        |  3 +--
 builtin/diff-index.c        |  3 +--
 builtin/diff-tree.c         |  3 +--
 builtin/fast-import.c       |  3 +--
 builtin/fetch-pack.c        |  2 ++
 builtin/fsmonitor--daemon.c |  4 ++--
 builtin/gc.c                |  4 ++--
 builtin/get-tar-commit-id.c |  4 +++-
 builtin/index-pack.c        |  3 +--
 builtin/ls-files.c          |  4 ++--
 builtin/mailsplit.c         |  4 ++--
 builtin/merge-index.c       |  7 ++++++-
 builtin/merge-ours.c        |  3 +--
 builtin/merge-recursive.c   |  6 ++++++
 builtin/merge.c             |  4 ++--
 builtin/pack-redundant.c    |  3 +--
 builtin/rebase.c            |  6 +++---
 builtin/remote-ext.c        |  2 ++
 builtin/remote-fd.c         |  1 +
 builtin/rev-list.c          |  3 +--
 builtin/rev-parse.c         |  2 ++
 builtin/unpack-file.c       |  8 ++++++--
 builtin/unpack-objects.c    |  2 ++
 builtin/update-index.c      |  4 ++--
 builtin/upload-archive.c    |  6 +++---
 builtin/var.c               |  1 +
 git-compat-util.h           |  2 ++
 parse-options.c             | 10 ++++++++++
 parse-options.h             |  4 ++++
 t/helper/test-simple-ipc.c  |  4 ++--
 t/t0012-help.sh             |  3 ++-
 t/t7600-merge.sh            |  2 +-
 usage.c                     | 28 +++++++++++++++++++++++++---
 41 files changed, 122 insertions(+), 64 deletions(-)