[PATCH v6 00/17] hook.[ch]: new library to run hooks + simple hook conversion

A trivial update to v5 to rebase it past conflicts with topics that recently landed on "master". For v5 see: https://lore.kernel.org/git/cover-v5-00.17-00000000000-20211123T114206Z-avarab@gmail.com/

Emily Shaffer (14):
  hook: add 'run' subcommand
  gc: use hook library for pre-auto-gc hook
  am: convert {pre,post}-applypatch to use hook.h
  rebase: convert pre-rebase to use hook.h
  am: convert applypatch-msg to use hook.h
  merge: convert post-merge to use hook.h
  hooks: convert non-worktree 'post-checkout' hook to hook library
  hooks: convert worktree 'post-checkout' hook to hook library
  send-email: use 'git hook run' for 'sendemail-validate'
  git-p4: use 'git hook' to run hooks
  commit: convert {pre-commit,prepare-commit-msg} hook to hook.h
  read-cache: convert post-index-change to use hook.h
  receive-pack: convert push-to-checkout hook to hook.h
  run-command: remove old run_hook_{le,ve}() hook API

Ævar Arnfjörð Bjarmason (3):
  hook API: add a run_hooks() wrapper
  hook API: add a run_hooks_l() wrapper
  git hook run: add an --ignore-missing flag

 .gitignore                 |   1 +
 Documentation/git-hook.txt |  45 +++++++++++++
 Documentation/githooks.txt |   4 ++
 Makefile                   |   1 +
 builtin.h                  |   1 +
 builtin/am.c               |   6 +-
 builtin/checkout.c         |   3 +-
 builtin/clone.c            |   3 +-
 builtin/gc.c               |   3 +-
 builtin/hook.c             |  84 +++++++++++++++++++++++
 builtin/merge.c            |   2 +-
 builtin/rebase.c           |   3 +-
 builtin/receive-pack.c     |   7 +-
 builtin/worktree.c         |  26 +++----
 command-list.txt           |   1 +
 commit.c                   |  15 +++--
 git-p4.py                  |  70 ++-----------------
 git-send-email.perl        |  22 +++---
 git.c                      |   1 +
 hook.c                     | 131 ++++++++++++++++++++++++++++++++++++
 hook.h                     |  57 ++++++++++++++++
 read-cache.c               |   3 +-
 reset.c                    |   3 +-
 run-command.c              |  33 ---------
 run-command.h              |  17 -----
 t/t1800-hook.sh            | 134 +++++++++++++++++++++++++++++++++++++
 t/t9001-send-email.sh      |   4 +-
 27 files changed, 522 insertions(+), 158 deletions(-)
 create mode 100644 Documentation/git-hook.txt
 create mode 100644 builtin/hook.c
 create mode 100755 t/t1800-hook.sh

Range-diff against v5:
 1:  4ca52feebb8 =  1:  ba6fd47482e hook: add 'run' subcommand
 2:  6275b97a306 =  2:  cfba5c139e7 hook API: add a run_hooks() wrapper
 3:  b5b3051b2e5 =  3:  a4cca074bcb gc: use hook library for pre-auto-gc hook
 4:  c88eb5d4c25 =  4:  ce57ce1adcb am: convert {pre,post}-applypatch to use hook.h
 5:  1d8f7b7e4c1 =  5:  d6162fbef80 hook API: add a run_hooks_l() wrapper
 6:  d49a1444345 =  6:  4c1a8951fc5 rebase: convert pre-rebase to use hook.h
 7:  191fdad0165 =  7:  d8aa5e8345f am: convert applypatch-msg to use hook.h
 8:  119b92fbeae =  8:  6f8d3754b4f merge: convert post-merge to use hook.h
 9:  359ba416e84 !  9:  d3107034806 hooks: convert non-worktree 'post-checkout' hook to hook library
    @@ builtin/checkout.c
      #include "ll-merge.h"
      #include "lockfile.h"
      #include "merge-recursive.h"
    -@@ builtin/checkout.c: struct branch_info {
    +@@ builtin/checkout.c: static void branch_info_release(struct branch_info *info)
      static int post_checkout_hook(struct commit *old_commit, struct commit *new_commit,
      			      int changed)
      {
10:  b7599be95a7 ! 10:  bff7c1513ca hooks: convert worktree 'post-checkout' hook to hook library
    @@ builtin/worktree.c: static int add_worktree(const char *path, const char *refnam
     -		const char *hook = find_hook("post-checkout");
     -		if (hook) {
     -			const char *env[] = { "GIT_DIR", "GIT_WORK_TREE", NULL };
    --			cp.git_cmd = 0;
    +-			struct child_process cp = CHILD_PROCESS_INIT;
     -			cp.no_stdin = 1;
     -			cp.stdout_to_stderr = 1;
     -			cp.dir = path;
    --			cp.env = env;
    --			cp.argv = NULL;
    +-			strvec_pushv(&cp.env_array, env);
     -			cp.trace2_hook_name = "post-checkout";
     -			strvec_pushl(&cp.args, absolute_path(hook),
     -				     oid_to_hex(null_oid()),
11:  f1c84d7f627 = 11:  7d9c0a73568 git hook run: add an --ignore-missing flag
12:  4e0f94d9102 = 12:  8ea3b250dff send-email: use 'git hook run' for 'sendemail-validate'
13:  e858f332a62 = 13:  a184afd1ffd git-p4: use 'git hook' to run hooks
14:  9a5956cc028 = 14:  1a43e50617f commit: convert {pre-commit,prepare-commit-msg} hook to hook.h
15:  6fd47c4c499 = 15:  08b7e63ba5b read-cache: convert post-index-change to use hook.h
16:  b201ea46f4b = 16:  c47b36ab41a receive-pack: convert push-to-checkout hook to hook.h
17:  281d17b04db ! 17:  7b99a4b633c run-command: remove old run_hook_{le,ve}() hook API
    @@ run-command.c: int async_with_fork(void)
     -	strvec_push(&hook.args, p);
     -	while ((p = va_arg(args, const char *)))
     -		strvec_push(&hook.args, p);
    --	hook.env = env;
    +-	if (env)
    +-		strvec_pushv(&hook.env_array, (const char **)env);
     -	hook.no_stdin = 1;
     -	hook.stdout_to_stderr = 1;
     -	hook.trace2_hook_name = name;