[PATCH 0/6] configuration-based hook management

An implementation of the first piece of the proposal given in lore.kernel.org/git/20191116011125.GG22855@google.com.

Teaches a new command, 'git hook', which will someday include 'git hook --add ...', 'git hook --edit ...', and maybe more. For now, just teach it how to check the config files with 'git hook --list ...'.

The hooks-to-run list is collected in a new library, hook.o, which can someday reimplement find_hook() or otherwise be invoked to run all hooks for a given hookname (e.g. "pre-commit").

The change to config.[ch] allows us to display a similar scope name to the one a user may use to 'git config --add' or later 'git hook --add' a hook at a certain scope, e.g.:

  $ git hook --list pre-commit
  001	global	~/foo.sh
  $ git hook --add --global pre-commit 005 ~/bar.sh
  Added.
  001	global	~/foo.sh
  005	global	~/bar.sh

There are config examples in many of the commit messages in this chain.

Before I consider "--list" to be done, I also want to add support to check "hook.runHookDir" and take .git/hooks/* into account. But I wanted us to spend time chewing on the config format for a while before I got too far.

It's also very possible (likely, even!) to put this feature behind an experimental flag, which gives us more room to change the config format if we want before the feature is "done".

In the discussion thread with brian, I also mentioned a self-paced deprecation of hooks which live in .git/hooks/, which I'm aware some users may not want to follow. However, it occurred to me that we may be able to hide a Git-paced deprecation behind a config macro (since those are new and shiny) which is opt-in, and handles something like:

  hook.runHookDir = true
  hook.warnHookDir = false

  {some months pass, we are sure config-based hooks are working nicely}

  hook.runHookDir = true
  hook.warnHookDir = true

  {so start yelling at users to move away, and wait some more
  months/years}

  hook.runHookDir = false

  {users who have opted into the hookdir phaseout macro are no longer
  using the hookdir}

As it's opt-in (and easily reversible by changing configs) this might be a good middle ground for the "deprecate or not" discussion brian and I had.

Thanks.
 - Emily

Emily Shaffer (6):
  hook: scaffolding for git-hook subcommand
  config: add string mapping for enum config_scope
  hook: add --list mode
  hook: support reordering of hook list
  hook: remove prior hook with '---'
  hook: teach --porcelain mode

 .gitignore                    |  1 +
 Documentation/git-hook.txt    | 53 ++++++++++++++++++++
 Makefile                      |  2 +
 builtin.h                     |  1 +
 builtin/hook.c                | 80 ++++++++++++++++++++++++++++++
 config.c                      | 17 +++++++
 config.h                      |  1 +
 git.c                         |  1 +
 hook.c                        | 93 +++++++++++++++++++++++++++++++++++
 hook.h                        | 14 ++++++
 t/t1360-config-based-hooks.sh | 89 +++++++++++++++++++++++++++++++++
 11 files changed, 352 insertions(+)
 create mode 100644 Documentation/git-hook.txt
 create mode 100644 builtin/hook.c
 create mode 100644 hook.c
 create mode 100644 hook.h
 create mode 100755 t/t1360-config-based-hooks.sh