[RFC PATCH v2 0/2] MVP implementation of remote-suggested hooks

Here's an updated version of the remote-suggested hooks RFC, hopefully addressing some of the concerns people have brought up (e.g. auto-updating without letting the user verify, or prompting about hooks by default). It consists of two main parts:

 - Non-interactive prompts during certain Git commands about the
   existence of hooks. These prompts are turned *off* by default.

 - New "git hook" subcommands that can install these hooks (so that the
   aforementioned Git prompts or out-of-band installation instructions
   can tell users to install these hooks in a platform-independent way).
   These subcommands work whether or not prompts are enabled.

You can see how they work in patch 2's t1361.

In doing this, I have tried to scope down the overall effort as much as possible (to avoid security risks as much as possible, among other things), concentrating on situations that server-side hooks cannot handle. I think the main thing is that server-side hooks can check and prompt upon push, but they cannot catch problems that the client could have noticed upon commit; if the end user pushes a commit chain and only notices problems then, the user would have to redo the commits (possibly through an interactive rebase on the spot). Catching problems upon commit would prevent this problem, only necessitating amending the commit.

In the Gerrit use case, Gerrit requires a specific "Change-Id" trailer in the commit message, but I can foresee the same issue in projects that require their commit messages to fit a certain template or projects that want lints to be run but their builds, for some reason, don't run arbitrary code (or they have no builds at all).

To that end, I have added a prompt for the "commit-msg" hook if the remote has suggested one, but there are none currently installed. (Similar prompts could be added for other commit-related hooks.) The other prompts are upon clone and upon fetch (if the hooks have been updated).

Jonathan Tan (2):
  hook: move list of hooks
  hook: remote-suggested hooks

 builtin/bugreport.c               |  38 +-----
 builtin/clone.c                   |  12 ++
 builtin/fetch.c                   |  17 +++
 builtin/hook.c                    |  17 ++-
 hook.c                            | 185 +++++++++++++++++++++++++++++-
 hook.h                            |   6 +
 t/t1361-remote-suggested-hooks.sh | 105 +++++++++++++++++
 7 files changed, 340 insertions(+), 40 deletions(-)
 create mode 100755 t/t1361-remote-suggested-hooks.sh