Re: [RFC PATCH v2 0/2] configuration-based hook management

From: Jeff King <peff@peff.net>
Date: Apr 14, 2020, 20:32 UTC
Message-ID: <20200414203247.GE1879688@coredump.intra.peff.net>
In-Reply-To: <efad3927-1d8f-5545-48e9-9a58c2308273@gmail.com>

On Tue, Apr 14, 2020 at 04:15:11PM +0100, Phillip Wood wrote:

Show 25 quoted lines

> On 14/04/2020 01:54, Emily Shaffer wrote:
> > Not much to look at compared to the original RFC I sent some months ago.
> > This implements Peff's suggestion of using the "hookcmd" section as a
> > layer of indirection.
> 
> I'm not really clear what the advantage of this indirection is. It seems
> unlikely to me that different hooks will share exactly the same command line
> or other options. In the 'git secrets' example earlier in this thread each
> hook needs to use a different command line. In general a command cannot tell
> which hook it is being invoked as without a flag of some kind. (In some
> cases it can use the number of arguments if that is different for each hook
> that it handles but that is not true in general)
> 
> Without the redirection one could have
>   hook.pre-commit.linter.command = my-command
>   hook.pre-commit.check-whitespace.command = 'git diff --check --cached'
> 
> and other keys can be added for ordering etc. e.g.
>   hook.pre-commit.linter.before = check-whitespace
> 
> With the indirection one needs to set
>   hook.pre-commit.command = linter
>   hook.pre-commit.check-whitespace = 'git diff --check --cached'
>   hookcmd.linter.command = my-command
>   hookcmd.linter.pre-commit-before = check-whitespace

In the proposal I gave, you could do:

  hook.pre-commit.command = my-command
  hook.pre-commit.command = git diff --check --cached

If you want to refer to commands in ordering options (like your "before"), then you'd have to refer to their names. For "my-command" that's not too bad. For the longer one, it's a bit awkward. You _could_ do:

  hookcmd.my-command.before = git diff --check --cached

which is the same number of lines as yours. But I'd probably give it a name, like:

  hookcmd.check-whitespace.command = git diff --check --cached
  hookcmd.my-command.before = check-whitespace

That's one more line than yours, but I think it separates the concerns more clearly. And it extends naturally to more options specific to check-whitespace.

-Peff