Re: how-to get commit content with pre-receive hook ?

From: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Date: Apr 6, 2017, 18:38 UTC
Message-ID: <CACBZZX7xA92e5n=E8fdGHiBHaqzRjP_MVWsaE2v=DcVmCO2r0w@mail.gmail.com>
In-Reply-To: <955c152a-b278-ecfd-8bc7-671c3aa81dc6@ricozome.net>

On Thu, Apr 6, 2017 at 4:03 PM, Eric Belhomme <rico-ml@ricozome.net> wrote:

Show 17 quoted lines

> Until now I ever had a quite "basic" Git usage, but now I'm working on a
> project based on Git hooks feature.. and I'm a very beginner with Git hooks
> !
>
> My need consist doing a syntax check on submitted files before a 'git push'.
> So the right hook is 'pre-receive' and I'm already able to identify the
> files I want to check using 'git show'.
>
> But I don't know how to get the *content* of the file being submitted to run
> my syntax check rules against it !
>
> I googled but most examples using pre-receive I found are doing sanity check
> on enveloppe but never on actual content of the file !
>
> Could someone here put me on the rails ?
>
> Regards,

As documented in githooks(5), the hook gets a list of these on stdin:

    <old-value> SP <new-value> SP <ref-name> LF

That means that you can use any git command to inspect that ref range, e.g.:

    git log -p <old>..<new>
    git diff <old>..<new>

Or (pseudocode):

    git show <commit>:<some path> for $(git rev-list <old>..<new>)

This is no different than how you'd inspect the content in your git repo, e.g. to get the README.md content of the master branch of git.git:

    $ git ls-tree master|grep README
    100644 blob f17af66a97c8097ab91f074478c4a5cb90425725    README.md
    $ git cat-file blob f17af66a97c8097ab91f074478c4a5cb90425725|wc
         61     397    3001