Re: [PATCH] * vc-git.el (vc-git-log-edit-mode): Font lock long summary lines.

[Protesilaos Stavrou]

> From: Sean Whitton <spwhitton@spwhitton.name>
> Date: Sun, 04 Sep 2022 10:27:09 -0700
>
> Hello,

Hello Sean,

> On Sun 04 Sep 2022 at 12:50PM +02, Lars Ingebrigtsen wrote:
>
>> Sean Whitton <spwhitton@spwhitton.name> writes:
>>
>>> I'd like to install this patch to highlight long summary lines when 
>>> composing
>>> git commit messages.  Comments welcome.
>>
>> What constitutes a too-long summary line varies by project, so I don't
>> think doing this by default would be appreciated.  But it would be a
>> user option.
>
> Ah okay, I don't recall having myself seen anything written down other
> than 50/68, though I know plenty of projects don't care about it at all.
>
> I'm thinking two defcustoms, then:
>
>     vc-git-summary-target-length defaults to nil,
>          I'll make emacs.git's .dir-locals.el set it to 50
>
>     vc-git-summary-max-length defaults to 68.
>
> (The name of the latter is based on `git-commit-summary-max-length' from
> git-commit.el on my system, which I believe is pulled in by Magit.)

Please consider defining the relevant faces as well.  The 'warning' and
'error' are not always appropriate here and by hardcoding them we no
longer have the chance to modify them easily (thinking about themes).

git-commit.el does this:

    (defface git-commit-overlong-summary
      '((t :inherit font-lock-warning-face))
      "Face used for the tail of overlong commit message summaries."
      :group 'git-commit-faces)

    (defface git-commit-nonempty-second-line
      '((t :inherit font-lock-warning-face))
      "Face used for non-whitespace on the second line of commit messages."
      :group 'git-commit-faces)

The new faces can inherit from 'warning' and 'error', of course.

All the best,
Protesilaos (or simply "Prot")

-- 
Protesilaos Stavrou
https://protesilaos.com