Re: [PATCH] git-gui: highlight comment lines in commit message

From: Johannes Sixt <j6t@kdbg.org>
Date: Mar 2, 2026, 11:30 UTC
Message-ID: <08da87b1-32c6-43c2-be1f-d60bc93ea135@kdbg.org>
In-Reply-To: <a72715e2-c3ae-4050-95e3-7fc7f9b74b5d@app.fastmail.com>

Am 01.03.26 um 22:55 schrieb Wolfgang Faust:

> These lines are stripped by wash_commit_message, but there is no indication
> in the UI that they are special and will be removed.
> Add highlighting to make it clear these lines are special.
> Signed-off-by: Wolfgang Faust <contrib-git@wolfgangfaust.com>

I like this idea! But please don't call it highlight, because we actually want to do the opposite, dim or grey out the text.

Please leave a blank line above the sign-off trailer.

> (I'm not very good with tcl, so I suspect this code could use some work.
> In particular the regex being a mangled copy of the one in the wash
> procedure seems like a code smell, though I'm not sure how to improve
> it.)

This text should go after the three-dashes, then it will be excluded from the commit message.

Show 14 quoted lines

> ---
>  git-gui/git-gui.sh | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 
> diff --git a/git-gui/git-gui.sh b/git-gui/git-gui.sh
> index d3d3aa14a9..3a0c08aa38 100755
> --- a/git-gui/git-gui.sh
> +++ b/git-gui/git-gui.sh
> @@ -3900,6 +3900,25 @@ if {[winfo exists $ui_comm]} {
> 
>      backup_commit_buffer
> 
> +    # Grey out comment lines (which are stripped from the final
> commit message by

It looks like you pasted this text into your webmail client, which destroyed the formatting of the patch. (I was able to fix this up, but...) If you have a Github account, you could use Gitgitgadget https://gitgitgadget.github.io/ for your submissions.

Show 10 quoted lines

> +    # wash_commit_message).
> +    $ui_comm tag configure commit_comment -foreground gray
> +    proc highlight_commit_comment_lines {} {
> +        global ui_comm comment_string
> +        $ui_comm tag remove commit_comment 0.0 end
> +        set text [$ui_comm get 1.0 end]
> +        # See also cmt_rx in wash_commit_message
> +        set cmt_rx [strcat {(?:^|\n)(} [regsub -all {\W}
> $comment_string {\\&}] {[^\n]*)}]
> +        set ranges [regexp -all -indices -inline -- $cmt_rx $text]

The regular expression can be simplified if we use -line matching. Then the initial (?:^|\n) can become just ^ (no parentheses), and since we do not look at the end index, the trailing [^\n]* isn't needed, either. Next, if we drop the capturing parentheses, only one pair of indexes is reported per match...

> +        for {set i 1} {$i < [llength $ranges]} {incr i 2} {

... and we can turn this into a simple foreach loop...

> +            $ui_comm tag add commit_comment \
> +                [$ui_comm index "1.0 + [lindex [lindex $ranges $i] 0] chars"] \

... with just one level of indexing here. Also, we could stash away the index computed here...

> +                [$ui_comm index "1.0 + [lindex [lindex $ranges $i] 0]
> chars lineend + 1 char"]

... and reuse it here with just the "lineend + 1char" modifier. (I wonder why we need the +1char, though.)

Show 10 quoted lines

> +        }
> +    }
> +    highlight_commit_comment_lines
> +    bind $ui_comm <<Modified>> { after idle highlight_commit_comment_lines }
> +
>      # -- If the user has aspell available we can drive it
>      #    in pipe mode to spellcheck the commit message.
>      #
> 
> base-commit: 7b2bccb0d58d4f24705bf985de1f4612e4cf06e5

-- Hannes