Re: [PATCH] git-gui: do not end the commit message with an empty line

From: Junio C Hamano <gitster@pobox.com>
Date: May 14, 2025, 21:14 UTC
Message-ID: <xmqqv7q27v49.fsf@gitster.g>
In-Reply-To: <ed1ca9fa-15f0-4601-be31-8a578c7fb788@kdbg.org>

Johannes Sixt <j6t@kdbg.org> writes:

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> The commit message is processed to remove unnecessary empty lines.
> In particular, it is ensured that the text ends with at most one LF
> character. This one is always present, because the Tk text widget
> ensures that is present.
>
> However, we forgot that the processed text is written to the commit
> message file using 'puts', which also appends a LF character, so that
> the final commit message ends with two LF. Trim all trailing LF
> characters, and while we are here, use `string trim`, which lets us
> remove the leading LF in the same command.

The above reasoning look sensible.

As git-gui uses plumbing commit-tree to create the commit object, it has to be more careful not to have extra blank lines, as it cannot assume stripspace internal to "git commit"?

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>
> Reported-by: Gareth Fenn <garethfenn@gmail.com>
> Signed-off-by: Johannes Sixt <j6t@kdbg.org>
> ---
>  lib/commit.tcl | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)

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> diff --git a/lib/commit.tcl b/lib/commit.tcl
> index a570f9cdc6a4..f3c714e600ac 100644
> --- a/lib/commit.tcl
> +++ b/lib/commit.tcl
> @@ -214,12 +214,10 @@ You must stage at least 1 file before you can commit.
>  	global comment_string
>  	set cmt_rx [strcat {(^|\n)} [regsub -all {\W} $comment_string {\\&}] {[^\n]*}]
>  	regsub -all $cmt_rx $msg {\1} msg
> -	# Strip leading empty lines
> -	regsub {^\n*} $msg {} msg
> +	# Strip leading and trailing empty lines
> +	set msg [string trim $msg \n]
>  	# Compress consecutive empty lines
>  	regsub -all {\n{3,}} $msg "\n\n" msg
> -	# Strip trailing empty line
> -	regsub {\n\n$} $msg "\n" msg
>  	if {$msg eq {}} {
>  		error_popup [mc "Please supply a commit message.