From: Phillip Wood <phillip.wood123@gmail.com>
Date: Thu, 26 May 2022 11:17:33 GMT
Subject: Re: [PATCH] revert: optionally refer to commit in the "reference" format
Message-ID: <4c8ea23d-1a1d-efd4-6c11-7c08f8728d59@gmail.com>
In-Reply-To: <xmqqsfp2b30k.fsf@gitster.g>

Hi Junio

On 22/05/2022 05:32, Junio C Hamano wrote:
> A typical "git revert" commit uses the full title of the original
> commit in its title, and starts its body of the message with:
> 
>      This reverts commit 8fa7f667cf61386257c00d6e954855cc3215ae91.
> 
> This does not encourage the best practice of describing not just
> "what" (i.e. "Revert X" on the title says what we did) but "why"
> (i.e. and it does not say why X was undesirable).
> 
> We can instead phrase this first line of the body to be more like
> 
>      This reverts commit 8fa7f667 (do this and that, 2022-04-25)
> 
> so that the title does not have to be
> 
>      Revert "do this and that"
> 
> We can instead use the title to describe "why" we are reverting the
> original commit.
> 
> Introduce the "--reference" option to "git revert", and also the
> revert.reference configuration variable, which defaults to false, to
> tweak the title and the first line of the draft commit message for
> when creating a "revert" commit.

I think this is a good idea which will hopefully improve project histories.

> diff --git a/builtin/revert.c b/builtin/revert.c
> index 51776abea6..ada51e46b9 100644
> --- a/builtin/revert.c
> +++ b/builtin/revert.c
> @@ -116,6 +116,8 @@ static int run_sequencer(int argc, const char **argv, struct replay_opts *opts)
>   			N_("option for merge strategy"), option_parse_x),
>   		{ OPTION_STRING, 'S', "gpg-sign", &opts->gpg_sign, N_("key-id"),
>   		  N_("GPG sign commit"), PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
> +		OPT_BOOL(0, "reference", &opts->commit_use_reference,
> +			 N_("use the 'reference' format to refer to commits")),

This option is being added to base_options which applies to cherry-pick 
as well as revert. There is a "if" statement just below this hunk which 
adds cherry-pick specific options, I think we want to add this new 
option in an else block added to that "if" statement.

>   static int do_pick_commit(struct repository *r,
>   			  struct todo_item *item,
>   			  struct replay_opts *opts,
> @@ -2167,14 +2184,19 @@ static int do_pick_commit(struct repository *r,
>   		base_label = msg.label;
>   		next = parent;
>   		next_label = msg.parent_label;
> -		strbuf_addstr(&msgbuf, "Revert \"");
> -		strbuf_addstr(&msgbuf, msg.subject);
> -		strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
> -		strbuf_addstr(&msgbuf, oid_to_hex(&commit->object.oid));
> +		if (!opts->commit_use_reference) {
> +			strbuf_addstr(&msgbuf, "Revert \"");
> +			strbuf_addstr(&msgbuf, msg.subject);
> +			strbuf_addstr(&msgbuf, "\"");
> +		} else {
> +			strbuf_addstr(&msgbuf, "DESCRIBE WHY WE ARE REVERTING HERE");

In format-patch we add three asterisks to the beginning and end of the 
dummy subject and body lines to encourage the user to edit them - is 
that worth doing here as well?

Best Wishes

Phillip