Re: [PATCH v2 1/2] sequencer: extract revert message formatting into shared function

[Toon Claes <toon@iotcl.com>]

Patrick Steinhardt <ps@pks.im> writes:

> On Mon, Dec 08, 2025 at 04:30:58AM +0530, Siddharth Asthana wrote:
>> 
>> On 05/12/25 17:03, Patrick Steinhardt wrote:
>> > On Wed, Dec 03, 2025 at 01:46:10AM +0530, Siddharth Asthana wrote:
>> > > diff --git a/sequencer.c b/sequencer.c
>> > > index 5476d39ba9..9f621aef4b 100644
>> > > --- a/sequencer.c
>> > > +++ b/sequencer.c
>> > > @@ -2365,22 +2365,10 @@ static int do_pick_commit(struct repository *r,
>> > >   		if (opts->commit_use_reference) {
>> > >   			strbuf_commented_addf(&ctx->message, comment_line_str,
>> > >   				"*** SAY WHY WE ARE REVERTING ON THE TITLE LINE ***");
>> > > -		} else if (skip_prefix(msg.subject, "Revert \"", &orig_subject) &&
>> > > -			   /*
>> > > -			    * We don't touch pre-existing repeated reverts, because
>> > > -			    * theoretically these can be nested arbitrarily deeply,
>> > > -			    * thus requiring excessive complexity to deal with.
>> > > -			    */
>> > > -			   !starts_with(orig_subject, "Revert \"")) {
>> > > -			strbuf_addstr(&ctx->message, "Reapply \"");
>> > > -			strbuf_addstr(&ctx->message, orig_subject);
>> > > -			strbuf_addstr(&ctx->message, "\n");
>> > > +			strbuf_addstr(&ctx->message, "\nThis reverts commit ");
>> > >   		} else {
>> > > -			strbuf_addstr(&ctx->message, "Revert \"");
>> > > -			strbuf_addstr(&ctx->message, msg.subject);
>> > > -			strbuf_addstr(&ctx->message, "\"\n");
>> > > +			sequencer_format_revert_header(&ctx->message, msg.subject);
>> > >   		}
>> > > -		strbuf_addstr(&ctx->message, "\nThis reverts commit ");
>> > >   		refer_to_commit(opts, &ctx->message, commit);
>> > >   		if (commit->parents && commit->parents->next) {
>> > Is there any reason why we don't also handle `refer_to_commit()` in that
>> > new function?
>> 
>> 
>> The `refer_to_commit()` function depends on `struct replay_opts` and its
>> `commit_use_reference` flag, which controls whether to use abbreviated
>> commit info ("%h (%s, %ad)") or the full OID. This is specific to
>> sequencer.c's interactive workflow where users can choose the reference
>> style via --reference.
>> 
>> In replay.c, we always use the full OID via `oid_to_hex()` since it's
>> designed for non-interactive server-side operations without the
>> `replay_opts` framework.

Even if it's non-interactive, I wonder if we should make it obey the
config 'revert.reference' as well? To me it makes sense git-replay(1)
and git-revert(1) give the same outcome if that config is set.

>> Including `refer_to_commit()` would require either
>> passing `replay_opts` to the shared function (leaking sequencer internals)
>> or adding a format parameter which feels like over-engineering for current
>> needs.
>> 
>> Happy to reconsider if you think there's a cleaner way to share this.
>
> A simple alternative might be to convert the `struct replay_opts`
> parameter into a `flags` field that tells the function whether it is
> expected to use the object ID or whether it should try using the
> abbreviated commit info instead.

I was considering to add a bool for this option alone, but I agree flags
is probably more future-proof.

Patrick, I assume you don't mean to revamp the `struct replay_opts`
completely, but only the parameter that would be passed into
sequencer_format_revert_header() and refer_to_commit()?

Siddharth, I see you have plenty of good reviews on this version of the
series ([PATCH 2/2] in particular). I'd love to see you post v3. Or do
you have any open questions you need answers to before you can send it
out? Let me know if I can help with any decision-making.

-- 
Cheers,
Toon