Hi Junio,
I just realised that my use-cases wouldn't be fully covered with the
onBranch configuration option.
On Fri, May 17, 2019 at 03:25:15AM -0400, Denton Liu wrote:
> Hi Junio,
>
> On Fri, May 17, 2019 at 01:12:04PM +0900, Junio C Hamano wrote:
> > Denton Liu <liu.denton@xxxxxxxxx> writes:
> >
> > > diff --git a/Documentation/config/format.txt b/Documentation/config/format.txt
> > > index dc77941c48..d387451573 100644
> > > --- a/Documentation/config/format.txt
> > > +++ b/Documentation/config/format.txt
> > > @@ -28,14 +28,22 @@ format.headers::
> > >
> > > format.to::
> > > format.cc::
> > > +format.<branch-name>.to::
> > > +format.<branch-name>.cc::
> > > Additional recipients to include in a patch to be submitted
> > > - by mail. See the --to and --cc options in
> > > - linkgit:git-format-patch[1].
> > > + by mail. For the <branch-name> options, the recipients are only
> > > + included if patches are generated for the given <branch-name>.
> > > + See the --to and --cc options in linkgit:git-format-patch[1].
> >
> > An obvious question that somebody else may raise is:
> >
> > What makes the branch name that special? What guarantees that
> > it would stay to be the *only* thing that affects the choice of
> > these variables?
> >
> > An obvious answer to that is "nothing---we are painting ourselves in
> > a corner we cannot easily get out of with this design".
> >
> > If we want to drive format-patch differently depending on the
> > combination of the worktree location *and* the branch the patches
> > are generated from, we can do something like:
> >
> > [includeif "gitdir:/path/to/worktree/1"] path = one.inc
> > [includeif "gitdir:/path/to/worktree/2"] path = two.inc
> >
> > and then have one.inc/two.inc have customized definition of these
> > format.<branch>.{to,cc,...} variables.
> >
> > But at that point, Ævar's "wouldn't this fit better with includeif"
> > suggestion becomes more and more appropriate. Once we invent the
> > way to combine the conditions for includeIf, it would benefit not
> > just this set of variables but all others that will follow in the
> > future.
>
> Hmm, I'm starting to like Ævar's idea more the more I think about it.
>
There is one limitation with onBranch. Suppose someone runs
$ git checkout other
$ git format-patch master..feature
Then, with onBranch, they'd use get the To and Cc of `other`. But with
`format.feature.*`, format-patch correctly handles this and will use
`feature`'s To and Cc.
> >
> > Having said that, as long as we are fine with the plan to deprecate
> > and remove these three-level variables this patch introdues in the
> > future, I think it is OK to have them as a temporary stop-gap
> > measure.
With this new discovery, I'm not sure it'd be possible to deprecate it
without losing a use-case.
> >
> > > +format.<branch-name>.coverSubject::
> > > + When format-patch generates a cover letter for the given
> > > + <branch-name>, use the specified subject for the cover letter
> > > + instead of the generic template.
> >
> > I still think it is a mistake that this has to be given separately
> > and possibly redundantly from the branch description.
>
> I forgot about incorporating this. Since we don't need a branch-specific
> coverSubject anymore, we can push everything into a includeif since now
> format.<name>.coverSubject doesn't really need to exist.
>
> I'm going to repurpose --cover-subject format.coverSubject to be a
> boolean option which'll mean "process the description and if you can
> extract a subject out of it, put it on the cover letter". This way, we
> can maintain backwards compatability in case users have some specific
> use-case.
>
> Unless you'd like this processing to be the default behaviour? I'm
> impartial either way.
>
> >
> > > +static const char *branch_specific_config[] = {
> > > + "branch",
> > > + "format",
> > > + NULL
> > > +};
> >
> > Yuck. This will break a workflow where a fixed branch with a known
> > configuration is deleted and recreated over and over again
> > (e.g. think of "for-linus" branches used for request-pull in each
> > merge window).
>
> I suppose when we implement `onBranch`, you'd prefer `git branch -d` to
> also not discard those sections.
>
> >
> > > static void delete_branch_config(const char *branchname)
> > > {
> > > struct strbuf buf = STRBUF_INIT;
> > > - strbuf_addf(&buf, "branch.%s", branchname);
> > > - if (git_config_rename_section(buf.buf, NULL) < 0)
> > > - warning(_("Update of config-file failed"));
> > > + int i;
> > > + for (i = 0; branch_specific_config[i]; i++) {
> > > + strbuf_addf(&buf, "%s.%s", branch_specific_config[i], branchname);
> > > + if (git_config_rename_section(buf.buf, NULL) < 0)
> > > + warning(_("Update of config-file failed"));
> > > + strbuf_reset(&buf);
> > > + }
> >
> > This will hardcode the unwarranted limitation that the second level
> > of the format.*.var hierarchy MUST be branch names and nothing else,
> > won't it?
> >
>
> I was expecting it to only be branch names but now let's take a
> different approach.
>
> Consider patches 3-6 dropped. I'd like to queue 1-2, though, since
> they're just cleanup patches.
In light of this, I don't plan on dropping 3-6 anymore. I'm going to
reroll the new behaviour of coverSubject.
>
> Also, expect a onBranch patchset some time in the future (not the near
> future, school is busy).
>
> Thanks for your feedback, Junio.
