git@vger.kernel.org list mirror (unofficial, one of many)
 help / color / mirror / code / Atom feed
From: Jacob Keller <jacob.keller@gmail.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: Jacob Keller <jacob.e.keller@intel.com>,
	Git mailing list <git@vger.kernel.org>, Jeff King <peff@peff.net>
Subject: Re: [RFC v2 1/1] refspec: add support for negative refspecs
Date: Thu, 24 Sep 2020 16:33:33 -0700	[thread overview]
Message-ID: <CA+P7+xr-xhC3Rr3BXT-5LLUAic1Tx27pmhZAu5T0iGwfQ6qAUA@mail.gmail.com> (raw)
In-Reply-To: <xmqqzh5onea1.fsf@gitster.c.googlers.com>

On Thu, Sep 17, 2020 at 5:02 PM Junio C Hamano <gitster@pobox.com> wrote:
>
> Jacob Keller <jacob.e.keller@intel.com> writes:
>
> > @@ -66,6 +74,28 @@ static int parse_refspec(struct refspec_item *item, const char *refspec, int fet
> >       item->src = xstrndup(lhs, llen);
> >       flags = REFNAME_ALLOW_ONELEVEL | (is_glob ? REFNAME_REFSPEC_PATTERN : 0);
> >
> > +     if (item->negative) {
> > +             struct object_id unused;
> > +
> > +             /*
> > +              * Negative refspecs only have a LHS, which indicates a ref
> > +              * (or pattern of refs) to exclude from other matches. This
> > +              * can either be a simple ref, a glob pattern, or even an
> > +              * exact sha1 match.
> > +              */
> > +             if (!*item->src)
> > +                     return 0; /* negative refspecs must not be empty */
> > +             else if (llen == the_hash_algo->hexsz && !get_oid_hex(item->src, &unused))
> > +                     item->exact_sha1 = 1; /* ok */
> > +             else if (!check_refname_format(item->src, flags))
> > +                     ; /* valid looking ref is ok */
> > +             else
> > +                     return 0;
> > +
> > +             /* other rules for negative refspecs don't apply */
>
> This comment confused me a bit; did you mean "other rules don't
> apply to negative refspecs"?
>

Yea, this should be reworded.

> > +             return 1;
> > +     }
> > +
> >       if (fetch) {
> >               struct object_id unused;
>
>
> > diff --git a/remote.c b/remote.c
> > index c5ed74f91c63..2f583d72c3f0 100644
> > --- a/remote.c
> > +++ b/remote.c
> > @@ -1058,7 +1172,7 @@ static int match_explicit(struct ref *src, struct ref *dst,
> >       const char *dst_value = rs->dst;
> >       char *dst_guess;
> >
> > -     if (rs->pattern || rs->matching)
> > +     if (rs->pattern || rs->matching || rs->negative)
> >               return 0;
>
> OK.  These "special" ones do not participate in explicit matching.
>
> > @@ -1134,6 +1248,10 @@ static char *get_ref_match(const struct refspec *rs, const struct ref *ref,
> >       int matching_refs = -1;
> >       for (i = 0; i < rs->nr; i++) {
> >               const struct refspec_item *item = &rs->items[i];
> > +
> > +             if (item->negative)
> > +                     continue;
> > +
>
> And a negative one does not decide if a ref being pushed will be
> pushed out for real at this point.  This helper is only to enumerate
> the candidate refs to be pushed out; the caller makes a separate
> call to apply_negative_refspecs() to cull the candidate list later.
>
> OK.
>
> > @@ -1339,7 +1457,7 @@ int check_push_refs(struct ref *src, struct refspec *rs)
> >       for (i = 0; i < rs->nr; i++) {
> >               struct refspec_item *item = &rs->items[i];
> >
> > -             if (item->pattern || item->matching)
> > +             if (item->pattern || item->matching || item->negative)
> >                       continue;
> >
> >               ret |= match_explicit_lhs(src, item, NULL, NULL);
>
> match_explicit_lhs(), like match_explicit(), are for explicit
> matching and should not be called for the "special" ones.  OK.
>
> > @@ -1441,6 +1559,8 @@ int match_push_refs(struct ref *src, struct ref **dst,
> >               string_list_clear(&src_ref_index, 0);
> >       }
> >
> > +     *dst = apply_negative_refspecs(*dst, rs);
> > +
> >       if (errs)
> >               return -1;
> >       return 0;
>
> And after grabbing all the candidate refs to be updated via this
> push, we filter out the ones that match negative pattern.  Can it
> also produce an error, or it can never fail (to udpate errs)?
>
> > @@ -1810,6 +1930,9 @@ int get_fetch_map(const struct ref *remote_refs,
> >  {
> >       struct ref *ref_map, **rmp;
> >
> > +     if (refspec->negative)
> > +             return 0;
> > +
>
> Again, the idea is to let the existing codepath to only deal with
> the positive refspec elements to keep the same behaviour, and let
> the caller filter the ones that match negative ones out of the
> result.  So we return without anything here for negative one.
>

Yep, that's what I went for. The only real downside here is if we
forget a code path that should honor negative refspecs and doesn't,
because it will "accept" the refspec list with such a negative
refspec, but not do anything with it.

> Nothing jumped out at me as being suspicious so far, other than that
> the GNU "?<empty>:" thing needs to be fixed as pointed out by Dscho.
>
> Thanks.

  reply	other threads:[~2020-09-24 23:33 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-21 21:52 [RFC v2 0/1] implement " Jacob Keller
2020-08-21 21:52 ` [RFC v2 1/1] refspec: add " Jacob Keller
2020-08-22 13:29   ` Johannes Schindelin
2020-08-24 15:47     ` Jacob Keller
2020-08-24 17:55     ` Junio C Hamano
2020-08-24 19:26       ` Jacob Keller
2020-09-17 20:21   ` Junio C Hamano
2020-09-18  0:01   ` Junio C Hamano
2020-09-24 23:33     ` Jacob Keller [this message]
2020-09-24 23:42     ` Jacob Keller

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

  List information: http://vger.kernel.org/majordomo-info.html

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=CA+P7+xr-xhC3Rr3BXT-5LLUAic1Tx27pmhZAu5T0iGwfQ6qAUA@mail.gmail.com \
    --to=jacob.keller@gmail.com \
    --cc=git@vger.kernel.org \
    --cc=gitster@pobox.com \
    --cc=jacob.e.keller@intel.com \
    --cc=peff@peff.net \
    --subject='Re: [RFC v2 1/1] refspec: add support for negative refspecs' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Code repositories for project(s) associated with this inbox:

	https://80x24.org/mirrors/git.git

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).