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From: Christian Couder <christian.couder@gmail.com>
To: Derrick Stolee <stolee@gmail.com>
Cc: git <git@vger.kernel.org>, "Junio C Hamano" <gitster@pobox.com>,
	"Jeff King" <peff@peff.net>,
	"Ben Peart" <Ben.Peart@microsoft.com>,
	"Jonathan Tan" <jonathantanmy@google.com>,
	"Jonathan Nieder" <jrnieder@gmail.com>,
	"Nguyen Thai Ngoc Duy" <pclouds@gmail.com>,
	"Mike Hommey" <mh@glandium.org>,
	"Lars Schneider" <larsxschneider@gmail.com>,
	"Eric Wong" <e@80x24.org>,
	"Christian Couder" <chriscool@tuxfamily.org>,
	"Jeff Hostetler" <jeffhost@microsoft.com>,
	"Eric Sunshine" <sunshine@sunshineco.com>,
	"Beat Bolli" <dev+git@drbeat.li>,
	"SZEDER Gábor" <szeder.dev@gmail.com>,
	"Ramsay Jones" <ramsay@ramsayjones.plus.com>
Subject: Re: [PATCH v5 04/16] promisor-remote: implement promisor_remote_get_direct()
Date: Tue, 25 Jun 2019 15:50:21 +0200	[thread overview]
Message-ID: <CAP8UFD2-BUVsaVcO-pRNY+qc8WBZC=NUOQHnNYbBVKc=q_aOSg@mail.gmail.com> (raw)
In-Reply-To: <CAP8UFD0zvqC2s3_RsWfKwoWQL=2iV6PbaL8+hwUXrWBVe+6sgA@mail.gmail.com>

On Fri, May 31, 2019 at 7:10 AM Christian Couder
<christian.couder@gmail.com> wrote:

> On Thu, May 30, 2019 at 7:21 PM Derrick Stolee <stolee@gmail.com> wrote:
> >
> > On 4/9/2019 12:11 PM, Christian Couder wrote:

> > > +{
> > > +     int i, missing_nr = 0;
> > > +     int *missing = xcalloc(oid_nr, sizeof(*missing));
> > > +     struct object_id *old_oids = *oids;
> > > +     struct object_id *new_oids;
> > > +     int old_fetch_if_missing = fetch_if_missing;
> > > +
> > > +     fetch_if_missing = 0;
> >
> > This global 'fetch_if_missing' swap seems very fragile. I'm guessing you are using
> > it to prevent a loop when calling oid_object_info_extended() below. Can you instead
> > pass a flag to the method that disables the fetch_if_missing behavior?
>
> If such a flag existed when I wrote the function I would certainly
> have used it, as I also dislike this kind of messing with a global
> (and globals in general).
>
> I will see if I can do something about it according to what you
> suggest later in this thread.

In the V6 patch series I just sent, the new
OBJECT_INFO_SKIP_FETCH_OBJECT flag that you introduced is used.

> > > +     for (i = 0; i < oid_nr; i++)
> > > +             if (oid_object_info_extended(the_repository, &old_oids[i], NULL, 0)) {
> >
> > A use of "the_repository" this deep in new code is asking for a refactor later to remove it.
> > Please try to pass a "struct repository *r" through your methods so we minimize references
> > to the_repository (and the amount of work required to remove them later).
>
> Ok, I will take a look at that.

A "struct repository *r" is passed in V6. I forgot to mention that in
the cover letter.

> > > +                     missing_nr = remove_fetched_oids(&missing_oids, missing_nr, to_free);
> >
> > Here is the one call, and after this assignment "missing_nr" does mean the number of missing objects.
> > However, I do think this could be clarified by using remaining_nr and remaining_oids.
>
> Ok, I will take a look at using "remaining_nr" and "remaining_oids".

Done in V6 too.

> > > +                     if (missing_nr) {
> > > +                             to_free = 1;
> > > +                             continue;
> > > +                     }
> >
> > Now this block took a bit to grok. You use to_free in the if(to_free) free(missing_oids); below.
> > But it also changes the behavior of remove_fetched_oids(). This means that the first time
> > remove_fetched_oids() will preserve the list (because it is the input list) but all later
> > calls will free the newly-created intermediate list. This checks out.
> >
> > What is confusing to me: is there any reason that missing_nr would be zero in this situation?
>
> I don't think so but I will check again, and maybe add a comment.

Actually missing_nr, or now remaining_nr, would be 0 if all the
promised objects have been fetched.

> > > +             }
> > > +             res = 0;
> > > +             break;
> > > +     }
> > > +
> > > +     if (to_free)
> > > +             free(missing_oids);
> > > +
> > > +     return res;
> > > +}
> >
> > While the test coverage report brought this patch to my attention, it does seem correct.
> > I still think a test exposing this method would be good, especially one that requires
> > a fetch_objects() call to multiple remotes to really exercise the details of remove_fetched_oids().
>
> Yeah, I would like to actually test it. I will take another look at
> what can be done to test this. Perhaps I will look at what can be done
> to still get some objects when fetching from a promisor/partial clone
> remote even when it doesn't have all of the objects we request.

I haven't improved test coverage or looked at how we could better
handle a partial fetch. I plan to look at that soon.

Thanks,
Christian.

  reply	other threads:[~2019-06-25 13:50 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-09 16:11 [PATCH v5 00/16] Many promisor remotes Christian Couder
2019-04-09 16:11 ` [PATCH v5 01/16] t0410: remove pipes after git commands Christian Couder
2019-04-09 16:11 ` [PATCH v5 02/16] fetch-object: make functions return an error code Christian Couder
2019-04-09 16:11 ` [PATCH v5 03/16] Add initial support for many promisor remotes Christian Couder
2019-04-09 16:11 ` [PATCH v5 04/16] promisor-remote: implement promisor_remote_get_direct() Christian Couder
2019-05-30 17:21   ` Derrick Stolee
2019-05-30 20:46     ` Johannes Schindelin
2019-05-30 20:54       ` Derrick Stolee
2019-05-31 11:35         ` Johannes Schindelin
2019-05-31 16:14         ` Junio C Hamano
2019-05-31  5:10     ` Christian Couder
2019-06-25 13:50       ` Christian Couder [this message]
2019-04-09 16:11 ` [PATCH v5 05/16] promisor-remote: add promisor_remote_reinit() Christian Couder
2019-04-09 16:11 ` [PATCH v5 06/16] promisor-remote: use repository_format_partial_clone Christian Couder
2019-04-09 16:11 ` [PATCH v5 07/16] Use promisor_remote_get_direct() and has_promisor_remote() Christian Couder
2019-04-09 16:11 ` [PATCH v5 08/16] diff: use promisor-remote.h instead of fetch-object.h Christian Couder
2019-04-09 16:11 ` [PATCH v5 09/16] promisor-remote: parse remote.*.partialclonefilter Christian Couder
2019-04-09 16:11 ` [PATCH v5 10/16] builtin/fetch: remove unique promisor remote limitation Christian Couder
2019-04-09 16:11 ` [PATCH v5 11/16] t0410: test fetching from many promisor remotes Christian Couder
2019-04-09 16:11 ` [PATCH v5 12/16] partial-clone: add multiple remotes in the doc Christian Couder
2019-04-09 16:11 ` [PATCH v5 13/16] remote: add promisor and partial clone config to " Christian Couder
2019-04-09 16:11 ` [PATCH v5 14/16] Remove fetch-object.{c,h} in favor of promisor-remote.{c,h} Christian Couder
2019-04-09 16:11 ` [PATCH v5 15/16] Move repository_format_partial_clone to promisor-remote.c Christian Couder
2019-04-09 16:11 ` [PATCH v5 16/16] Move core_partial_clone_filter_default " Christian Couder
2019-04-15  9:27 ` [PATCH v5 00/16] Many promisor remotes Junio C Hamano
2019-04-15 10:30   ` Junio C Hamano
2019-04-15 10:39     ` Christian Couder
2019-04-15 10:37   ` Christian Couder

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