From: Srinidhi Kaushik <shrinidhi.kaushik@gmail.com>
To: phillip.wood@dunelm.org.uk
Cc: git@vger.kernel.org, Johannes Schindelin <Johannes.Schindelin@gmx.de>
Subject: Re: [PATCH] push: make `--force-with-lease[=<ref>]` safer
Date: Tue, 8 Sep 2020 21:18:59 +0530 [thread overview]
Message-ID: <20200908154859.GA40807@mail.clickyotomy.dev> (raw)
In-Reply-To: <624d9e35-29b8-4012-a3d6-e9b00a9e4485@gmail.com>
Hi Phillip,
On 09/07/2020 16:23, Phillip Wood wrote:
> [...]
> Thanks for working on this, making --force-with-lease safer would be a
> valuable contribution
:)
> > The `--force-with-lease` option in `git-push`, makes sure that
> > refs on remote aren't clobbered by unexpected changes when the
> > "<expect>" ref value is explicitly specified.
>
> I think it would help to write out
> `--force-with-lease[=<refname>[:<expect>]]` so readers know what
> "<expect>" is referring to
That makes sense; noted.
> > For other cases (i.e., `--force-with-lease[=<ref>]`) where the tip
> > of the remote tracking branch is populated as the "<expect>" value,
> > there is a possibility of allowing unwanted overwrites on the remote
> > side when some tools that implicitly fetch remote-tracking refs in
> > the background are used with the repository. If a remote-tracking ref
> > was updated when a rewrite is happening locally and if those changes
> > are pushed by omitting the "<expect>" value in `--force-with-lease`,
> > any new changes from the updated tip will be lost locally and will
> > be overwritten on the remote.
> >
> > This problem can be addressed by checking the `reflog` of the branch
> > that is being pushed and verify if there in a entry with the remote
> > tracking ref. By running this check, we can ensure that refs being
> > are fetched in the background while a "lease" is being held are not
> > overlooked before a push, and any new changes can be acknowledged
> > and (if necessary) integrated locally.
> An addition safety measure would be to check the reflog of the local
> commit and the tip of the remote tracking branch dates overlap.
> Otherwise if there is an implicit fetch of a remote head that has been
> rewound we still push the local branch when we shouldn't.
This sounds much better. My initial description of the check was perhaps
a bit confusing.
> > The new check will cause `git-push` to fail if it detects the presence
> > of any updated refs that we do not have locally and reject the push
> > stating `implicit fetch` as the reason.
>
> 'implicit fetch' is a rather terse message - can we say something along
> the lines of "the remote has been updated since the last merge/push"?
I was going by the "two-word" approach like "stale info", "fetch first",
"no match", and so on. But, I'll look into wording the reject reason
along those lines.
> > An experimental configuration setting: `push.rejectImplicitFetch`
> > which defaults to `true` (when `features.experimental` is enabled)
> > has been added, to allow `git-push` to reject a push if the check
> > fails.
>
> Making this available with features.experimental initially is probably a
> good idea, I hope it will become the default if in future versions.
I hope so. :)
> > [...]
> > + case REF_STATUS_REJECT_IMPLICIT_FETCH:
> > + res = "error";
> > + msg = "implicit fetch";
> > + break;
> > +
> > case REF_STATUS_REJECT_ALREADY_EXISTS:
> > res = "error";
> > msg = "already exists";
> > diff --git a/remote.c b/remote.c
> > index c5ed74f91c..ee2dedd15b 100644
> > --- a/remote.c
> > +++ b/remote.c
> > @@ -49,6 +49,8 @@ static const char *pushremote_name;
> > static struct rewrites rewrites;
> > static struct rewrites rewrites_push;
> >
> > +static struct object_id cas_reflog_check_oid;
> > +
>
> rather than using a global variable I think it would be better just to
> pass this value around using the cb_data argument of the reflog callback
> function
I have to admit that I was hesitant to use the global variable when
writing this. For some reason I thought the callback data was used to
store results from the called function only and not pass arguments.
Will fix that in v2.
> > [...]
> > +static int oid_in_reflog_ent(struct object_id *ooid, struct object_id *noid,
> > + const char *ident, timestamp_t timestamp, int tz,
> > + const char *message, void *cb_data)
> > +{
>
> using the callback data we would have something like
>
> struct oid *remote_head = cb_data;
> return oideq(noid, remote_head);
Got it; this and the callback argument to the reflog entry function
will be updated accordingly.
> > [...]
> > +{
> > + int ret = 0;
> > + cas_reflog_check_oid = *r_oid;
> > +
> > + struct commit *r_commit, *l_commit;
>
> Our coding style is to declare all variables before any statements, so
> this should come above `cas_reflog_check_oid = *r_oid` but that line
> wants to go away anyway.
Noted; `cas_reflog_check_oid` will go away as suggested above.
> > [...]
> > + ret = (r_commit && l_commit) ? in_merge_bases(r_commit, l_commit) : 0;
> > + if (ret)
> > + goto skip;
>
> Rather than using a goto it would perhaps be better to do
>
> if (!ret)
> ret = for_each_reflog_...
>
>
OK, yes. The `goto` can be avoided here.
> > +
> > + ret = for_each_reflog_ent_reverse(local_ref_name,
> > + oid_in_reflog_ent,
> > + NULL);
>
> using the callback data we'd pass r_oid rather than NULL as the last
> argument
> > [...]
> > else if (remote_tracking(remote, ref->name, &ref->old_oid_expect))
> > oidclr(&ref->old_oid_expect);
> > - return;
> > + else
> > + do_reflog_check = 1;
> > +
> > + goto reflog_check;
>
> I'm not too keen in jumping here, can't we just check `do_reflog_check`
> below?
Yes, of course. I was trying conserve the original flow of returning
from the function right after the loop. Since this is just one condition
to check if `do_reflog_check` is set to 1; we can get rid of the `goto`
and use a `break` instead.
> [...]
Thanks for a thorough review.
--
Srinidhi Kaushik
next prev parent reply other threads:[~2020-09-08 19:44 UTC|newest]
Thread overview: 120+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-04 18:51 [PATCH] push: make `--force-with-lease[=<ref>]` safer Srinidhi Kaushik
2020-09-07 15:23 ` Phillip Wood
2020-09-08 15:48 ` Srinidhi Kaushik [this message]
2020-09-07 16:14 ` Junio C Hamano
2020-09-08 16:00 ` Srinidhi Kaushik
2020-09-08 21:00 ` Junio C Hamano
2020-09-07 19:45 ` Johannes Schindelin
2020-09-08 15:58 ` Junio C Hamano
2020-09-09 3:40 ` Johannes Schindelin
2020-09-08 16:59 ` Srinidhi Kaushik
2020-09-16 11:55 ` Johannes Schindelin
2020-09-08 19:34 ` Junio C Hamano
2020-09-09 3:44 ` Johannes Schindelin
2020-09-10 10:22 ` Johannes Schindelin
2020-09-10 14:44 ` Srinidhi Kaushik
2020-09-11 22:16 ` Johannes Schindelin
2020-09-14 11:06 ` Srinidhi Kaushik
2020-09-14 20:08 ` Junio C Hamano
2020-09-16 5:31 ` Srinidhi Kaushik
2020-09-16 10:20 ` Johannes Schindelin
2020-09-19 17:48 ` Junio C Hamano
2020-09-10 14:46 ` Junio C Hamano
2020-09-11 22:17 ` Johannes Schindelin
2020-09-14 20:07 ` Junio C Hamano
2020-09-12 15:04 ` [PATCH v2 0/2] push: make "--force-with-lease" safer Srinidhi Kaushik
2020-09-12 15:04 ` [PATCH v2 1/2] push: add "--[no-]force-if-includes" Srinidhi Kaushik
2020-09-12 18:20 ` Junio C Hamano
2020-09-12 21:25 ` Srinidhi Kaushik
2020-09-12 15:04 ` [PATCH v2 2/2] push: enable "forceIfIncludesWithLease" by default Srinidhi Kaushik
2020-09-12 18:22 ` Junio C Hamano
2020-09-12 18:15 ` [PATCH v2 0/2] push: make "--force-with-lease" safer Junio C Hamano
2020-09-12 21:03 ` Srinidhi Kaushik
2020-09-13 14:54 ` [PATCH v3 0/7] push: add "--[no-]force-if-includes" Srinidhi Kaushik
2020-09-13 14:54 ` [PATCH v3 1/7] remote: add reflog check for "force-if-includes" Srinidhi Kaushik
2020-09-14 20:17 ` Junio C Hamano
2020-09-16 10:51 ` Srinidhi Kaushik
2020-09-14 20:31 ` Junio C Hamano
2020-09-14 21:13 ` Junio C Hamano
2020-09-16 12:35 ` Johannes Schindelin
2020-09-19 17:01 ` Srinidhi Kaushik
2020-09-13 14:54 ` [PATCH v3 2/7] transport: add flag for "--[no-]force-if-includes" Srinidhi Kaushik
2020-09-13 14:54 ` [PATCH v3 3/7] send-pack: check ref status for "force-if-includes" Srinidhi Kaushik
2020-09-13 14:54 ` [PATCH v3 4/7] transport-helper: update " Srinidhi Kaushik
2020-09-13 14:54 ` [PATCH v3 5/7] builtin/push: add option "--[no-]force-if-includes" Srinidhi Kaushik
2020-09-16 12:36 ` Johannes Schindelin
2020-09-13 14:54 ` [PATCH v3 6/7] doc: add reference for "--[no-]force-if-includes" Srinidhi Kaushik
2020-09-14 21:01 ` Junio C Hamano
2020-09-16 5:35 ` Srinidhi Kaushik
2020-09-13 14:54 ` [PATCH v3 7/7] t: add tests for "force-if-includes" Srinidhi Kaushik
2020-09-16 12:47 ` [PATCH v3 0/7] push: add "--[no-]force-if-includes" Johannes Schindelin
2020-09-19 17:03 ` [PATCH v4 0/3] " Srinidhi Kaushik
2020-09-19 17:03 ` [PATCH v4 1/3] push: add reflog check for "--force-if-includes" Srinidhi Kaushik
2020-09-19 20:03 ` Junio C Hamano
2020-09-21 8:42 ` Srinidhi Kaushik
2020-09-21 18:48 ` Junio C Hamano
2020-09-23 10:22 ` Srinidhi Kaushik
2020-09-23 16:47 ` Junio C Hamano
2020-09-21 13:19 ` Phillip Wood
2020-09-21 16:12 ` Junio C Hamano
2020-09-21 18:11 ` Junio C Hamano
2020-09-23 10:27 ` Srinidhi Kaushik
2020-09-19 17:03 ` [PATCH v4 2/3] push: parse and set flag " Srinidhi Kaushik
2020-09-19 20:26 ` Junio C Hamano
2020-09-19 17:03 ` [PATCH v4 3/3] t, doc: update tests, reference " Srinidhi Kaushik
2020-09-19 20:42 ` Junio C Hamano
2020-09-23 7:30 ` [PATCH v5 0/3] push: add "--[no-]force-if-includes" Srinidhi Kaushik
2020-09-23 7:30 ` [PATCH v5 1/3] push: add reflog check for "--force-if-includes" Srinidhi Kaushik
2020-09-23 10:18 ` Phillip Wood
2020-09-23 11:26 ` Srinidhi Kaushik
2020-09-23 16:24 ` Junio C Hamano
2020-09-23 16:29 ` Junio C Hamano
2020-09-23 7:30 ` [PATCH v5 2/3] push: parse and set flag " Srinidhi Kaushik
2020-09-23 7:30 ` [PATCH v5 3/3] t, doc: update tests, reference " Srinidhi Kaushik
2020-09-23 10:24 ` Phillip Wood
2020-09-26 10:13 ` [PATCH v6 0/3] push: add "--[no-]force-if-includes" Srinidhi Kaushik
2020-09-26 10:13 ` [PATCH v6 1/3] push: add reflog check for "--force-if-includes" Srinidhi Kaushik
2020-09-26 10:13 ` [PATCH v6 2/3] push: parse and set flag " Srinidhi Kaushik
2020-09-26 10:13 ` [PATCH v6 3/3] t, doc: update tests, reference " Srinidhi Kaushik
2020-09-26 10:21 ` [PATCH v6 0/3] push: add "--[no-]force-if-includes" Srinidhi Kaushik
2020-09-26 11:46 ` [PATCH v7 " Srinidhi Kaushik
2020-09-26 11:46 ` [PATCH v7 1/3] push: add reflog check for "--force-if-includes" Srinidhi Kaushik
2020-09-26 23:42 ` Junio C Hamano
2020-09-27 12:27 ` Srinidhi Kaushik
2020-09-26 11:46 ` [PATCH v7 2/3] push: parse and set flag " Srinidhi Kaushik
2020-09-26 11:46 ` [PATCH v7 3/3] t, doc: update tests, reference " Srinidhi Kaushik
2020-09-27 14:17 ` [PATCH v8 0/3] push: add "--[no-]force-if-includes" Srinidhi Kaushik
2020-09-27 14:17 ` [PATCH v8 1/3] push: add reflog check for "--force-if-includes" Srinidhi Kaushik
2020-09-27 14:17 ` [PATCH v8 2/3] push: parse and set flag " Srinidhi Kaushik
2020-09-27 14:17 ` [PATCH v8 3/3] t, doc: update tests, reference " Srinidhi Kaushik
2020-09-30 12:54 ` Philip Oakley
2020-09-30 14:27 ` Srinidhi Kaushik
2020-09-28 17:31 ` [PATCH v8 0/3] push: add "--[no-]force-if-includes" Junio C Hamano
2020-09-28 17:46 ` SZEDER Gábor
2020-09-28 19:34 ` Srinidhi Kaushik
2020-09-28 19:51 ` Junio C Hamano
2020-09-28 20:00 ` Junio C Hamano
2020-10-01 8:21 ` [PATCH v9 " Srinidhi Kaushik
2020-10-01 8:21 ` [PATCH v9 1/3] push: add reflog check for "--force-if-includes" Srinidhi Kaushik
2020-10-02 13:52 ` Johannes Schindelin
2020-10-02 14:50 ` Johannes Schindelin
2020-10-02 16:22 ` Junio C Hamano
2020-10-02 15:07 ` Srinidhi Kaushik
2020-10-02 16:41 ` Junio C Hamano
2020-10-02 19:39 ` Srinidhi Kaushik
2020-10-02 20:14 ` Junio C Hamano
2020-10-02 20:58 ` Srinidhi Kaushik
2020-10-02 21:36 ` Junio C Hamano
2020-10-02 16:26 ` Junio C Hamano
2020-10-01 8:21 ` [PATCH v9 2/3] push: parse and set flag " Srinidhi Kaushik
2020-10-01 8:21 ` [PATCH v9 3/3] t, doc: update tests, reference " Srinidhi Kaushik
2020-10-01 15:46 ` [PATCH v9 0/3] push: add "--[no-]force-if-includes" Junio C Hamano
2020-10-01 17:12 ` Junio C Hamano
2020-10-01 17:54 ` Srinidhi Kaushik
2020-10-01 18:32 ` Junio C Hamano
2020-10-02 16:50 ` Junio C Hamano
2020-10-02 19:42 ` Srinidhi Kaushik
2020-10-03 12:10 ` [PATCH v10 " Srinidhi Kaushik
2020-10-03 12:10 ` [PATCH v10 1/3] push: add reflog check for "--force-if-includes" Srinidhi Kaushik
2020-10-03 12:10 ` [PATCH v10 2/3] push: parse and set flag " Srinidhi Kaushik
2020-10-03 12:10 ` [PATCH v10 3/3] t, doc: update tests, reference " Srinidhi Kaushik
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