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From: Elijah Newren <newren@gmail.com>
To: Phillip Wood <phillip.wood@dunelm.org.uk>
Cc: Elijah Newren via GitGitGadget <gitgitgadget@gmail.com>,
	Git Mailing List <git@vger.kernel.org>,
	Johannes Schindelin <Johannes.Schindelin@gmx.de>
Subject: Re: [PATCH] t3424: new rebase testcase documenting a stat-dirty-like failure
Date: Wed, 19 Feb 2020 08:00:45 -0800	[thread overview]
Message-ID: <CABPp-BFij++-6P2ht1EacGXaX4vA_CuBQEfz6M9w9CadXHC8Jw@mail.gmail.com> (raw)
In-Reply-To: <deae766d-f552-2e30-fb49-e7e187ee984b@gmail.com>

Hi Phillip,

On Wed, Feb 19, 2020 at 3:01 AM Phillip Wood <phillip.wood123@gmail.com> wrote:
>
> Hi Elijah
>
> On 18/02/2020 15:59, Elijah Newren wrote:
> > On Tue, Feb 18, 2020 at 7:05 AM Phillip Wood <phillip.wood123@gmail.com> wrote:
> >>
> >> Hi Elijah
> >>
> >> On 17/02/2020 19:12, Elijah Newren wrote:
> >>> I forgot to add some cc's in GitGitGadget before submitting; adding now...
> >>>
> >>> On Mon, Feb 17, 2020 at 9:15 AM Elijah Newren via GitGitGadget
> >>> <gitgitgadget@gmail.com> wrote:
> >>>>
> >>>> From: Elijah Newren <newren@gmail.com>
> >>>>
> >>>> A user discovered a case where they had a stack of 20 simple commits to
> >>>> rebase, and the rebase would succeed in picking the first commit and
> >>>> then error out with a pair of "Could not execute the todo command" and
> >>>> "Your local changes to the following files would be overwritten by
> >>>> merge" messages.
> >>>>
> >>>> Their steps actually made use of the -i flag, but I switched it over to
> >>>> -m to make it simpler to trigger the bug.  With that flag, it bisects
> >>>> back to commit 68aa495b590d (rebase: implement --merge via the
> >>>> interactive machinery, 2018-12-11), but that's misleading.  If you
> >>>> change the -m flag to --keep-empty, then the problem persists and will
> >>>> bisect back to 356ee4659bb5 (sequencer: try to commit without forking
> >>>> 'git commit', 2017-11-24)
> >>>>
> >>>> After playing with the testcase for a bit, I discovered that added
> >>>> --exec "sleep 1" to the command line makes the rebase succeed, making me
> >>>> suspect there is some kind of discard and reloading of caches that lead
> >>>> us to believe that something is stat dirty, but I didn't succeed in
> >>>> digging any further than that.
>
> I think `--exec true` would be better as it makes it clear that it's not
> a timing issue. I've changed do_recursive_merge() to print the mtime and
> mode of "DS" before and after the merge which gives
>
> HEAD is now at abd8fe3 side1
> Rebasing (1/2) # picking commit1
> DS mtime, mode before merge 1582109854, 120000
> DS mtime, mode after merge 0, 120000
> Rebasing (2/2) # picking commit2
> DS mtime, mode before merge 0, 120000
> error: Your local changes to the following files would be overwritten by
> merge:
>         DS
>
> So it looks like the problem is that when we pick commit1 we don't
> update the index entry for DS properly in merge_trees()
>
> Best Wishes
>
> Phillip

Oh, indeed, so this was my bug.  Thanks for jumping in and
investigating; I probably should have found that lead but I just
didn't.  Anyway, with your extra information I dug around for a bit
and I think I found the fix.  I'll post it soon.

  reply	other threads:[~2020-02-19 16:01 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-17 17:15 [PATCH] t3424: new rebase testcase documenting a stat-dirty-like failure Elijah Newren via GitGitGadget
2020-02-17 19:12 ` Elijah Newren
2020-02-18 15:05   ` Phillip Wood
2020-02-18 15:59     ` Elijah Newren
2020-02-19 11:01       ` Phillip Wood
2020-02-19 16:00         ` Elijah Newren [this message]
2020-02-19 16:38           ` Junio C Hamano
2020-02-19 19:33           ` Phillip Wood
2020-02-18 14:03 ` Johannes Schindelin
2020-02-18 15:55   ` Elijah Newren
2020-02-18 20:55 ` [PATCH v2] " Elijah Newren via GitGitGadget
2020-02-18 21:33   ` Junio C Hamano
2020-02-18 22:01     ` Elijah Newren
2020-02-18 22:15   ` [PATCH v3] t3433: " Elijah Newren via GitGitGadget
2020-02-19 17:04     ` [PATCH v4 0/2] " Elijah Newren via GitGitGadget
2020-02-19 17:04       ` [PATCH v4 1/2] " Elijah Newren via GitGitGadget
2020-02-19 17:04       ` [PATCH v4 2/2] merge-recursive: fix the refresh logic in update_file_flags Elijah Newren via GitGitGadget
2020-02-19 18:40         ` Junio C Hamano
2020-02-19 19:32           ` Elijah Newren
2020-02-19 21:39             ` Junio C Hamano

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