Re: [BUG] mv: can trigger assertion failure with three parameters (builtin/mv.c:481)

From: Dragan Simic <dsimic@manjaro.org>
Date: Jan 5, 2024, 19:06 UTC
Message-ID: <7c689d58c63998e6a690207be00d3875@manjaro.org>
In-Reply-To: <xmqqil47obnw.fsf@gitster.g>

On 2024-01-05 19:52, Junio C Hamano wrote:

Show 13 quoted lines

> "Kristoffer Haugsbakk" <code@khaugsbakk.name> writes:
> 
>> You can trigger an assertion by giving these arguments to `git mv`:
>> 
>>     <dir>/file <dir> <other dir>
>> ...
>>> What did you expect to happen? (Expected behavior)
>> 
>> A normal error message if the command is nonsensical (I don’t know; 
>> that’s
>> not the point). Also `.git/index.lock` to be cleaned up.
> 
> Good find.

Yes, thanks to Kristoffer for reporting this issue.

Show 16 quoted lines

> Not just that, but when the command fails in the middle like this,
> it leaves the working tree in a half-updated state, i.e.
> 
>> ./bin-wrappers/git -C $dir mv $dir/a/a.txt $dir/a $dir/b
> 
> will first move a/a.txt to b/a.txt, then try to move a (actually,
> all contents of it, including a/a.txt) to b/a and finds that "the
> command is nonsensical" and aborts, and by that time, there is no
> a/a.txt (i.e. the working tree has been modified).  The failure
> should be made atomic, just like "git switch" to another branch may
> stop _without_ touching anything in the working tree when it may
> have to fail (e.g., due to a file being dirty).
> 
> Thanks for reporting, Kristoffer.
> 
> Any takers?

This looks like a rather interesting bugfix to me. :) Though, I've unfortunately contracted some _nasty_ flu, so I'm still simply unable to work on pretty much anything in the next 5-6 days or so, at which point I hope to be operational again.

Thus, unless someone else can get it done faster, I should be able to start working on it in about a week or so. Hopefully, that is.

Show 11 quoted lines

> $ git shortlog --since=3.years -s -n -e --no-merges v2.43.0 
> builtin/mv.c
>     15	Shaoxuan Yuan <shaoxuan.yuan02@gmail.com>
>     10	Elijah Newren <newren@gmail.com>
>      5	Ævar Arnfjörð Bjarmason <avarab@gmail.com>
>      2	Junio C Hamano <gitster@pobox.com>
>      1	Andrzej Hunt <ajrhunt@google.com>
>      1	Calvin Wan <calvinwan@google.com>
>      1	Derrick Stolee <stolee@gmail.com>
>      1	Sebastian Thiel <sebastian.thiel@icloud.com>
>      1	Torsten Bögershausen <tboegi@web.de>