On 11/10/20 12:08 PM, Johannes Schindelin wrote:
> Hi Jinoh,
>
> On Fri, 6 Nov 2020, Jinoh Kang wrote:
>
>> Commit 3aef54e8b8 ("diff: munmap() file contents before running external
>> diff") introduced calls to diff_free_filespec_data in
>> run_external_diff, which may pass NULL pointers.
>
> Sorry for the breakage!
No worries. Those functions were indeed confusing...
>
> Maybe the commit message could talk a bit about the circumstances when
> this happens? Of course, I (and every other reader...) could analyze your
> patch to guess what it is that triggers the bug, but it's really a good
> use of the commit message to describe it in plain English.
Agreed. The v1 PATCH, which was off-list, did explain that NULL filespecs
are used to indicate unmerged files (i.e. with unresolved conflicts).
>
>>
>> Fix this and prevent any such bugs in the future by making
>> `diff_free_filespec_data(NULL)` a no-op.
>>
>> Fixes: 3aef54e8b8 ("diff: munmap() file contents before running external diff")
>
> I am unaware of any other commit having a `Fixes:` trailer in the commit
> message. In any case, I would have expected `Fixes:` to mention a ticket
> or a bug report, not the commit that fixed _a separate_ issue (but
> unfortunately introduced this regression).
Sorry for this one; somehow I didn't notice that git and linux use
different conventions.
--
Jinoh Kang
Theori
