SZEDER Gábor [off-list ref] writes:

On Sun, Nov 24, 2019 at 10:44:10AM +0000, Phillip Wood wrote:

quoted

On 24/11/2019 04:49, Junio C Hamano wrote:
 ...

quoted

Hmph, that makes it sound as if the right fix is to re-read after
writing the first version of the todo file out, so that the stat
data matches reality and tells us that it has never been modified?

I think we should update the stat data after we write the todo list.

Well, yes and no.

No, because we are dealing with regression in v2.24.0 here, so the
simpler the fix the better it is for maint.  I don't think a fix can
get any simpler than my patch, with or without the suggestions from
Phillip.

Of course, the simplest "fix" for regression is to revert the
offending one, and anything else is a band-aid ;-).  The question is
which band-aid is the least risky and which one takes us the closest
to the real solution.  I tend to agree that forcing to skip checking
no matter what the variable "check_todo" says unless is_rebase_i()
qualifies as the band-aid that is the least risky.

Yes, we should definitely consider updating the stat data after the
sequencer writes the todo list, or any other options with which the
sequencer could notice a modified todo list file with less subtlety.
Alas, there is a big can of worms in that direction, see the patch
below, and we have to be very careful going that way, so I think it's
only viable in the long term, but less suitable as a regression fix
for maint.

Yes, I agree that it is much less suitable than even reverting the
offending one outright.

(Hrm, perhaps I spent too many words on the all zeroed out stat data,
and managed to sidetrack you a bit...)

No, I do not think so.  Thinking about what we need to do in the
longer term, while coming up with a shorter term fix, is a necessary
step of gaining confidence in the latter.

Again, thanks both for thinking about this issue.