Subject: Re: [PATCH 00/11] t: reduce direct disk access to data structures

From: Patrick Steinhardt <[email-masked]>
Date: Mon, 23 Oct 2023 13:57:00 +0200

On Wed, Oct 18, 2023 at 04:40:35PM -0700, Junio C Hamano wrote:
> Patrick Steinhardt <[email-masked]> writes:
> 
> > As usual, I forgot to mention that this applies on top of current
> > master, which is at a9ecda2788 (The eighteenth batch, 2023-10-13) at the
> > time of writing. I look forward to the day where I remember to include
> > this information in the cover letter...
> 
> I heard rumors that we have a --base option that records such a
> piece of information in the format-patch output (I haven't used it
> myself).  Would it have helped, or perhaps it still needs some
> usability tweak?

I was aware of the option, but somehow never thought to use it. I guess
others are in the same boat as this is a semi-frequent topic to come up
on the mailing list.

What will fix this for me from now on is that I've now discovered the
`format.useAutoBase` config. To fix this for everybody else without
having to go through the same process we could change the default to
`format.useAutoBase=auto`. This can lead to hard-to-understand errors as
pointed out by 7efba5fa39f (format-patch: teach format.useAutoBase
"whenAble" option, 2020-10-01) though:

```
$ git format-patch -1 <an old commit>
fatal: base commit shouldn't be in revision list
```

But this was fixed via the new "whenAble" value for this configuration,
which will cause Git to ignore the case where it's unable to figure out
the base commit. So maybe we should consider to make it the new default?
I cannot think of any real downside. In the best case we simplify the
life of many maintainers of mailing list based projects. In the worst
case where we are unable to figure out the base commit nothing changes.

Patrick