bug#73387: 30.0.90; C-x v v in diff-mode doesn't work after C-c C-n

[Sean Whitton <spwhitton@spwhitton.name>]

Hello,

On Tue 01 Oct 2024 at 03:39am +03, Dmitry Gutov wrote:

> On 30/09/2024 16:10, Sean Whitton wrote:
>> I tested the (apply #'user-error ...) by applying your patch from
>> up-thread, though I think there may be a bug with that patch because
>> after applying it I was not able to use C-x v v to commit.
>> (FTAOD I think the attached is valid independently of your patch.)
>
> That patch was an illustration to answer the direct question (how to make
> diff-file-next work in narrowed buffer), but indeed - like mentioned in the
> same message - it didn't help on the next step.
>
> So I'm not proposing it for inclusion, your patch should very well work on its
> own.

I don't think that's quite right.

If you use C-c C-n in a diff-mode buffer with current master, then
C-x v v doesn't get far enough to call the user-error I added.
"No next file" is not the error message that you should get.

-- 
Sean Whitton