Subject: Re: bug#14531: 24.3.50; `log-view-file-prev' doesn't move to the beginning of the log buffer

From: Lars Ingebrigtsen <[email-masked]>
Date: Fri, 25 Sep 2020 13:01:43 +0200

Xue Fuqiao <[email-masked]> writes:

> In (info "(emacs) VC Change Log"):
>   `P'
>      Move to the log of the previous file, if showing logs for a
>      multi-file VC fileset.  Otherwise, just move to the beginning of
>      the log.  A numeric prefix argument is a repeat count.
>
> I tried visiting a random Emacs Lisp file (calc.el) in the bzr repo, and
> then execute `vc-print-log'.  It isn't a multi-file fileset, but
> pressing `P' does not move to the beginning of the log buffer.  Instead,
> an error message "No previous file" occurs.

I'm not sure what that command is meant to do, even after reading the
documentation and reading the code (and even reading the code doesn't
help that much, because these are easy-mmode-define-navigation
incantation).

It searches for the prev instance of:

log-view-file-re
"^\\(?:Working file: \\(?1:.+\\)\\|\\(?:SCCS/s\\.\\|Changes to \\)\\(?1:.+\\):\\)
"

in the *vc-change-log* buffer?  But ... there's nothing like that in a
git buffer?

So `P'/`N' always fails for me.  Is this just code that has bitrotted,
or is the use case just not...  explained well?

This bug was merged with:

Eduard Wiebe <[email-masked]> writes:

> it bothers me that in some situation i cannot reach the head information
> of the `vc-print-log' via `log-view-msg-prev'.
>
> I fixed the issue by following simple patch.

[...]

> -                (error "No previous %s" ,name)))
> +                (goto-char (point-min))
> +		(error "No previous %s" ,name)))

I don't understand what's meant by "the head information", but the
`n'/`p' commands in *vc-change-log* buffers seems to work well for me?

Test case:

C-x C-f calc.el
C-x v l
n
p
p

So these seem to be different bugs and the second bug has been fixed in
the intervening years?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no