bug#40919: 27.0.91; next-error-select-buffer does not always behave as documented

[Trevor Spiteri]

On 29/04/2020 22:38, Juri Linkov wrote:
>> I think the error is in the implementation.
> Then I see no way other than for next-error-select-buffer to say:
> "the current buffer was visited from next-error-last-buffer".
> Yes, this is a lie, but a white lie with good intentions, so
> next-error-find-buffer will trust this misinformation and leave
> the buffer alone.  Is this patch morally acceptable?
>
> diff --git a/lisp/simple.el b/lisp/simple.el
> index b5ba05426f..b5f148b7d5 100644
> --- a/lisp/simple.el
> +++ b/lisp/simple.el
> @@ -379,7 +379,8 @@ next-error-select-buffer
>     (list (get-buffer
>            (read-buffer "Select next-error buffer: " nil nil
>                         (lambda (b) (next-error-buffer-p (cdr b)))))))
> -  (setq next-error-last-buffer buffer))
> +  (setq next-error-last-buffer buffer)
> +  (setq next-error-buffer buffer))
>  
>  (defalias 'goto-next-locus 'next-error)
>  (defalias 'next-match 'next-error)
>
I think this would work for next-error-select-buffer. Then to fix the
other issue about new compilations, compilation-start can be modified to
use next-error-select-buffer. That way the change in compilation-start
is morally unambiguous :)

diff --git a/lisp/progmodes/compile.el b/lisp/progmodes/compile.el
index 455f181f50..41e77007c6 100644
--- a/lisp/progmodes/compile.el
+++ b/lisp/progmodes/compile.el
@@ -1910,7 +1910,7 @@ compilation-start
     (goto-char (point-max))))
 
     ;; Make it so the next C-x ` will use this buffer.
-    (setq next-error-last-buffer outbuf)))
+    (next-error-select-buffer outbuf)))
 
 (defun compilation-set-window-height (window)
   "Set the height of WINDOW according to `compilation-window-height'."