bug#28864: 25.3.50; next-error-no-select does select

[Dmitry Gutov <dgutov@yandex.ru>]

Hi!

On 10/16/17 4:07 PM, Tino Calancha wrote:
> X-Debbugs-CC: Dmitry Gutov <dgutov@yandex.ru>

I'm happy to commiserate, but it's hard to tell for me which part of 
next-error* is broken for this use case. If not all of it, basically.

For instance, I don't understand why the patch at the end doesn't fix 
the problem, and makes it worse instead (the behavior becomes less 
predictable).

Why doesn't it? If we have to call next-error, and it normally changes 
window configuration, save-selected-window seems like a natural fix.

> ;; Start emacs in the emacs root source dir
> emacs -Q
> 
> M-x grep-find RET
> ;; Use following command:
> find . -type f -name ChangeLog\* -exec grep --color -nH -e baz {} +
> C-x o n ; This selects the source (shouldn't)
> ;; If doesn't select the source, try 'n' a few times more; eventually
> ;; you will be in the source.

It selects the source at the first try here, ever time.

Here's the patch that doesn't work:

diff --git a/lisp/simple.el b/lisp/simple.el
index 5ef511ce0a..16ac4b6788 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -325,8 +325,8 @@ next-error-no-select
  select the source buffer."
    (interactive "p")
    (let ((next-error-highlight next-error-highlight-no-select))
-    (next-error n))
-  (pop-to-buffer next-error-last-buffer))
+    (save-selected-window
+      (next-error n))))

  (defun previous-error-no-select (&optional n)
    "Move point to the previous error in the `next-error' buffer and 
highlight match.