GNU bug report logs - #22997
25.0.50; reusing windows in pop-to-buffer while in completion-in-region-mode opens new frames

Previous Next

Full log

Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: joaotavora <at> gmail.com (João Távora)
To: bug-gnu-emacs <at> gnu.org
Subject: 25.0.50;
 reusing windows in pop-to-buffer while in completion-in-region-mode
 opens new frames
Date: Sat, 12 Mar 2016 16:32:50 +0000

Hi maintainers,

Emacs -Q and use just this customization

  (setq display-buffer-base-action
        `(display-buffer-reuse-window . ((inhibit-same-window . t))))

Do something that enters completion-in-region-mode. While in that
transient mode, invoke something that pops a buffer.

  d i s p l a  M-x complete-symbol RET
  M-x pop-to-buffer RET *Messages* RET

A new frame is created even though pop-up-frames is nil. I believe the
reason is that the *Completions* window is "soft-dedicated" in
minibuffer.el.

My fix would be to exit the transient completion-in-region-mode before
displaying other buffers. This can be done by setting
display-buffer-alist appropriately in completion-in-region-mode, much
like it sets and resets minor-mode-overriding-map-alist.

I've tried this in an extension of mine, SLY, with a mode very similar
to completion-in-region-mode, but the same technique doesn't work there
for some reason.

Anyway, the _failed_ patch after my signature.
João

diff --git a/lisp/minibuffer.el b/lisp/minibuffer.el
index 2814d02..c115476 100644
--- a/lisp/minibuffer.el
+++ b/lisp/minibuffer.el
@@ -2024,6 +2024,9 @@ completion-in-region-mode
   (setq minor-mode-overriding-map-alist
         (delq (assq 'completion-in-region-mode minor-mode-overriding-map-alist)
               minor-mode-overriding-map-alist))
+  (setq display-buffer-alist
+        (delq (assq 'completion--in-region-mode-display-guard-p display-buffer-alist)
+              display-buffer-alist))
   (if (null completion-in-region-mode)
       (progn
         (setq completion-in-region--data nil)
@@ -2035,7 +2038,11 @@ completion-in-region-mode
 	  completion-in-region-mode-predicate)
     (add-hook 'post-command-hook #'completion-in-region--postch)
     (push `(completion-in-region-mode . ,completion-in-region-mode-map)
-          minor-mode-overriding-map-alist)))
+          minor-mode-overriding-map-alist)
+    (push `(completion--in-region-mode-display-guard-p
+            (completion--in-region-mode-teardown-before-displaying-others
+             . ,display-buffer-alist))
+          display-buffer-alist)))
 
 ;; Define-minor-mode added our keymap to minor-mode-map-alist, but we want it
 ;; on minor-mode-overriding-map-alist instead.
@@ -2043,6 +2050,17 @@ completion-in-region-mode
       (delq (assq 'completion-in-region-mode minor-mode-map-alist)
             minor-mode-map-alist))
 
+;; Do some crazy `display-buffer-alist' antics to prevent the
+;; soft-dedication of *Completions* to interfere with normal
+;; display-buffer
+(defun completion--in-region-mode-display-guard-p (buffer-name _alist)
+  (not (equal "*Completions*" buffer-name)))
+
+(defun completion--in-region-mode-teardown-before-displaying-others (_buffer _action)
+  (completion-in-region-mode -1)
+  ;; explicitly return nil, for clarity
+  nil)
+
 (defvar completion-at-point-functions '(tags-completion-at-point-function)
   "Special hook to find the completion table for the thing at point.
 Each function on this hook is called in turn without any argument and should

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.