Subject: Re: bug#26650: 26.0.50; Protect *Backtrace* from accidental killing

From: [email-masked]
Date: Tue, 25 Apr 2017 08:50:00 -0400

tags 26650 patch
quit

Tino Calancha <[email-masked]> writes:

>>
>> That's because you're still in the recursive edit, it's like evaluating
>> '(error "hi")' before hitting 'q' in the *Backtrace* buffer.  You can
>> use C-M-c (exit-recursive-edit) to get back to normal.  I think it would
>> make sense to do that automatically if you kill the *Backtrace* buffer.
> Yes, it would be useful.  I don't know how, though.
> Sometimes i kill *Bactrace* from *Ibuffer*/*Buffer List* with the
> recursive edit still ongoing.  It's a classical mistake.

Actually, the obvious way of adding `top-level' (that's what 'q' does)
to `kill-buffer-hook' does protect *Backtrace* from killing.

>From 9e2f66a300cc0c94fb1369cbf3721d41d98c2d94 Mon Sep 17 00:00:00 2001
From: Noam Postavsky <[email-masked]>
Date: Tue, 25 Apr 2017 08:39:17 -0400
Subject: [PATCH v1] Protect *Backtrace* from being killed (Bug#26650)

* lisp/emacs-lisp/debug.el (debugger-mode): Call `top-level' in
`kill-buffer-hook'.
---
 lisp/emacs-lisp/debug.el | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lisp/emacs-lisp/debug.el b/lisp/emacs-lisp/debug.el
index 94b683dcb9..0aef94f1d2 100644
--- a/lisp/emacs-lisp/debug.el
+++ b/lisp/emacs-lisp/debug.el
@@ -753,6 +753,8 @@ debugger-mode
 \\{debugger-mode-map}"
   (setq truncate-lines t)
   (set-syntax-table emacs-lisp-mode-syntax-table)
+  (add-hook 'kill-buffer-hook
+            (lambda () (if (> (recursion-depth) 0) (top-level))) nil t)
   (use-local-map debugger-mode-map))
 
 (defcustom debugger-record-buffer "*Debugger-record*"
-- 
2.11.1