bug#20134: Acknowledgement (24.4.90; Emacs slowdown to eventual hang)

[phillip.lord@newcastle.ac.uk (Phillip Lord)]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: phillip.lord@newcastle.ac.uk (Phillip Lord)
>> Cc: Eli Zaretskii <eliz@gnu.org>,  <20134@debbugs.gnu.org>
>> Date: Wed, 08 Apr 2015 16:55:27 +0100
>> 
>> I captured a backtrace from a totally hung emacs earlier, which I
>> include below. Somewhere down the line, this is actually being called by
>> my code.
>
> Any idea how come completing-read is in the call-stack:

Yep. The final hang was in the mini-buffer, right after "M-x".

I am sure that wide-column shouldn't be doing anything in the
mini-buffer, but there is not check for it.

>
>> Lisp Backtrace:
>> "modify-frame-parameters" (0xf325640)
>> "set-cursor-color" (0xf325770)
>> "cond" (0xf325928)
>> "wide-column-warning-colour" (0xf325ac8)
>> "funcall" (0xf325ac0)
>> "if" (0xf325bd8)
>> "if" (0xf325ca8)
>> "let" (0xf325e18)
>> "progn" (0xf325ef8)
>> "condition-case" (0xf326058)
>> "wide-column-post-command-hook-function" (0xf3261f0)
>> "read-from-minibuffer" (0xf326640)
>> "completing-read-default" (0xf326798)
>> "completing-read" (0xf326908)  <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
>> "byte-code" (0xf326a30)
>> "call-interactively" (0xf326c90)
>> "command-execute" (0xf326dd8)
>
> And what is wide-column-post-command-hook-function?

https://raw.githubusercontent.com/phillord/phil-emacs-packages/master/wide-column.el

It's an overly complex function which calls effectively changes the
colour of the cursor once a line gets too long. I have been suspicious
about this function for a while, but I use it in lots of buffers and it
has not changed for years (probably a decade).

Phil