Subject: bug#14153: 24.3.50; regression: `crm--choose-completion-string' expects wrong args

From: "Drew Adams" <[email-masked]>
Date: Sat, 6 Apr 2013 14:25:34 -0700

A regression introduced in Emacs 23.  There is no problem before 23.

`completing-read-multiple' adds `crm--choose-completion-string' to
`choose-completion-string-functions'.
 
But `crm--choose-completion-string' has the wrong signature for a
function on `choose-completion-string-functions'.
 
Each such function should accept 4 args, as follows:
 
 CHOICE - the string to insert in the buffer,
 BUFFER - the buffer in which the choice should be inserted,
 MINI-P - non-nil if BUFFER is a minibuffer, and
 BASE-SIZE - the number of characters in BUFFER before
          the string being completed.
 
But `crm--choose-completion-string' expects these args:
 
 (CHOICE  BUFFER  BASE-POSITION  &rest IGNORED)

In particular, it expects the third arg to be a position,
not a Boolean indicator of whether BUFFER is a minibuffer.
 
If the BUFFER is a minibuffer, so that MINI-P is non-nil
(e.g. `t'), then `crm--choose-completion-string'
mistakenly interprets that value as the BASE-POSITION.
 
In code that I have this leads to this kind of error:
 
Debugger entered--Lisp error: (wrong-type-argument number-or-marker-p t)
  choose-completion-string("mode-line" #<buffer  *Minibuf-1*> t)
  crm--choose-completion-string("mode-line" #<buffer  *Minibuf-1*> t nil)
  run-hook-with-args-until-success(crm--choose-completion-string "mode-line"
                                    #<buffer  *Minibuf-1*> t nil)
 
Presumably no one has run into this because their code hasn't passed t
as the value of MINI-P (?).

In GNU Emacs 24.3.50.1 (i386-mingw-nt5.1.2600)
 of 2013-04-02 on ODIEONE
Bzr revision: 112212 [email-masked]
Windowing system distributor `Microsoft Corp.', version 5.1.2600
Configured using:
 `configure --with-gcc (4.7) --no-opt --enable-checking --cflags
 -IC:/Devel/emacs/build/include --ldflags -LC:/Devel/emacs/build/lib'