Subject: bug#11983: 24.1; Electric-command-loop broken?

From: "Roland Winkler" <[email-masked]>
Date: Wed, 18 Jul 2012 15:54:45 -0500

I am trying to understand Electric-command-loop in electric.el
(this is used by BBDB 3):

Two things:

- The code contains a hard-coded

    (setq universal-argument-num-events 0)

  Apparently this is never reset, so exiting Electric-command-loop
  leaves behind this binding.

- The doc string says

  ;; Given third argument non-nil, it
  ;; INHIBITS quitting unless the user types C-g at toplevel.  This is
  ;; so user can do things like C-u C-g and not get thrown out.

  Yet it appears to me, that even for C-u C-g the user gets thrown out.
  Here is a slightly simplified version of the code from Electric-command-loop
  It does not distinguish between C-g and C-u C-g.
  Unfortunately, this hackery goes beyond my understanding of Emacs
  internals.

(catch 'return-tag
  (let (cmd (inhibit-quit t))
    (while t
      (setq cmd (read-key-sequence "Prompt: "))
      (setq last-command-event (aref cmd (1- (length cmd)))
            this-command (key-binding cmd t)
            cmd this-command)
      ;; This makes universal-argument-other-key work.
      (setq universal-argument-num-events 0)
      (if (or (prog1 quit-flag (setq quit-flag nil))
              (eq last-input-event ?\C-g))
          (progn (setq unread-command-events nil
                       prefix-arg nil)
                 ;; If it wasn't canceling a prefix character, then quit.
                 (if (or (= (length (this-command-keys)) 1)
                         (not inhibit-quit)) ; safety
                     (throw 'return-tag (this-command-keys))
                   (setq cmd nil))))
      (setq current-prefix-arg prefix-arg)
      (condition-case nil
          (progn (command-execute cmd)
                 (setq last-command this-command))
        (error nil)))))

In GNU Emacs 24.1.1 (x86_64-unknown-linux-gnu, GTK+ Version 2.20.1)
 of 2012-06-10 on regnitz
Windowing system distributor `The X.Org Foundation', version 11.0.10706000