a bug of read-passwd

[山本和彦]

Hello,

Recent changes of Emacs introduces a new bug to read-passwd.  If
read-passwd is called a filter of an asynchronous process and the
parent code executes sit-for, the cursor goes away from the minibuffer
and we cannot input our password.

The following code can reproduce this:

(defvar my-check nil)

(defun my-filter (process string)
  (set-buffer (process-buffer process))
  (read-passwd "Password: ")
  (setq my-check nil))

(let ((pro (start-process "*sh*" (current-buffer) "/bin/sh")))
  (setq my-check t)
  (set-process-filter pro 'my-filter)
  (while my-check
    (sit-for 0.1)
    (discard-input)))

The parent code calls sit-for to synchronize with its child process.
The code above is essence of a program which I use everyday.

This code works Emacs, at least, before Jun 31 2006.

--Kazu Yamamoto