bug#23204: 25.1.50; Strange behaviour of ‘read-char’

[Mark Karpov]

I'm not sure if it's sort of feature (rather undocumented) or a bug.
Let's say I have a command that uses ‘read-char’ repeatedly, and it's
given a custom prompt as the first argument, like this:

  (defun my-command ()
    (interactive)
    (while (read-char "My prompt…" t)))

Now if you call this from lisp or like this: ‘M-x my-command RET’,
everything is fine: you see the prompt and you can type some chars
(press ‘C-g’ to get out of this).

But if you bind the command to key sequence, like this:

  (global-set-key (kbd "<menu> t y") #'my-command)

Then you have a nasty problem when you actually call it. Try to call it
and then type some characters — you will see no prompt and they will
accumulate in echo area indefinitely:

  menu t y h e r e SPC I SPC t y p e SPC t h i n g s SPC a n d SPC i t
  SPC i s SPC g e t t i n g SPC r a t h e r SPC l o n g

Does this work as intended? I would like to continue using ‘read-char’,
is there a way to just display my prompt in this case as well?



In GNU Emacs 25.1.50.9 (x86_64-unknown-linux-gnu, GTK+ Version 3.18.9)
 of 2016-03-24 built on arch
Repository revision: 39577d07124ee16895b9c6aab7e2c6e7d41cc715
Windowing system distributor 'The X.Org Foundation', version 11.0.11802000
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Recent messages:
Wrote /home/mark/.emacs.d/.git/COMMIT_EDITMSG
Git finished [2 times]
<menu> t y is undefined
typit-advanced-test
Quit
Would you like to play again? (y or n) n
Quit
Type "q" in help window to restore its previous buffer.
Modalka mode enabled in current buffer
Modalka mode disabled in current buffer

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