GNU bug report logs -
#24206
25.1; Curly quotes generate invalid strings, leading to a segfault
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Reported by: Phil <p.stephani2 <at> gmail.com>
Date: Thu, 11 Aug 2016 18:57:02 UTC
Severity: normal
Found in version 25.1
Done: Paul Eggert <eggert <at> cs.ucla.edu>
Bug is archived. No further changes may be made.
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Message #55 received at 24206 <at> debbugs.gnu.org (full text, mbox):
Eli Zaretskii wrote:
> Its multibyteness is entirely in Emacs's imagination.
Sure, but Emacs should not substitute "\342\200\230" for "`". The point of
text-quoting-style is to substitute quotes, not byte string encodings of quotes.
>> > More generally, Fsubstitute_command_keys is quite confused about unibyte
>> > versus multibyte issues. It merges together a number of strings, and
>> > assumes that they are all multibyte iff the original string is
>> > multibyte, which is obviously not true in general.
> Could you please point out the specific places where this is done?
OK, here's a contrived example. Run this code in emacs-25:
(progn
(setq km (make-keymap))
(define-key km "≠" 'global-set-key)
(substitute-command-keys "\200\\<km>\\[global-set-key]"))
This should return a 2-character string equal to "\200≠". But in Emacs 25 it
dumps core, at least on my platform (Fedora 23 x86-64). And in Emacs 24 on my
platform it returns a malformed string that prints as "\242\1340" but has length
2. I suppose we could make Emacs 24 dump core too, though I haven't tried hard
to do that.
The problem is that the older Emacs code incorrectly assumes that the output of
substitution must be properly-encoded if the substitution changes something.
This assumption can fail if the input is unibyte and contains bytes that are not
properly-encoded for UTF-8. (There are other ways the assumption can fail.)
This bug report was last modified 8 years and 339 days ago.
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