Subject: bug#42904: closed (Re: bug#42904: [PATCH] Non-Unicode frame title crashes Emacs on macOS)

From: [email-masked] (GNU bug Tracking System)
Date: Thu, 20 Aug 2020 17:45:03 +0000

Your bug report

#42904: [PATCH] Non-Unicode frame title crashes Emacs on macOS

which was filed against the emacs package, has been closed.

The explanation is attached below, along with your original report.
If you require more details, please reply to [email-masked].

-- 
42904: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=42904
GNU Bug Tracking System
Contact [email-masked] with problems

Subject: Re: bug#42904: [PATCH] Non-Unicode frame title crashes Emacs on macOS
From: Mattias Engdegård <[email-masked]>
To: Alan Third <[email-masked]>
Cc: [email-masked], Eli Zaretskii <[email-masked]>
Date: Thu, 20 Aug 2020 19:44:11 +0200
List-Id: <debbugs-submit.debbugs.gnu.org>

20 aug. 2020 kl. 15.24 skrev Alan Third <[email-masked]>:

> It looks good to me. The only thing I'd like you to change is to move
> the implementation down to the "Class implementations" part of
> nsfns.m.

Moved, and pushed. Thank you!

Subject: [PATCH] Non-Unicode frame title crashes Emacs on macOS
From: Mattias Engdegård <[email-masked]>
To: [email-masked]
Cc: Alan Third <[email-masked]>
Date: Mon, 17 Aug 2020 16:11:52 +0200
List-Id: <debbugs-submit.debbugs.gnu.org>

Setting a frame title that contains non-Unicode characters causes a crash in the NS backend. (Other platforms may or may not deal with it appropriately -- if you have the opportunity to test, please report.)

Since the title is typically derived from the buffer name, this is easily reproduced by

 (rename-buffer "n\351")

The crash occurs in ns_set_name_internal:

  encoded_name = ENCODE_UTF_8 (name);

Here encoded_name is still "n\351" (a 2 byte unibyte string), because the \351 couldn't be encoded.

  str = [NSString stringWithUTF8String: SSDATA (encoded_name)];

Now str is nil since "n\351" isn't valid UTF-8.

    [[view window] setTitle: str];

Here we get an NS crash because nil isn't a valid setTitle: argument.

Proposed patch attached. I didn't find any obvious way to encode an Emacs string into valid UTF-8 (with bad parts replaced) so a new function was written. The corresponding Lisp function was marked internal because it's only there for test purposes, but it could of course be promoted to non-internal if someone wants it.