bug#32038: 27.0.50; Emacs hangs when using :propertize mode line construct and not providing a property value

[Eli Zaretskii <eliz@gnu.org>]

> From: Jonathan Kyle Mitchell <kyle@jonathanmitchell.org>
> Cc: k.michal@zoho.com, 32038@debbugs.gnu.org
> Date: Wed, 04 Jul 2018 23:14:01 -0500
> 
> That makes sense. I added one function to call Fset_text_properties
> through internal_condition_case_n in the attached revised patch. The
> error gets caught and safe_eval_handler appends an error message to the
> *Messages* buffer.
> 
> The error message is put in *Messages* on the first time only though,
> subsequent (force-mode-line-update) calls just append nil. I don't know
> if that's expected for redisplay's internal messaging routines.
> 
> Thanks for reviewing the patch.

Thanks, I pushed this to the master branch, and I'm marking the bug
done.

> From 621bc3df19eaf2258c9a2ec0c72004ea8336ce0f Mon Sep 17 00:00:00 2001
> From: Jonathan Kyle Mitchell <kyle@jonathanmitchell.org>
> Date: Wed, 4 Jul 2018 22:38:29 -0500
> Subject: [PATCH] Call Fset_text_properties through internal_condition_case_n
> 
> * xdisp.c (display_mode_element, safe_set_text_properties):

The header line and the log message are sub-optimal/incomplete, and
don't mention the bug number.  Please see how I fixed that in the
actual commit, and try following this example in the future.