bug#61029: 28.2; post-command-hook error in nXML mode

[Eli Zaretskii]

> From: Vincent Lefevre <vincent@vinc17.net>
> Date: Mon, 23 Jan 2023 15:36:59 +0100
> 
> 
> Under Debian/unstable, with the emacs-gtk 1:28.2+1-10 Debian package:
> 
> Generate an XML file with the following script:
> 
> #!/bin/sh
> echo '<?xml version="1.0"?>'
> echo '<root>'
> for i in `seq 240`; do echo '<e>...</e>'; done
> echo '<e>.>.</e>'
> echo '<e><![CDATA[]]></e>'
> for i in `seq 48`; do echo '<e>...</e>'; done
> echo '<!-- -->'
> echo '</root>'
> 
> and do the following steps *exactly* under X Window
> (as Emacs must have its own window for step 3):
> 
> 1. Open the generated XML file with "emacs -Q".
> 2. Type ESC > to go to the end of the file.
> 3. Click on the space in the comment "<!-- -->".
> 4. Insert a space.
> 
> I get the following error:
> 
> Error in post-command-hook (jit-lock--antiblink-post-command): 
> (cl-assertion-failed (>= (cadr sgml--syntax-propertize-ppss) 0))

João, could you please look into this?