bug#48740: 28.0.50; Composition text property is not always honoured

[Eli Zaretskii <eliz@gnu.org>]

> From: Ihor Radchenko <yantar92@gmail.com>
> CC: 48740@debbugs.gnu.org
> Date: Sun, 30 May 2021 21:08:52 +0800
> 
> > Step 3 above fails here:
> >
> >   $ git checkout feature/org-agenda-fontify
> >   error: pathspec 'feature/org-agenda-fontify' did not match any file(s) known to git.
> 
> Oops. Forgot to push the branch. Should work now.

It doesn't.  I'm now stuck at step 6, because there's no "item
selecting "ONGOING" state".  Perhaps because inbox.org says:

  #+SETUPFILE: /home/yantar92/Org/common.setup

?  (I also am not sure I understand what exactly item 6 wants me to
do...)

> > Anyway, would it be possible to prepare a recipe that is simpler, and
> > doesn't involve checking out and building a large package?  That'd
> > make debugging this much less unpleasant.  TIA.
> 
> Sorry, I had no luck making things simpler.

See above: I'm asking for a simpler test case because IME getting
stuff this complex to reproduce what you see on your machine is not
easy and full of frustration.  For example, you assume that the Emacs
I have installed, the one invoked by "make", is Emacs 28?  But that's
not what I have here.

> > Alternatively, show the text in the problematic buffer with all the
> > text properties, overlays, and other stuff around the problematic
> > place, and maybe that alone will suffice (but in that case it would
> > probably also be easy to generate a simpler text case...)
> 
> See the attached. I printed full string objects at steps 5, 6, and 8 for
> the whole agenda buffer, the changed agenda line, and the output of
> describe-text-properties for the first symbol in the changed
> TODO-keyword.
> 
> Hope if helps. Though text properties in agenda buffers are messy.

Ouch!  No, this doesn't help at all, sorry.  can you tell which of the
properties in the last step are in effect for the all buffer positions
of "ONGOING"?