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

[Ihor Radchenko]

Eli Zaretskii <eliz@gnu.org> writes:
> That probably means the composition property is somehow invalid or
> something.

Yeah. But I fail to understand what can be wrong there. The composition
property does not appear to change. Moreover, doing the same thing but
with older pretty-symbols-mode (not the built-in prettify-symbols-mode)
does not cause any issues despite the former is also using composition.

> 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.

> 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. In theory, what org-agenda
does (after my changes) is fontifying the org buffer and copying the
fontified text with all the text properties (including composition) into
agenda view, so that fontification is preserved. I tried to repeat what
agenda does, but failed to reproduce the problem. I tried to debug the
agenda code, but, as I mentioned, composition property is not removed or
changed. I simply don't understand what is going wrong.

> 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.

Best,
Ihor

agenda-step5.txt
Description: Text document

agenda-step6.txt
Description: Text document

agenda-step8.txt
Description: Text document

agendaline-step5.txt
Description: Text document

agendaline-step6.txt
Description: Text document

agendaline-step8.txt
Description: Text document

agendasymbol-step5.txt
Description: Text document

agendasymbol-step6.txt
Description: Text document

agendasymbol-step8.txt
Description: Text document