bug#41005: problem with rendering Persian text in Emacs 27

[Pip Cet]

hossein valizadeh <valizadeh.ho@gmail.com> writes:
> I tried the patch.
> The eww problem is solved, but the problem still there, when I enable 
> auto-fill-mode or
> column-number-mode.

I only see it with column-number-mode so far (but, again, I can
reproduce it and debug further).

It's this code in indent.c

      /* Check composition sequence.  */
      if (cmp_it.id >= 0
          || (scan == cmp_it.stop_pos
              && composition_reseat_it (&cmp_it, scan, scan_byte, end,
                                        w, NEUTRAL_DIR, NULL, Qnil)))

which appears to think the sixth argument to composition_reseat_it is a
direction (it probably should be). It's actually a bidi level, and
passing NEUTRAL_DIR, which is 0, results in L2R layout being used by
hbfont_shape, as in the eww bug.

Will write a patch soon if no one beats me to it.