bug#64596: 30.0.50; On FIXME: in src/buffer.c:1481 (force-mode-line-update)

[Ihor Radchenko]

Eli Zaretskii <eliz@gnu.org> writes:

> What we do need is to make some better order out of these flags,
> understand better what does each one of them tell the display engine,
> and perhaps make some of them more selective.  And we need to document
> these understandings.

I agree.
>From my recent reading of the commentary in xdisp.c, one apparently
missing summary is which window and frame components are considered by
the redisplay code.

"Glyph rows." section in the top comment talk about margins + text area,
but the real redisplay_internal appears to consider (1) title bars; (2)
menu bars; (3) header line; (4) tab line; (5) mode-line; (6) window
text; (7) echo area (which is treated specially).

> ....  But I will not agree to
> random poking at this or that particular flag, unless there's
> convincing evidence that it causes a display bug or a significant
> performance problem.  Because otherwise making changes in code that we
> don't sufficiently understand can only cause bugs, and guess who gets
> to work on fixing them.

That's understandable.
But the general idea of having some kind of "experimental" flag might be
still useful in other situations. Not necessarily redisplay.
Of course, such experiments should be still weighed carefully.

-- 
Ihor Radchenko // yantar92,
Org mode contributor,
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