bug#22250: 25.0.50; Eww fails to break RTL paragraph

[Eli Zaretskii <eliz@gnu.org>]

> From: Benjamin Riefenstahl <b.riefenstahl@turtle-trading.net>
> Cc: 22250@debbugs.gnu.org,  larsi@gnus.org
> Date: Tue, 29 Dec 2015 21:55:24 +0100
> 
> Benjamin Riefenstahl writes:
> >> I have uploaded this now to my private webserver as
> >> <https://odoacer.turtle-trading.net/abc-abc-abc-abc-abc-abc-abc-abc-abc-abc-abc-abc-abc-abc-test.html>.
> >> This URL reproduces the problem for me after "G RET".
> >
> Eli Zaretskii writes:
> > Not for me, it doesn't.  I tried "G RET" quite a few times, it always
> > displays correctly.
> 
> You're right it works now, since
> 
>   03dbfb9 * (eww-setup-buffer): Restore left-to-right defaults
> 
> Yesterday I had still been on the earlier f9d87dd.  Oh the joy of moving
> targets ;-)
> 
> But that's ok, so this case and my script text case are solved in
> practice.  I'm still concerned about the behaviour of vertical-motion in
> this, though.
> 
> On practical level, there is still the matter of paragraphs using
> diacritics.

Is that the only remaining problem?  Reading the rest of your message,
I'm not sure.

> Do you have an idea how to fix those?

A general idea, yes.  I need to look into the details.

> I was starting from the doc on window.hscroll in window.h and the
> docstring for window-hscroll.  The docstring says
> 
>   Return the number of columns by which WINDOW is scrolled from left
>   margin.
> 
> But with bidi-paragraph-direction set to RTL window-hscroll works with
> respect to the right margin.  I just verified again.

That's a bug in the documentation, I will fix that.  Thanks for
pointing this out.

> >> Note that at the point when vertical-motion is called and gives
> >> different answers, bidi-paragraph-direction is always right-to-left, so
> >> it looks like some window parameter that depends on
> >> bidi-paragraph-direction is cached somewhere?
> >
> > The value of bidi-paragraph-direction shouldn't matter when
> > bidi-display-reordering is nil (I've just went through the entire code
> > and didn't see any place where we use that value when
> > bidi-display-reordering is nil).  But just in case I missed something,
> > try bindings bidi-paragraph-direction to nil or left-to-right where I
> > bind bidi-display-reordering, and see if that helps.
> 
> With both variables set in shr-insert-document, I consistently get a
> seemingly correctly wrapped but left justified (LTR) paragraph,
> regardless which version I use, I tried in 5049827 (the one before
> 03dbfb9) and with the current 88e2de2.  This is with the above mentioned
> URL.

Does this mean there's one more problem?  Or does this mean my
suggestion didn't work, and is not required, as the only remaining
issue is with composed characters?

Thanks.