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

[Eli Zaretskii]

On June 4, 2020 7:01:30 AM GMT+03:00, Eli Zaretskii <eliz@gnu.org> wrote:
> On June 4, 2020 6:01:21 AM GMT+03:00, hossein valizadeh
> <valizadeh.ho@gmail.com> wrote:
> > Hello,
> > 
> > 1. This happen with every font that supports Arabic.
> > 2. When scale back to zero the problem happen again.
> > 
> > I attached my emacs-bug-info.
> > 
> > 
> > On Thu, Jun 4, 2020 at 7:09 AM hossein valizadeh
> > <valizadeh.ho@gmail.com>
> > wrote:
> > 
> > > Hello,
> > >
> > > 1. This happen with every font that supports Arabic.
> > > 2. When scale back to zero the problem happen again.
> > >
> 
> 
> Thanks.
> 
> What is your version of HarfBuzz?
> And what happens if you unset XMODIFIERS, i.e. disable the ibus input
> method framework?

Also, please go to the problematic place in the text and type "C-u C-x =", then 
post everything that Emacs shows in the *Help* buffer as result.  Please do 
this both at text scale zero, when shaping is incorrect, and at non-zero scale, 
and post the contents of *Help* in both cases.

Screenshots of both displays as well as the text of the buffer used for these 
experiments will also help, as mentioned earlier 

And finally, please try this with the version on the master branch, where a few 
fixes were installed lately.