Emacs 27 face :extend attribute not working with pulse.el?

[Adam Porter]

Hi,

I'm still using Emacs 26.3 as my main instance, but while testing
Andrea's native-comp branch, I've also been testing Emacs 28.0.50 which,
of course, includes the changes from Emacs 27.0.90.

A while back I read on this list about the new face :extend attribute,
how it required some changes in packages like Magit, etc.  It sounded
like the issues had been resolved, that setting the :extend attribute
would restore previous behavior, etc.

However, in my Scrollkeeper package
(https://github.com/alphapapa/scrollkeeper.el), it does not seem to be
working.  One of the configurable guideline methods in the package uses
pulse-momentary-highlight-oneline to highlight a line in the buffer when
one of the scrolling commands is called (typically by setting a
background color attribute).  In Emacs 26.3, it works properly: the
entire visual line, up to the width of the window, is highlighted.  But
in Emacs 28.0.50, even when the scrollkeeper-guideline-highlight face
has the :extend attribute set to t, the highlighting does not extend to
the width of the window.

I think this issue may be in pulse.el, because evaluating this code has
the same problem:

  (pulse-momentary-highlight-one-line (point))

I hope this can be fixed before Emacs 27 is released.  Or, if I'm
missing a workaround or change that I'm supposed to apply in my code,
please let me know.

Should I file a bug report about this, or is discussion here sufficient?

Thanks,
Adam