bug#15155: 24.3; wrap-prefix in adaptive-wrap-prefix-mode with variable-pitch has wrong face

[Stefan Monnier <monnier@iro.umontreal.ca>]

> Then make the X window small enough so that the lines in the *scratch*
> buffer wrap. The color of the wrap-prefix (i.e. the semicolons ;;) is
> black and seems fixed width instead of red and using variable-pitch
> font.  It seems as if the wrap-prefix does not inherit the face of the
> original (comment) prefix.  This becomes more apparent when adding
> whitespaces at the beginning of the first line. Then the indentation of
> the next (wrapped) lines will also increase, however by a different
> amount because of the different font.  I suppose the wrap-prefix somehow
> uses the global default font and not the font defined by variable-pitch.
> Note that this used to work in Emacs 23 (tested with 23.4.1) where the
> wrap-prefix in the successive lines has the same face as the original
> prefix.

I have the vague impression of having already seen such a bug-report,
except the other way around (where the user complained that the
wrap-prefix was displayed in the font that happened to be active where
the line got truncated), so we "fixed" it for Emacs-24.

At least that was within the redisplay engine.  So maybe the problem we
have now is that adaptive-wrap constructs the prefix without paying
attention to existing faces.


        Stefan