bug#39724: 26.3; Commit 44298ea6aa006ed227e539b02279bd3fc11fd2a6 breaks font display on macOS

[Alan Third <alan@idiocy.org>]

On Fri, Feb 21, 2020 at 01:45:08PM -0800, John Wiegley wrote:
> I noticed recently that no text was displaying in my Emacs 27 windows. As if
> everything were black and black, except that changing the font and background
> colors did not help.
> 
> It took two days of rebuilding, but I've isolated this as the breaking commit:
> 
> commit 44298ea6aa006ed227e539b02279bd3fc11fd2a6
> Author: Alan Third <alan@idiocy.org>
> Date:   Sat Feb 1 21:17:29 2020 +0000
> 
>     Use CGImage instead of NSBitmapImageRep (bug#32932)
> 
>     * src/nsterm.m (ns_update_end):
>     (ns_clear_frame): Remove forced draws.
>     (ns_draw_fringe_bitmap):
>     (ns_dumpglyphs_image): No longer need to invert images as the context
>     is already flipped.
>     ([EmacsView updateFrameSize:]):
>     ([EmacsView initFrameFromEmacs:]): Use new function.
>     ([EmacsView createDrawingBuffer]): Replaces createDrawingBufferWithRect:.
>     ([EmacsView focusOnDrawingBuffer]): Set CGImage context.
>     ([EmacsView windowDidChangeBackingProperties:]): Use new function.
>     ([EmacsView copyRect:to:]): Copy using CGImages.
>     ([EmacsView wantsUpdateLayer]):
>     ([EmacsView updateLayer]): New Functions.
>     ([EmacsView drawRect:]): We no longer do anything special here for
>     Cocoa.
>     ([EmacsView windowDidChangeBackingProperties:]): Fix indentation and
>     add NSTRACE.

Hi John, that commit isn’t in the emacs-27 branch, or if it is
something has gone terribly wrong.

> Anything prior to this works as expected. From this commit forward, all
> windows are black on black.

Zhang Haijun has reported something similar on the master branch. The
compile logs look as though there’s something wrong with his build
environment. What version of macOS are you using? Are there any errors
or warnings when you build it?
-- 
Alan Third