bug#48406: 28.0.50; Emacs stuck in infinite loop in wait_reading_process_output when opening in fullscreen (NS)

[Andrii Kolomoiets <andreyk.mad@gmail.com>]

Alan Third <alan@idiocy.org> writes:

> On Thu, May 13, 2021 at 10:39:55PM +0200, Illia Ostapyshyn wrote:
>> When starting with
>> 
>>     (push '(fullscreen . fullboth) default-frame-alist)
>> 
>> in early-init.el, apparently Emacs get stuck in an infinite loop
>> after calling [EmacsView waitFullScreenTransition]. Please see the
>> attached backtrace. I also tried moving that command around: in
>> init.el, in emacs-startup-hook, all yield the same result.
>> 
>> Toggling fullscreen after successful startup (by not trying to start
>> in fullscreen) works ok. Also creating new frames with '(fullscreen
>> . fullboth) in default-frame-alist works well.
>> 
>> Looks like this bug was introduced by bbc48b263485c26c6823eabdbbd7e9af62178e34
>
> Hmm, I don't know what's going on. I guess it's waiting on the
> fullscreen transition before Emacs has started up fully and that's
> causing a problem?
>
> Andrii, any ideas?

I can't reproduce this.  Modifying the early-init.el file or executing
Emacs like this works fine for me:

emacs -Q --execute "(push '(fullscreen . fullboth) default-frame-alist)"

But my OS and Emacs configuration is different:
System Description:  macOS 11.2.3
Configured using: 'configure --with-ns --with-rsvg'

Illia, please check if this small fix will help:

diff --git a/src/nsterm.m b/src/nsterm.m
index bb20886ab1..ef517098bf 100644
--- a/src/nsterm.m
+++ b/src/nsterm.m
@@ -1640,8 +1640,6 @@ -(void)remove
          fullscreen also.  So skip handleFS as this will print an error.  */
       if ([view fsIsNative] && [view isFullscreen])
         {
-          // maybe it is not necessary to wait
-          [view waitFullScreenTransition];
           return;
         }