bug#70367: 30.0.50; Inconsistent Syntax Highlighting

[Eli Zaretskii <eliz@gnu.org>]

> Cc: 70367@debbugs.gnu.org
> Date: Sat, 13 Apr 2024 20:44:37 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> 
> > From: Amol Surati <suratiamol@gmail.com>
> > Date: Sat, 13 Apr 2024 18:12:54 +0530
> > 
> > The problem is not found in terminal emacs built from the released 29.3.tar.gz,
> > or with emacs running under GUI (i.e. under PGTK).
> > 
> > The problem is seen with terminal emacs built from the master branch, at various
> > commit levels.
> > 
> > Problem: When a large file (for e.g. vulkan_core.h) is opened, certain
> > constructs have their syntax highlighting broken. The video found at [1] shows
> > the behaviour. At the end of the video, one can see one instance of the problem;
> > the syntax highlighting for the enum constant
> > 'VK_STRUCTURE_TYPE_EVENT_CREATE_INFO = 10,' abruptly breaks. The entire
> > identifier VK_STRUCTURE_TYPE_EVENT_CREATE_INFO must be one colour. Instead,
> > 'VK_STRUCTURE_TYPE_EVENT_CREA' is of the expected colour, while
> > 'TE_INFO' is of the colour that is expected with '= 10,'. You may want to
> > download the video and then play it, if Google Drive plays it at a resolution
> > that is lower than the video's native resolution.
> > 
> > Within this same session, there were other such enum constants with broken
> > highlighting, though they have not been captured in the video.
> > The termscript is attached at [2].
> > 
> > The graphics session is Wayland with swaywm as its compositor; XWayland is
> > not enabled. The terminal emulator is 'foot'. Another terminal emulator,
> > 'alacritty' was also tested; the problem occurred there too.
> > 
> > The problem doesn't seem to occur with small-sized files; After reducing the
> > vulkan_core.h to contain only around 235 lines, emacs was able to show the
> > (reduced) file with consistent highlighting.
> 
> FWIW, I cannot reproduce this with stock Emacs 29.3 and vulkan_core.h
> file that I downloaded from this site:
> 
>   https://github.com/KhronosGroup/dfdutils/blob/main/vulkan/vulkan_core.h

I see now that you say you see this with the master branch, so I
tested that version as well, and I still don't see the problem.