TypeError when switching to PHP8

[onetrev]

I just tried moving my Grav 1.7.15 from PHP 7.4 to PHP8, and upon doing so I get the following error in /system/src/Grav/Common/Themes.php

"method_exists(): Argument #1 ($object_or_class) must be of type object|string, int given"

Anything I can do to fix this, or if not help troubleshoot this further? Thank you!

NOTE: I just created a new Grav site on the same server, it's running on PHP 8 too, and all is good with that site.

[mahagr]

It must be theme specific error. Nonetheless, I think there's room to improve the checks.

[onetrev]

Excellent. Ya, this would be great because right now I can't see any info in there that gives me any indication it was my theme that way the problem, sorry, and more importantly I can't see where my error is. :( So that's going to be tricky to troubleshoot.

PS, love the work you guys are doing. I have the NextGen Editor running my custom theme (that is broken in PHP 8). And I just picked up Typhoon for my wife's site.

UPDATE: fixed! The issue was that in mytheme.php (clgrav.php in my case) the theme name in class MyTheme extends Theme was not the correct name. Used to work in PHP 7 but I guess PHP 8 is more picky. :)