WiX 4.0.5 -> 5.0.0 Regression

[chrpai]

My IsWiX tool has a custom project template for internal ui bootstrapper application. It includes a clone of the iupreq.thm and iuipreq.wxl to make it easy to customize. It builds and runs using WiX 4.0.5 but when I built it in 5.0.0 it succeeds but then fails to run.

[42E8:096C][2024-07-09T16:00:53]e000: Error 0x80070057: Failed to load theme from path: C:\Users\chrpai\AppData\Local\Temp{8D89D44D-9E53-407F-A1C4-6689DC94BA41}.ba\wixpreq.thm
[42E8:096C][2024-07-09T16:00:53]e000: Error 0x80070057: Failed to initialize theme.
[42E8:2BEC][2024-07-09T16:00:53]i500: Shutting down, exit code: 0x57
[42E8:096C][2024-07-09T16:00:53]i000: The prerequisites were not successfully installed, error: 0x0. The bootstrapper application will be not reloaded.

I searched through the Burn source and I found the issue. mbqpreq.png was renamed to wixpreq.png. If I pull the latest iuipreq.thm into the project it builds and runs successfully. The error message says it couldn't load the theme which is partially true... it's loaded but dependencies are not found.

I wanted to start this as a discussion before filing an issue.

Thanks,
Chris

[bevanweiss]

Would your interpretation of the 'theme' not include things like images, custom fonts, etc that are part of the visual styling?

There probably should have been an error message specifically about the file that was missed.
There definitely wasn't such a message before the 'Failed to load theme...' error?