Template Parts link leads to a Site Editor with just a loading icon in hybrid theme.

[aurooba]

Description

I've got a hybrid (non-block) theme that has Template Parts enabled. When you go to Appearance > Template Parts, you get a loading screen or an error, instead of the expected Template Parts screen.

Step-by-step reproduction instructions

1. on 6.2-beta3-55418 version of WordPress
2. Install a regular theme that has Template Parts support enabled and at least 1 Template Part
3. Go to Appearance > Template Parts
4. See the loading screen
5. Refresh the page, get the error: The theme you are currently using is not compatible with the Site Editor.

Screenshots, screen recording, code snippet

If you refresh the page, you get the following error: The theme you are currently using is not compatible with the Site Editor.

Environment info

WordPress: 6.2-beta3-55418 version of WordPress
Gutenberg: Tested with Gutenberg and without Gutenberg
Browser: Google Chrome

Please confirm that you have searched existing issues in the repo.

Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

Yes

[ndiego]

@aurooba does it look like #48292 could be a similar issue?

[aurooba]

@ndiego Ooh yes. This is definitely connected. But in this case, we wouldn't want the front page to load anyway, we want it to take us directly to the Template Parts page. Should I add my feedback/notes to #48292 and close this here?

[ndiego]

Let's leave this open until we are 100% sure it's the same root issue. If you have time to add feedback on the other issue, that would be awesome. 🙏

[Mamaduka]

Fixed via #48343 and will be included in the next beta. We also have an E2E test for this feature, so we should catch similar regressions early.