Editor loading state shows flash of incorrect rendering mode

[fabiankaegy]

With some of the changes we recently applied to the "default rendering mode" we have introduced a regression in the loading state of the editor.

Previously the editor waited till the post / template etc was resolved before the editor canvas was actually shown. This no longer seems to be the case which now means the editor canvas renders before all the items are available and even when the default rendering mode is set to template-locked the editor first renders in post-only mode for a second before it switches over.

CleanShot.2025-01-17.at.13.55.55.mp4

Expected behavior

Ideally, we get back to the state where the editor shows a loading indicator till the canvas is really ready and doesn't show the incorrect rendering mode state.

[fabiankaegy]

I believe this was introduced in https://github.com/WordPress/gutenberg/pull/68549/files#diff-d364bf913a3b8f8eb8f79e2b52c75bd4130248c5a7c94fe021dc39602b19b697

CC: @Mamaduka

[Mamaduka]

I think regression was accidentally introduced in #68110, which delays the setting the default rendering mode until the template is loaded.

[Mayank-Tripathi32]

I think regression was accidentally introduced in #68110, which delays the setting the default rendering mode until the template is loaded.

Hey @Mamaduka @fabiankaegy , I tried looking through the linked PR and doing following seems to fix the issue, not sure if its the correct way though.

Changing

 defaultMode:  hasTemplate && hasDefaultMode ? _defaultMode: 'post-only',

to

defaultMode: hasDefaultMode ? _defaultMode: 'post-only',

This essentially removes the check for template and avoid the flash from 'post-only' mode.

loading.issue.mov

I will open up a Draft PR to see if it passes cli tests.

[Mamaduka]

Thanks for giving this a try, @Mayank-Tripathi32! Unfortunately, we can't just remove the hasTemplate condition. The #68110 explains why it's needed.

I'm afraid fixing this requires a bit more refactoring.