🐞 Flickering on cursor move and text editing

[nkleemann]

Description

Since 0.10.0 the syntax highlighting flickers on and off for a split second for any action performed inside the view, meaning:

• arrow keys (navigation)
• space, return
• text insert / delete

This was not the case with the previous version of CodeEditSourceEditor (0.9x)

To Reproduce

1. Create a CodeEditSourceEditor instance where text is handled by a @Obsersvable viewmodel and start to edit text

Expected Behavior

The syntax highlighting should not flicker.

Version Information

CodeEditSourceEditor: [e.g. 0.10.0]
macOS: 14.7 (23H124)
Xcode: Version 16.2 (16C5032a)

Additional Context

No response

Screenshots

See video:

Screen.Recording.2025-02-05.at.08.53.45.mov

[huyphams]

Same issue, I'm testing the example and it is flickering. Looks like it's trying to set highlight provider non-stop

Also the example is completely broken, as it always use plaintext and not support dark theme (I barely see the gutter in dark theme).

  if !areHighlightProvidersEqual(controller: controller) {
        controller.setHighlightProviders(highlightProviders)
  }

[austincondiff]

I have personally not experienced this as of recent. @thecoolwinter has this been fixed recently?

[thecoolwinter]

I don't think this has been fixed. Iirc 10.0 introduced a new api that diffs highlight providers. It sounds like that's accidental resetting the default tree sitter highlighter when text changes.

As a temporary workaround, use a state variable to make a TreeSitterClient and pass it to the editor. That'll keep it around while typing.

@State var treeSitterClient = TreeSitterClient

//...

CodeEditSourceEditor(
    //...
    highlightProviders: [treeSitterClient],
    //...
)

[thecoolwinter]

I've got a fix for this, my hunch was correct that there was some mismanagement of the default tree sitter highlight provider. I've opened a PR to make CESE correctly detect when the default highlight provider is wanted, and to keep around the tree-sitter provider between view updates.