Helps #48601
Whenever an extension is installed, we call `register_grammars` even
when the grammar list is empty. This unnecessarily increments
reload_count and notifies the LSP store, which clears all languages and
triggers a full reparse.
Clearing languages also emits `LanguageChanged` events for buffers,
causing the editor to perform expensive recomputations (like
https://github.com/zed-industries/zed/pull/48622) which can block the
main thread for large multibuffers.
This PR addresses the empty-grammar case. If an extension actually adds
a grammar, the underlying issue still exists and will require additional
fixes to fully resolve.
- [ ] Tests or screenshots needed?
- [x] Code Reviewed
- [ ] Manual QA
Release Notes:
- Fixed an issue where installing theme extensions could block the main
thread
Marco Mihai Condrache
f1f8c5523b