Repository navigation
perf(editor): cache root TextSpan in QueryaHighlightController to eliminate allocations on cursor blinks #1544
Description
Problem
In QueryaHighlightController.buildTextSpan (lib/core/editor/querya_highlight_controller.dart), buildTextSpan is invoked twice per second for cursor blink repaints.
Even on a full cache hit (_cachedText == text), it unconditionally allocates a new wrapper TextSpan and a new List<TextSpan> (TextSpan(style: style, children: [_cachedSpan!])).
Over a session, background cursor blinks across multiple open editor tabs churn unnecessary garbage collection cycles.
Solution
- Cache the outer root
TextSpandirectly (_cachedRootSpan), invalidating it only when the text content, base style, or theme brightness changes. - Return the cached root span directly on cache hits without allocating a new wrapper
TextSpanor children list.
Benefits
- 0 allocations per cursor blink cycle on idle editors.
- Reduced GC pressure when multiple SQL editor tabs are active.
Activity
ZhuchkaTriplesix commentedon Oct 17, 2026
Closing as not worth doing. Checked against the code and the Flutter sources:
buildTextSpan. EditableText blinks by changing the cursor opacity on the RenderEditable; it does not rebuild.buildTextSpanruns on rebuilds such as text, selection and focus changes.TextSpancosts one object and a one-element list.RenderEditable.textcompares it with==.TextSpan ==compares the children withlistEquals, and the only child is the cached_cachedSpanitself, so the comparison ends atidenticalin O(1) and no relayout follows.Caching the root would save those two small allocations per rebuild and nothing measurable. #1522 is the same proposal and is closed with this.