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perf(editor): eliminate full string equality comparison on cursor movement in QueryaCodeEditor #1542
Description
Problem
In QueryaCodeEditor._onTextChanged (lib/core/editor/querya_code_editor.dart), _effectiveController.addListener(_onTextChanged) is triggered on every cursor position change, arrow key navigation, and text selection update.
When currentText.length == _lastText.length, the method performs a full (N)$ string equality check currentText == _lastText across the entire document.
For 100KB-1MB SQL scripts, every arrow key press or selection shift runs a heavy string scan, causing typing and navigation latency.
Solution
- Track
TextEditingValueand verify whether text actually changed vs selection/cursor changes. - Avoid full-document string comparison when text identity or selection-only changes occur.
Benefits
- 0 string scanning overhead during arrow key navigation and cursor selection in large documents.
- Smooth, instant cursor movements in heavy SQL scripts.
Activity
ZhuchkaTriplesix commentedon Oct 17, 2026
Closing: already handled.
QueryaCodeEditor._onTextChangedstarts withif (identical(currentText, _lastText)) return;. A caret move or selection change keeps the controller's text as the sameStringobject (onlyselectionchanges in the newTextEditingValue), so it returns there without scanning the document. The full==runs only when the text object changed and has the same length, i.e. an actual edit that replaced characters, and then it stops at the first difference.