Fix: update selection format and style on programmatic select

packages/lexical/src/__tests__/unit/LexicalSelection.test.ts

@@ -61,6 +61,44 @@ function mapLatest<T extends LexicalNode>(nodes: T[]): T[] {
 
 describe('LexicalSelection tests', () => {
   initializeUnitTest(testEnv => {
+    test('programmatic selection movement clears stale formatting', async () => {
+      const {editor} = testEnv;
+
+      await editor.update(() => {
+        const root = $getRoot();
+        const paragraph = $createParagraphNode();
+        const text = $createTextNode('Hello World');
+        paragraph.append(text);
+        root.append(paragraph);
+
+        // 1. Bold "Hello" (first 5 chars)
+        text.select(0, 5);
+        const selection = $getSelection();
+        if ($isRangeSelection(selection)) {
+          selection.formatText('bold');
+        }
+      });
+
+      await editor.update(() => {
+        const selection = $getSelection();
+        // Verify we are indeed bold
+        if ($isRangeSelection(selection)) {
+          expect(selection.hasFormat('bold')).toBe(true);
+        }
+
+        // 2. Jump to the end (the unformatted " World" text)
+        $getRoot().selectEnd();
+      });
+
+      await editor.update(() => {
+        const selection = $getSelection();
+        // 3. Verification: format cache must be flushed
+        if ($isRangeSelection(selection)) {
+          expect(selection.hasFormat('bold')).toBe(false);
+        }
+      });
+    });
+
     describe('Inserting text either side of inline elements', () => {
       const setup = async (
         mode: 'start-of-paragraph' | 'mid-paragraph' | 'end-of-paragraph',

packages/lexical/src/nodes/LexicalTextNode.ts

@@ -897,6 +897,9 @@ export class TextNode extends LexicalNode implements InlineFormattableNode {
         'text',
       );
     } else {
+      const isDifferentNode =
+        selection.anchor.key !== key || selection.focus.key !== key;
+
       const compositionKey = $getCompositionKey();
       if (
         compositionKey === selection.anchor.key ||
@@ -905,6 +908,11 @@ export class TextNode extends LexicalNode implements InlineFormattableNode {
         $setCompositionKey(key);
       }
       selection.setTextNodeRange(this, anchorOffset, this, focusOffset);
+
+      if (isDifferentNode) {
+        selection.format = this.getFormat();
+        selection.style = this.getStyle();
+      }
     }
     return selection;
   }