feat(vscode): conservatively modify formatting ranges (#5851)

Author: johnsoncodehk

extensions/vscode/lib/rangeFormatting.ts

@@ -54,8 +54,8 @@ function getTrimmedNewText(
 		};
 	}
 	const oldText = document.getText(edit.range);
-	const overlapStart = Math.max(editStart, selectionStart) - editStart;
-	const overlapEnd = Math.min(editEnd, selectionEnd) - editStart;
+	let overlapStart = Math.max(editStart, selectionStart) - editStart;
+	let overlapEnd = Math.min(editEnd, selectionEnd) - editStart;
 	if (overlapStart === overlapEnd) {
 		return;
 	}
@@ -64,19 +64,23 @@ function getTrimmedNewText(
 	let newTextIndex = 0;
 	let newStart!: number;
 	let newEnd!: number;
-
 	while (true) {
 		if (oldTextIndex === overlapStart) {
 			newStart = newTextIndex;
 			break;
 		}
 		const oldCharCode = oldText.charCodeAt(oldTextIndex);
 		const newCharCode = edit.newText.charCodeAt(newTextIndex);
-		if (oldCharCode === newCharCode || (!isWhitespaceChar(oldCharCode) && !isWhitespaceChar(newCharCode))) {
+		if (oldCharCode === newCharCode) {
 			oldTextIndex++;
 			newTextIndex++;
 			continue;
 		}
+		if (!isWhitespaceChar(oldCharCode) && !isWhitespaceChar(newCharCode)) {
+			newStart = newTextIndex;
+			overlapStart -= overlapStart - oldTextIndex;
+			break;
+		}
 		if (isWhitespaceChar(oldCharCode)) {
 			oldTextIndex++;
 		}
@@ -94,11 +98,16 @@ function getTrimmedNewText(
 		}
 		const oldCharCode = oldText.charCodeAt(oldTextIndex);
 		const newCharCode = edit.newText.charCodeAt(newTextIndex);
-		if (oldCharCode === newCharCode || (!isWhitespaceChar(oldCharCode) && !isWhitespaceChar(newCharCode))) {
+		if (oldCharCode === newCharCode) {
 			oldTextIndex--;
 			newTextIndex--;
 			continue;
 		}
+		if (!isWhitespaceChar(oldCharCode) && !isWhitespaceChar(newCharCode)) {
+			newEnd = newTextIndex + 1;
+			overlapEnd += overlapEnd - oldTextIndex + 1;
+			break;
+		}
 		if (isWhitespaceChar(oldCharCode)) {
 			oldTextIndex--;
 		}

extensions/vscode/tests/rangeFormatting.spec.ts

@@ -8,7 +8,7 @@ describe('provideDocumentRangeFormattingEdits', () => {
 		const selection = createRange(1, 5);
 		const edits = [createTextEdit(0, 5, '_BCDE')];
 		const result = restrictFormattingEditsToRange(document, selection, edits, createTextEdit);
-		expect(applyEdits(document, result)).toMatchInlineSnapshot(`"0BCDE5"`);
+		expect(applyEdits(document, result)).toMatchInlineSnapshot(`"_BCDE5"`);
 	});
 
 	test('keeps indent when edits start on previous line', () => {
@@ -89,7 +89,7 @@ describe('provideDocumentRangeFormattingEdits', () => {
 		const selection = createRange(1, 5); // select "bcde"
 		const edits = [createTextEdit(0, 6, 'ab')]; // replace all with just "ab"
 		const result = restrictFormattingEditsToRange(document, selection, edits, createTextEdit);
-		expect(applyEdits(document, result)).toMatchInlineSnapshot(`"af"`);
+		expect(applyEdits(document, result)).toMatchInlineSnapshot(`"ab"`);
 	});
 
 	test('handles insertion where newText is longer than oldText', () => {
@@ -164,7 +164,7 @@ describe('provideDocumentRangeFormattingEdits', () => {
 		const selection = createRange(1, 3); // select "好世"
 		const edits = [createTextEdit(0, 4, '你好朋友')];
 		const result = restrictFormattingEditsToRange(document, selection, edits, createTextEdit);
-		expect(applyEdits(document, result)).toMatchInlineSnapshot(`"你好朋界"`);
+		expect(applyEdits(document, result)).toMatchInlineSnapshot(`"你好朋友"`);
 	});
 
 	test('handles overlapStart equals overlapEnd', () => {