Fixes #32522: Set multiline flag on regex if replacing more than 1k matches

src/vs/editor/contrib/find/common/findModel.ts

@@ -409,6 +409,18 @@ export class FindModelBoundToEditorModel {
 			return;
 		}
 
+		let searchRegex = searchData.regex;
+		if (!searchRegex.multiline) {
+			let mod = 'm';
+			if (searchRegex.ignoreCase) {
+				mod += 'i';
+			}
+			if (searchRegex.global) {
+				mod += 'g';
+			}
+			searchRegex = new RegExp(searchRegex.source, mod);
+		}
+
 		const model = this._editor.getModel();
 		const modelText = model.getValue(editorCommon.EndOfLinePreference.LF);
 		const fullModelRange = model.getFullModelRange();
@@ -416,11 +428,11 @@ export class FindModelBoundToEditorModel {
 		const replacePattern = this._getReplacePattern();
 		let resultText: string;
 		if (replacePattern.hasReplacementPatterns) {
-			resultText = modelText.replace(searchData.regex, function () {
+			resultText = modelText.replace(searchRegex, function () {
 				return replacePattern.buildReplaceString(<string[]><any>arguments);
 			});
 		} else {
-			resultText = modelText.replace(searchData.regex, replacePattern.buildReplaceString(null));
+			resultText = modelText.replace(searchRegex, replacePattern.buildReplaceString(null));
 		}
 
 		let command = new ReplaceCommandThatPreservesSelection(fullModelRange, resultText, this._editor.getSelection());

src/vs/editor/contrib/find/test/common/findModel.test.ts

@@ -2004,6 +2004,29 @@ suite('FindModel', () => {
 		findState.dispose();
 	});
 
+	findTest('issue #32522 replaceAll with ^ on more than 1000 matches', (editor, cursor) => {
+		let initialText = '';
+		for (let i = 0; i < 1100; i++) {
+			initialText += 'line' + i + '\n';
+		}
+		editor.getModel().setValue(initialText);
+		let findState = new FindReplaceState();
+		findState.change({ searchString: '^', replaceString: 'a ', isRegex: true }, false);
+		let findModel = new FindModelBoundToEditorModel(editor, findState);
+
+		findModel.replaceAll();
+
+		let expectedText = '';
+		for (let i = 0; i < 1100; i++) {
+			expectedText += 'a line' + i + '\n';
+		}
+		expectedText += 'a ';
+		assert.equal(editor.getModel().getValue(), expectedText);
+
+		findModel.dispose();
+		findState.dispose();
+	});
+
 	findTest('issue #19740 Find and replace capture group/backreference inserts `undefined` instead of empty string', (editor, cursor) => {
 		let findState = new FindReplaceState();
 		findState.change({ searchString: 'hello(z)?', replaceString: 'hi$1', isRegex: true, matchCase: true }, false);