Merge from master

src/vs/editor/test/common/model/textModelWithTokens.test.ts

@@ -2,20 +2,19 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *  Licensed under the Source EULA. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
-'use strict';
 
 import * as assert from 'assert';
-import { TextModel } from 'vs/editor/common/model/textModel';
 import { IDisposable } from 'vs/base/common/lifecycle';
-import { ViewLineToken } from 'vs/editor/test/common/core/viewLineToken';
-import { ITokenizationSupport, TokenizationRegistry, LanguageId, LanguageIdentifier, MetadataConsts } from 'vs/editor/common/modes';
-import { CharacterPair } from 'vs/editor/common/modes/languageConfiguration';
-import { Range } from 'vs/editor/common/core/range';
 import { Position } from 'vs/editor/common/core/position';
+import { Range } from 'vs/editor/common/core/range';
+import { TokenizationResult2 } from 'vs/editor/common/core/token';
 import { IFoundBracket } from 'vs/editor/common/model';
+import { TextModel } from 'vs/editor/common/model/textModel';
+import { ITokenizationSupport, LanguageId, LanguageIdentifier, MetadataConsts, TokenizationRegistry } from 'vs/editor/common/modes';
+import { CharacterPair } from 'vs/editor/common/modes/languageConfiguration';
 import { LanguageConfigurationRegistry } from 'vs/editor/common/modes/languageConfigurationRegistry';
 import { NULL_STATE } from 'vs/editor/common/modes/nullMode';
-import { TokenizationResult2 } from 'vs/editor/common/core/token';
+import { ViewLineToken } from 'vs/editor/test/common/core/viewLineToken';
 
 suite('TextModelWithTokens', () => {
 
@@ -159,7 +158,7 @@ suite('TextModelWithTokens - bracket matching', () => {
 	}
 
 	const languageIdentifier = new LanguageIdentifier('bracketMode1', LanguageId.PlainText);
-	let registration: IDisposable = null;
+	let registration: IDisposable | null = null;
 
 	setup(() => {
 		registration = LanguageConfigurationRegistry.register(languageIdentifier, {
@@ -391,6 +390,34 @@ suite('TextModelWithTokens regression tests', () => {
 		model.dispose();
 		registration.dispose();
 	});
+
+	test('issue #63822: Wrong embedded language detected for empty lines', () => {
+		const outerMode = new LanguageIdentifier('outerMode', 3);
+		const innerMode = new LanguageIdentifier('innerMode', 4);
+
+		const tokenizationSupport: ITokenizationSupport = {
+			getInitialState: () => NULL_STATE,
+			tokenize: undefined,
+			tokenize2: (line, state) => {
+				let tokens = new Uint32Array(2);
+				tokens[0] = 0;
+				tokens[1] = (
+					innerMode.id << MetadataConsts.LANGUAGEID_OFFSET
+				) >>> 0;
+				return new TokenizationResult2(tokens, state);
+			}
+		};
+
+		let registration = TokenizationRegistry.register(outerMode.language, tokenizationSupport);
+
+		let model = TextModel.createFromString('A model with one line', undefined, outerMode);
+
+		model.forceTokenization(1);
+		assert.equal(model.getLanguageIdAtPosition(1, 1), innerMode.id);
+
+		model.dispose();
+		registration.dispose();
+	});
 });
 
 suite('TextModel.getLineIndentGuide', () => {