Fix indentation after string literals containing escaped characters (#6440)

* Update indent regex
* Prettier formatting
* Add regex tests
* Undo prettier changes
* Forgot some
* One more
* Simplify & fix tests
* More descriptive comment
* Move language config to another file
* Remove unneeded tslint disable rule

Author: kimadeline

news/2 Fixes/4241.md

@@ -0,0 +1 @@
+Fix indentation after string literals containing escaped characters.

src/client/extension.ts

@@ -25,7 +25,6 @@ import {
     Disposable,
     ExtensionContext,
     extensions,
-    IndentAction,
     languages,
     Memento,
     OutputChannel,
@@ -41,7 +40,7 @@ import { registerTypes as appRegisterTypes } from './application/serviceRegistry
 import { IApplicationDiagnostics } from './application/types';
 import { DebugService } from './common/application/debugService';
 import { IApplicationShell, ICommandManager, IWorkspaceService } from './common/application/types';
-import { Commands, isTestExecution, PYTHON, PYTHON_LANGUAGE, STANDARD_OUTPUT_CHANNEL } from './common/constants';
+import { Commands, isTestExecution, PYTHON, STANDARD_OUTPUT_CHANNEL } from './common/constants';
 import { registerTypes as registerDotNetTypes } from './common/dotnet/serviceRegistry';
 import { registerTypes as installerRegisterTypes } from './common/installer/serviceRegistry';
 import { traceError } from './common/logger';
@@ -86,6 +85,7 @@ import { registerTypes as interpretersRegisterTypes } from './interpreter/servic
 import { ServiceContainer } from './ioc/container';
 import { ServiceManager } from './ioc/serviceManager';
 import { IServiceContainer, IServiceManager } from './ioc/types';
+import { setLanguageConfiguration } from './language/languageConfiguration';
 import { LinterCommands } from './linters/linterCommands';
 import { registerTypes as lintersRegisterTypes } from './linters/serviceRegistry';
 import { ILintingEngine } from './linters/types';
@@ -173,30 +173,7 @@ async function activateUnsafe(context: ExtensionContext): Promise<IExtensionApi>
     const linterProvider = new LinterProvider(context, serviceManager);
     context.subscriptions.push(linterProvider);
 
-    // Enable indentAction
-    // tslint:disable-next-line:no-non-null-assertion
-    languages.setLanguageConfiguration(PYTHON_LANGUAGE, {
-        onEnterRules: [
-            {
-                beforeText: /^\s*(?:def|class|for|if|elif|else|while|try|with|finally|except|async)\b.*:\s*/,
-                action: { indentAction: IndentAction.Indent }
-            },
-            {
-                beforeText: /^(?!\s+\\)[^#\n]+\\\s*/,
-                action: { indentAction: IndentAction.Indent }
-            },
-            {
-                beforeText: /^\s*#.*/,
-                afterText: /.+$/,
-                action: { indentAction: IndentAction.None, appendText: '# ' }
-            },
-            {
-                beforeText: /^\s+(continue|break|return)\b.*/,
-                afterText: /\s+$/,
-                action: { indentAction: IndentAction.Outdent }
-            }
-        ]
-    });
+    setLanguageConfiguration();
 
     if (pythonSettings && pythonSettings.formatting && pythonSettings.formatting.provider !== 'internalConsole') {
         const formatProvider = new PythonFormattingEditProvider(context, serviceContainer);

src/client/language/languageConfiguration.ts

@@ -0,0 +1,34 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+'use strict';
+
+import { IndentAction, languages } from 'vscode';
+import { PYTHON_LANGUAGE } from '../common/constants';
+
+export const MULTILINE_SEPARATOR_INDENT_REGEX = /^(?!\s+\\)[^#\n]+\\$/;
+
+export function setLanguageConfiguration() {
+    // Enable indentAction
+    languages.setLanguageConfiguration(PYTHON_LANGUAGE, {
+        onEnterRules: [
+            {
+                beforeText: /^\s*(?:def|class|for|if|elif|else|while|try|with|finally|except|async)\b.*:\s*/,
+                action: { indentAction: IndentAction.Indent }
+            },
+            {
+                beforeText: MULTILINE_SEPARATOR_INDENT_REGEX,
+                action: { indentAction: IndentAction.Indent }
+            },
+            {
+                beforeText: /^\s*#.*/,
+                afterText: /.+$/,
+                action: { indentAction: IndentAction.None, appendText: '# ' }
+            },
+            {
+                beforeText: /^\s+(continue|break|return)\b.*/,
+                afterText: /\s+$/,
+                action: { indentAction: IndentAction.Outdent }
+            }
+        ]
+    });
+}

src/test/language/languageConfiguration.unit.test.ts

@@ -0,0 +1,23 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+'use strict';
+
+import { expect } from 'chai';
+
+import { MULTILINE_SEPARATOR_INDENT_REGEX } from '../../client/language/languageConfiguration';
+
+suite('Language configuration regexes', () => {
+    test('Multiline separator indent regex should not pick up strings with no multiline separator', async () => {
+        const result = MULTILINE_SEPARATOR_INDENT_REGEX.test('a = "test"');
+        expect (result).to.be.equal(false, 'Multiline separator indent regex for regular strings should not have matches');
+    });
+    test('Multiline separator indent regex should not pick up strings with escaped characters', async () => {
+        const result = MULTILINE_SEPARATOR_INDENT_REGEX.test('a = \'hello \\n\'');
+        expect (result).to.be.equal(false, 'Multiline separator indent regex for strings with escaped characters should not have matches');
+    });
+    test('Multiline separator indent regex should pick up strings ending with a multiline separator', async () => {
+        const result = MULTILINE_SEPARATOR_INDENT_REGEX.test('a = \'multiline \\');
+        expect (result).to.be.equal(true, 'Multiline separator indent regex for strings with newline separator should have matches');
+    });
+});