Implement use strict linting (#7223)

* implement use strict linting

* commit changes

* add additional check for strict

build/gulpfile.hygiene.js

@@ -189,20 +189,10 @@ const tslintBaseFilter = [
 	'!extensions/vscode-api-tests/testWorkspace2/**',
 	'!extensions/**/*.test.ts',
 	'!extensions/html-language-features/server/lib/jquery.d.ts',
-	// {{SQL CARBON EDIT}}
-	'!extensions/big-data-cluster/src/bigDataCluster/controller/apiGenerated.ts'
+	'!extensions/big-data-cluster/src/bigDataCluster/controller/apiGenerated.ts' // {{SQL CARBON EDIT}}
 ];
 
-// {{SQL CARBON EDIT}}
-// const useStrictFilter = [
-// 	'src/**'
-// ];
-
-const sqlFilter = [
-	'src/sql/**'
-];
-
-// {{SQL CARBON EDIT}}
+const sqlFilter = ['src/sql/**']; // {{SQL CARBON EDIT}}
 
 const tslintCoreFilter = [
 	'src/**/*.ts',
@@ -336,23 +326,6 @@ function hygiene(some) {
 		this.emit('data', file);
 	});
 
-	// {{SQL CARBON EDIT}}
-	// Check for unnecessary 'use strict' lines. These are automatically added by the alwaysStrict compiler option so don't need to be added manually
-	// const useStrict = es.through(function (file) {
-	// 	const lines = file.__lines;
-	// 	// Only take the first 10 lines to reduce false positives- the compiler will throw an error if it's not the first non-comment line in a file
-	// 	// (10 is used to account for copyright and extraneous newlines)
-	// 	lines.slice(0, 10).forEach((line, i) => {
-	// 		if (/\s*'use\s*strict\s*'/.test(line)) {
-	// 			console.error(file.relative + '(' + (i + 1) + ',1): Unnecessary \'use strict\' - this is already added by the compiler');
-	// 			errorCount++;
-	// 		}
-	// 	});
-
-	// 	this.emit('data', file);
-	// });
-	// {{SQL CARBON EDIT}} END
-
 	const formatting = es.map(function (file, cb) {
 		tsfmt.processString(file.path, file.contents.toString('utf8'), {
 			verify: false,

build/lib/tslint/noUselessStrictRule.js

@@ -0,0 +1,28 @@
+"use strict";
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the Source EULA. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+Object.defineProperty(exports, "__esModule", { value: true });
+const Lint = require("tslint");
+class Rule extends Lint.Rules.TypedRule {
+    applyWithProgram(sourceFile, program) {
+        if (program.getCompilerOptions().alwaysStrict) {
+            return this.applyWithWalker(new NoUselessStrictRuleWalker(sourceFile, this.getOptions()));
+        }
+        return [];
+    }
+}
+exports.Rule = Rule;
+class NoUselessStrictRuleWalker extends Lint.RuleWalker {
+    visitStringLiteral(node) {
+        this.checkStringLiteral(node);
+        super.visitStringLiteral(node);
+    }
+    checkStringLiteral(node) {
+        const text = node.getText();
+        if (text === '\'use strict\'' || text === '"use strict"') {
+            this.addFailureAtNode(node, 'use strict directive is unnecessary');
+        }
+    }
+}

build/lib/tslint/noUselessStrictRule.ts

@@ -0,0 +1,30 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the Source EULA. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import * as Lint from 'tslint';
+import * as ts from 'typescript';
+
+export class Rule extends Lint.Rules.TypedRule {
+    public applyWithProgram(sourceFile: ts.SourceFile, program: ts.Program): Lint.RuleFailure[] {
+		if (program.getCompilerOptions().alwaysStrict) {
+			return this.applyWithWalker(new NoUselessStrictRuleWalker(sourceFile, this.getOptions()));
+		}
+		return [];
+	}
+}
+
+class NoUselessStrictRuleWalker extends Lint.RuleWalker {
+	protected visitStringLiteral(node: ts.StringLiteral): void {
+		this.checkStringLiteral(node);
+		super.visitStringLiteral(node);
+	}
+
+	private checkStringLiteral(node: ts.StringLiteral): void {
+		const text = node.getText();
+		if (text === '\'use strict\'' || text === '"use strict"') {
+			this.addFailureAtNode(node, 'use strict directive is unnecessary');
+		}
+	}
+}

tslint.json

@@ -228,7 +228,8 @@
 		"no-new-buffer": true,
 		"translation-remind": true,
 		"no-standalone-editor": true,
-		"no-nls-in-standalone-editor": true
+		"no-nls-in-standalone-editor": true,
+		"no-useless-strict": true
 	},
 	"defaultSeverity": "warning"
 }