Detect side-effects in tagged template expressions

src/ast/nodes/TaggedTemplateExpression.js

@@ -0,0 +1,43 @@
+import Node from '../Node.js';
+import isProgramLevel from '../utils/isProgramLevel.js';
+import callHasEffects from './shared/callHasEffects.js';
+
+export default class TaggedTemplateExpression extends Node {
+	bind ( scope ) {
+		if ( this.tag.type === 'Identifier' ) {
+			const declaration = scope.findDeclaration( this.tag.name );
+
+			if ( declaration.isNamespace ) {
+				this.module.error({
+					code: 'CANNOT_CALL_NAMESPACE',
+					message: `Cannot call a namespace ('${this.tag.name}')`
+				}, this.start );
+			}
+
+			if ( this.tag.name === 'eval' && declaration.isGlobal ) {
+				this.module.warn({
+					code: 'EVAL',
+					message: `Use of eval is strongly discouraged, as it poses security risks and may cause issues with minification`,
+					url: 'https://github.com/rollup/rollup/wiki/Troubleshooting#avoiding-eval'
+				}, this.start );
+			}
+		}
+
+		super.bind( scope );
+	}
+
+	hasEffects ( scope ) {
+		return this.quasi.hasEffects(scope) || callHasEffects( scope, this.tag, false );
+	}
+
+	initialise ( scope ) {
+		if ( isProgramLevel( this ) ) {
+			this.module.bundle.dependentExpressions.push( this );
+		}
+		super.initialise( scope );
+	}
+
+	isUsedByBundle () {
+		return this.hasEffects( this.findScope() );
+	}
+}

src/ast/nodes/index.js

@@ -28,6 +28,7 @@ import NewExpression from './NewExpression.js';
 import ObjectExpression from './ObjectExpression.js';
 import ReturnStatement from './ReturnStatement.js';
 import Statement from './shared/Statement.js';
+import TaggedTemplateExpression from './TaggedTemplateExpression.js';
 import TemplateLiteral from './TemplateLiteral.js';
 import ThisExpression from './ThisExpression.js';
 import ThrowStatement from './ThrowStatement.js';
@@ -68,6 +69,7 @@ export default {
 	ObjectExpression,
 	ReturnStatement,
 	SwitchStatement: Statement,
+	TaggedTemplateExpression,
 	TemplateLiteral,
 	ThisExpression,
 	ThrowStatement,

test/form/side-effects-in-template-literals/_config.js

@@ -0,0 +1,6 @@
+module.exports = {
+	description: 'detects side-effects in template literals and tagged template expressions',
+	options: {
+		moduleName: 'myBundle'
+	}
+};

test/form/side-effects-in-template-literals/_expected/amd.js

@@ -0,0 +1,27 @@
+define(['exports'], function (exports) { 'use strict';
+
+	exports.x = 0;
+
+	function noEffects() {}
+
+	function modifyX() {
+		return exports.x++;
+	}
+
+	const b = `${globalFunction()}has effects`;
+
+	const c = `${modifyX()}has effects`;
+
+	const e = noEffects`${globalFunction()}has effects`;
+
+	const f = noEffects`${modifyX()}has effects`;
+
+	const g = globalFunction`has effects`;
+
+	const h = globalFunction()`has effects`;
+
+	const i = modifyX`has effects`;
+
+	Object.defineProperty(exports, '__esModule', { value: true });
+
+});

test/form/side-effects-in-template-literals/_expected/cjs.js

@@ -0,0 +1,25 @@
+'use strict';
+
+Object.defineProperty(exports, '__esModule', { value: true });
+
+exports.x = 0;
+
+function noEffects() {}
+
+function modifyX() {
+	return exports.x++;
+}
+
+const b = `${globalFunction()}has effects`;
+
+const c = `${modifyX()}has effects`;
+
+const e = noEffects`${globalFunction()}has effects`;
+
+const f = noEffects`${modifyX()}has effects`;
+
+const g = globalFunction`has effects`;
+
+const h = globalFunction()`has effects`;
+
+const i = modifyX`has effects`;

test/form/side-effects-in-template-literals/_expected/es.js

@@ -0,0 +1,23 @@
+let x = 0;
+
+function noEffects() {}
+
+function modifyX() {
+	return x++;
+}
+
+const b = `${globalFunction()}has effects`;
+
+const c = `${modifyX()}has effects`;
+
+const e = noEffects`${globalFunction()}has effects`;
+
+const f = noEffects`${modifyX()}has effects`;
+
+const g = globalFunction`has effects`;
+
+const h = globalFunction()`has effects`;
+
+const i = modifyX`has effects`;
+
+export { x };

test/form/side-effects-in-template-literals/_expected/iife.js

@@ -0,0 +1,28 @@
+var myBundle = (function (exports) {
+	'use strict';
+
+	exports.x = 0;
+
+	function noEffects() {}
+
+	function modifyX() {
+		return exports.x++;
+	}
+
+	const b = `${globalFunction()}has effects`;
+
+	const c = `${modifyX()}has effects`;
+
+	const e = noEffects`${globalFunction()}has effects`;
+
+	const f = noEffects`${modifyX()}has effects`;
+
+	const g = globalFunction`has effects`;
+
+	const h = globalFunction()`has effects`;
+
+	const i = modifyX`has effects`;
+
+	return exports;
+
+}({}));

test/form/side-effects-in-template-literals/_expected/umd.js

@@ -0,0 +1,31 @@
+(function (global, factory) {
+	typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
+	typeof define === 'function' && define.amd ? define(['exports'], factory) :
+	(factory((global.myBundle = {})));
+}(this, (function (exports) { 'use strict';
+
+	exports.x = 0;
+
+	function noEffects() {}
+
+	function modifyX() {
+		return exports.x++;
+	}
+
+	const b = `${globalFunction()}has effects`;
+
+	const c = `${modifyX()}has effects`;
+
+	const e = noEffects`${globalFunction()}has effects`;
+
+	const f = noEffects`${modifyX()}has effects`;
+
+	const g = globalFunction`has effects`;
+
+	const h = globalFunction()`has effects`;
+
+	const i = modifyX`has effects`;
+
+	Object.defineProperty(exports, '__esModule', { value: true });
+
+})));

test/form/side-effects-in-template-literals/main.js

@@ -0,0 +1,27 @@
+let x = 0;
+
+function noEffects() {}
+
+function modifyX() {
+	return x++;
+}
+
+const a = `${noEffects()}is removed`;
+
+const b = `${globalFunction()}has effects`;
+
+const c = `${modifyX()}has effects`;
+
+const d = noEffects`is removed`;
+
+const e = noEffects`${globalFunction()}has effects`;
+
+const f = noEffects`${modifyX()}has effects`;
+
+const g = globalFunction`has effects`;
+
+const h = globalFunction()`has effects`;
+
+const i = modifyX`has effects`;
+
+export {x};