Merge pull request #124 from rollup/gh-112

Include statements with side-effects

src/Bundle.js

@@ -67,6 +67,11 @@ export default class Bundle {
 				entryModule.markAllStatements( true );
 				entryModule.markAllExports();
 
+				// Include all side-effects
+				this.modules.forEach( module => {
+					module.markAllSideEffects();
+				});
+
 				// Sort the modules.
 				this.orderedModules = this.sort();
 

src/Module.js

@@ -437,6 +437,12 @@ export default class Module {
 		this.markAllExports();
 	}
 
+	markAllSideEffects () {
+		this.statements.forEach( statement => {
+			statement.markSideEffect();
+		});
+	}
+
 	markAllStatements ( isEntryModule ) {
 		this.statements.forEach( statement => {
 			if ( statement.isIncluded ) return; // TODO can this happen? probably not...

src/Statement.js

@@ -8,6 +8,11 @@ const blockDeclarations = {
 	'let': true
 };
 
+const modifierNodes = {
+	AssignmentExpression: 'left',
+	UpdateExpression: 'argument'
+};
+
 function isIife ( node, parent ) {
 	return parent && parent.type === 'CallExpression' && node === parent.callee;
 }
@@ -392,6 +397,29 @@ export default class Statement {
 		});
 	}
 
+	markSideEffect () {
+		const statement = this;
+
+		walk( this.node, {
+			enter ( node, parent ) {
+				if ( /Function/.test( node.type ) && !isIife( node, parent ) ) return this.skip();
+
+				// If this is a top-level call expression, or an assignment to a global,
+				// this statement will need to be marked
+				if ( node.type === 'CallExpression' ) {
+					statement.mark();
+				}
+
+				else if ( node.type in modifierNodes ) {
+					let subject = node[ modifierNodes[ node.type ] ];
+					while ( subject.type === 'MemberExpression' ) subject = subject.object;
+
+					if ( statement.module.bundle.globals.defines( subject.name ) ) statement.mark();
+				}
+			}
+		});
+	}
+
 	replaceIdentifiers ( magicString, names, bundleExports ) {
 		const statement = this;
 

test/form/unused-side-effect/_config.js

@@ -0,0 +1,3 @@
+module.exports = {
+	description: 'side-effects to non-globals are not blindly included'
+};

test/form/unused-side-effect/_expected/amd.js

@@ -0,0 +1,7 @@
+define(function () { 'use strict';
+
+	var foo = 42;
+
+	assert.equal( foo, 42 );
+
+});

test/form/unused-side-effect/_expected/cjs.js

@@ -0,0 +1,5 @@
+'use strict';
+
+var foo = 42;
+
+assert.equal( foo, 42 );

test/form/unused-side-effect/_expected/es6.js

@@ -0,0 +1,3 @@
+var foo = 42;
+
+assert.equal( foo, 42 );

test/form/unused-side-effect/_expected/iife.js

@@ -0,0 +1,7 @@
+(function () { 'use strict';
+
+	var foo = 42;
+
+	assert.equal( foo, 42 );
+
+})();

test/form/unused-side-effect/_expected/umd.js

@@ -0,0 +1,11 @@
+(function (global, factory) {
+	typeof exports === 'object' && typeof module !== 'undefined' ? factory() :
+	typeof define === 'function' && define.amd ? define(factory) :
+	factory();
+}(this, function () { 'use strict';
+
+	var foo = 42;
+
+	assert.equal( foo, 42 );
+
+}));

test/form/unused-side-effect/foo.js

@@ -0,0 +1,13 @@
+var uid = 0;
+uid = 1;
+uid += 1;
+uid++;
+
+// ensure identifiers aren't treated as globals just because
+// var declaration hasn't been encountered yet...
+uid2 = 1;
+uid2 += 1;
+uid2++;
+var uid2;
+
+export var foo = 42;

test/form/unused-side-effect/main.js

@@ -0,0 +1,2 @@
+import { foo } from './foo';
+assert.equal( foo, 42 );

test/function/globally-called-modifying-function/_config.js

@@ -0,0 +1,3 @@
+module.exports = {
+	description: 'globally called function should be included if it modifies an exported value (#112)'
+};

test/function/globally-called-modifying-function/main.js

@@ -0,0 +1,3 @@
+import value from './module.js';
+
+assert.equal( value, 3 );

test/function/globally-called-modifying-function/module.js

@@ -0,0 +1,17 @@
+var value = 1;
+
+function change () {
+	value = 2;
+}
+
+function changeAgain () {
+	value += 1;
+}
+
+change();
+
+if ( true ) {
+	changeAgain();
+}
+
+export default value;

test/function/modify-assumed-global/_config.js

@@ -0,0 +1,14 @@
+var assert = require( 'assert' );
+
+var Math = {};
+
+module.exports = {
+	description: 'side-effects to assumed globals are included',
+	context: {
+		Math: Math
+	},
+	exports: function ( exports ) {
+		assert.equal( Math.square( 3 ), 9 );
+		assert.equal( Math.cube( 3 ), 27 );
+	}
+};

test/function/modify-assumed-global/main.js

@@ -0,0 +1,3 @@
+import { square } from './math';
+
+assert.equal( square( 2 ), 4 );

test/function/modify-assumed-global/math.js

@@ -0,0 +1,15 @@
+function square ( x ) {
+	return x * x;
+}
+
+function cube ( x ) {
+	return x * x * x;
+}
+
+Math.square = square;
+
+if ( true ) {
+	Math.cube = cube;
+}
+
+export { square };