Invalidate module when file content is changed

src/Bundle.js

@@ -181,7 +181,13 @@ export default class Bundle {
 				throw new Error( `Error loading ${id}: load hook should return a string, a { code, map } object, or nothing/null` );
 			})
 			.then( source => {
-				if (this.cachedModules && this.cachedModules[id]) {
+				if ( typeof source === 'string' ) {
+					source = {
+						code: source,
+						ast: null
+					};
+				}
+				if (this.cachedModules && this.cachedModules[id] && this.cachedModules[id].originalCode === source.code) {
 					const { code, originalCode } = this.cachedModules[id];
 					return {
 						code,

src/utils/transform.js

@@ -3,13 +3,6 @@ import Promise from 'es6-promise/lib/es6-promise/promise.js';
 export default function transform ( source, id, transformers ) {
 	let sourceMapChain = [];
 
-	if ( typeof source === 'string' ) {
-		source = {
-			code: source,
-			ast: null
-		};
-	}
-
 	let originalCode = source.code;
 	let ast = source.ast;
 

test/incremental/transform-changed/expected.js

@@ -0,0 +1,5 @@
+function foo () {
+	console.log('foo-changed');
+};
+
+foo();

test/incremental/transform-changed/foo-changed.js

@@ -0,0 +1,3 @@
+export default function () {
+	console.log('foo-changed');
+};

test/incremental/transform-changed/foo.js

@@ -0,0 +1,3 @@
+export default function () {
+	console.log('foo');
+};

test/incremental/transform-changed/main.js

@@ -0,0 +1,3 @@
+import foo from './foo.js';
+
+foo();

test/test.js

@@ -426,7 +426,7 @@ describe( 'rollup', function () {
 	});
 
 	describe.only('incremental', function () {
-		it('uses previous bundle object to prevent unnecessary transformations', function () {
+		it('does not transforms in the second time', function () {
 			var calls = 0;
 			var counter = {
 				transform: function ( code ) {
@@ -435,12 +435,12 @@ describe( 'rollup', function () {
 				}
 			};
 			return rollup.rollup({
-				entry: path.join( INCREMENTAL, 'main.js' ),
+				entry: path.join( INCREMENTAL, 'not-transform-twice', 'main.js' ),
 				plugins: [counter]
 			}).then( function ( bundle ) {
 				assert.equal( calls, 2 );
 				return rollup.rollup({
-					entry: path.join( INCREMENTAL, 'main.js' ),
+					entry: path.join( INCREMENTAL, 'not-transform-twice', 'main.js' ),
 					plugins: [counter],
 					bundle
 				});
@@ -449,10 +449,54 @@ describe( 'rollup', function () {
 				var result = bundle.generate({
 					format: 'es6'
 				});
-				return sander.readFile( path.join( INCREMENTAL, 'expected.js' ) ).then( function (expected) {
-					assert.equal(expected.toString().replace( /(\r\n)/g, '\n'), result.code);
+				return sander.readFile( path.join( INCREMENTAL, 'not-transform-twice', 'expected.js' ) ).then( function (expected) {
+					assert.equal( normaliseOutput( expected ), result.code );
 				});
 			});
 		});
+
+		it('transforms modified sources', function () {
+			var calls = 0;
+			var counter = {
+				transform: function ( code ) {
+					calls += 1;
+					return code;
+				}
+			};
+			var bundle;
+			var foo;
+			var changed;
+			var expected;
+			return Promise.all([
+				rollup.rollup({
+					entry: path.join( INCREMENTAL, 'transform-changed', 'main.js' ),
+					plugins: [counter]
+				}),
+				sander.readFile( path.join( INCREMENTAL, 'transform-changed', 'foo.js' ) ),
+				sander.readFile( path.join( INCREMENTAL, 'transform-changed', 'foo-changed.js' ) ),
+				sander.readFile( path.join( INCREMENTAL, 'transform-changed', 'expected.js' ) )
+			]).then( function ( [_bundle, _foo, _changed, _expected] ) {
+				bundle = _bundle;
+				foo = normaliseOutput( _foo );
+				changed = normaliseOutput( _changed );
+				expected = normaliseOutput( _expected );
+				assert.equal( calls, 2 );
+
+				return sander.writeFile( INCREMENTAL, 'transform-changed', 'foo.js', changed );
+			}).then(function () {
+				return rollup.rollup({
+					entry: path.join( INCREMENTAL, 'transform-changed', 'main.js' ),
+					plugins: [counter],
+					bundle
+				});
+			}).then( function ( bundle ) {
+				assert.equal( calls, 3 );
+				var result = bundle.generate({
+					format: 'es6'
+				});
+				assert.equal(expected, result.code);
+				return sander.writeFile( INCREMENTAL, 'transform-changed', 'foo.js', foo );
+			});
+		});
 	});
 });