Provide synthetic namespace for dynamic imports when perserving modul…

…es (#4913)

src/Chunk.ts

@@ -216,7 +216,7 @@ export default class Chunk {
 
 		for (const module of orderedModules) {
 			chunkByModule.set(module, this);
-			if (module.namespace.included) {
+			if (module.namespace.included && !outputOptions.preserveModules) {
 				includedNamespaces.add(module);
 			}
 			if (this.isEmpty && module.isIncluded()) {
@@ -229,7 +229,7 @@ export default class Chunk {
 				if (!chunkModules.has(importer)) {
 					this.dynamicEntryModules.push(module);
 					// Modules with synthetic exports need an artificial namespace for dynamic imports
-					if (module.info.syntheticNamedExports && !outputOptions.preserveModules) {
+					if (module.info.syntheticNamedExports) {
 						includedNamespaces.add(module);
 						this.exports.add(module.namespace);
 					}
@@ -407,14 +407,11 @@ export default class Chunk {
 			}
 			if (!this.facadeModule) {
 				const needsStrictFacade =
-					module.preserveSignature === 'strict' ||
-					(module.preserveSignature === 'exports-only' &&
-						module.getExportNamesByVariable().size > 0);
-				if (
-					!needsStrictFacade ||
-					this.outputOptions.preserveModules ||
-					this.canModuleBeFacade(module, exposedVariables)
-				) {
+					!this.outputOptions.preserveModules &&
+					(module.preserveSignature === 'strict' ||
+						(module.preserveSignature === 'exports-only' &&
+							module.getExportNamesByVariable().size > 0));
+				if (!needsStrictFacade || this.canModuleBeFacade(module, exposedVariables)) {
 					this.facadeModule = module;
 					this.facadeChunkByModule.set(module, this);
 					if (module.preserveSignature) {
@@ -1140,14 +1137,7 @@ export default class Chunk {
 			renderedModules,
 			snippets
 		} = this;
-		const {
-			compact,
-			dynamicImportFunction,
-			format,
-			freeze,
-			namespaceToStringTag,
-			preserveModules
-		} = outputOptions;
+		const { compact, dynamicImportFunction, format, freeze, namespaceToStringTag } = outputOptions;
 		const { _, cnst, n } = snippets;
 		this.setDynamicImportResolutions(fileName);
 		this.setImportMetaResolutions(fileName);
@@ -1188,7 +1178,7 @@ export default class Chunk {
 					usedModules.push(module);
 				}
 				const namespace = module.namespace;
-				if (includedNamespaces.has(module) && !preserveModules) {
+				if (includedNamespaces.has(module)) {
 					const rendered = namespace.renderBlock(renderOptions);
 					if (namespace.renderFirst()) hoistedSource += n + rendered;
 					else magicString.addSource(new MagicString(rendered));
@@ -1346,13 +1336,13 @@ export default class Chunk {
 			accessedGlobalsByScope,
 			includedNamespaces,
 			orderedModules,
-			outputOptions: { format, preserveModules }
+			outputOptions: { format }
 		} = this;
 		for (const module of orderedModules) {
 			for (const importMeta of module.importMetas) {
 				importMeta.setResolution(format, accessedGlobalsByScope, fileName);
 			}
-			if (includedNamespaces.has(module) && !preserveModules) {
+			if (includedNamespaces.has(module)) {
 				module.namespace.prepare(accessedGlobalsByScope);
 			}
 		}

test/chunking-form/samples/dynamic-import-synthetic-exports-preserve-modules/_config.js

@@ -12,6 +12,7 @@ module.exports = {
 			}
 		},
 		output: {
+			exports: 'named',
 			preserveModules: true
 		}
 	}

test/chunking-form/samples/dynamic-import-synthetic-exports-preserve-modules/_expected/amd/lib.js

@@ -1,8 +1,31 @@
-define((function () { 'use strict';
+define(['exports'], (function (exports) { 'use strict';
+
+	function _mergeNamespaces(n, m) {
+		m.forEach(function (e) {
+			e && typeof e !== 'string' && !Array.isArray(e) && Object.keys(e).forEach(function (k) {
+				if (k !== 'default' && !(k in n)) {
+					var d = Object.getOwnPropertyDescriptor(e, k);
+					Object.defineProperty(n, k, d.get ? d : {
+						enumerable: true,
+						get: function () { return e[k]; }
+					});
+				}
+			});
+		});
+		return Object.freeze(n);
+	}
 
 	const __moduleExports = { foo: 'bar' };
 	var lib = 'baz';
 
-	return lib;
+	var lib$1 = /*#__PURE__*/_mergeNamespaces({
+		__proto__: null,
+		default: lib
+	}, [__moduleExports]);
+
+	exports.default = lib;
+	exports.lib = lib$1;
+
+	Object.defineProperty(exports, '__esModule', { value: true });
 
 }));

test/chunking-form/samples/dynamic-import-synthetic-exports-preserve-modules/_expected/amd/main.js

@@ -1,7 +1,5 @@
 define(['require'], (function (require) { 'use strict';
 
-	function _interopNamespaceDefaultOnly (e) { return Object.freeze({ __proto__: null, default: e }); }
-
-	new Promise(function (resolve, reject) { require(['./lib'], function (m) { resolve(/*#__PURE__*/_interopNamespaceDefaultOnly(m)); }, reject); }).then(console.log);
+	new Promise(function (resolve, reject) { require(['./lib'], resolve, reject); }).then(function (n) { return n.lib; }).then(console.log);
 
 }));

test/chunking-form/samples/dynamic-import-synthetic-exports-preserve-modules/_expected/cjs/lib.js

@@ -1,6 +1,29 @@
 'use strict';
 
+Object.defineProperty(exports, '__esModule', { value: true });
+
+function _mergeNamespaces(n, m) {
+	m.forEach(function (e) {
+		e && typeof e !== 'string' && !Array.isArray(e) && Object.keys(e).forEach(function (k) {
+			if (k !== 'default' && !(k in n)) {
+				var d = Object.getOwnPropertyDescriptor(e, k);
+				Object.defineProperty(n, k, d.get ? d : {
+					enumerable: true,
+					get: function () { return e[k]; }
+				});
+			}
+		});
+	});
+	return Object.freeze(n);
+}
+
 const __moduleExports = { foo: 'bar' };
 var lib = 'baz';
 
-module.exports = lib;
+var lib$1 = /*#__PURE__*/_mergeNamespaces({
+	__proto__: null,
+	default: lib
+}, [__moduleExports]);
+
+exports.default = lib;
+exports.lib = lib$1;

test/chunking-form/samples/dynamic-import-synthetic-exports-preserve-modules/_expected/cjs/main.js

@@ -1,5 +1,3 @@
 'use strict';
 
-function _interopNamespaceDefaultOnly (e) { return Object.freeze({ __proto__: null, default: e }); }
-
-Promise.resolve().then(function () { return /*#__PURE__*/_interopNamespaceDefaultOnly(require('./lib.js')); }).then(console.log);
+Promise.resolve().then(function () { return require('./lib.js'); }).then(function (n) { return n.lib; }).then(console.log);

test/chunking-form/samples/dynamic-import-synthetic-exports-preserve-modules/_expected/es/lib.js

@@ -1,4 +1,24 @@
+function _mergeNamespaces(n, m) {
+	m.forEach(function (e) {
+		e && typeof e !== 'string' && !Array.isArray(e) && Object.keys(e).forEach(function (k) {
+			if (k !== 'default' && !(k in n)) {
+				var d = Object.getOwnPropertyDescriptor(e, k);
+				Object.defineProperty(n, k, d.get ? d : {
+					enumerable: true,
+					get: function () { return e[k]; }
+				});
+			}
+		});
+	});
+	return Object.freeze(n);
+}
+
 const __moduleExports = { foo: 'bar' };
 var lib = 'baz';
 
-export { lib as default };
+var lib$1 = /*#__PURE__*/_mergeNamespaces({
+	__proto__: null,
+	default: lib
+}, [__moduleExports]);
+
+export { lib as default, lib$1 as l };

test/chunking-form/samples/dynamic-import-synthetic-exports-preserve-modules/_expected/es/main.js

@@ -1 +1 @@
-import('./lib.js').then(console.log);
+import('./lib.js').then(function (n) { return n.l; }).then(console.log);

test/chunking-form/samples/dynamic-import-synthetic-exports-preserve-modules/_expected/system/lib.js

@@ -3,9 +3,30 @@ System.register([], (function (exports) {
 	return {
 		execute: (function () {
 
+			function _mergeNamespaces(n, m) {
+				m.forEach(function (e) {
+					e && typeof e !== 'string' && !Array.isArray(e) && Object.keys(e).forEach(function (k) {
+						if (k !== 'default' && !(k in n)) {
+							var d = Object.getOwnPropertyDescriptor(e, k);
+							Object.defineProperty(n, k, d.get ? d : {
+								enumerable: true,
+								get: function () { return e[k]; }
+							});
+						}
+					});
+				});
+				return Object.freeze(n);
+			}
+
 			const __moduleExports = { foo: 'bar' };
 			var lib = exports('default', 'baz');
 
+			var lib$1 = /*#__PURE__*/_mergeNamespaces({
+				__proto__: null,
+				default: lib
+			}, [__moduleExports]);
+			exports('l', lib$1);
+
 		})
 	};
 }));

test/chunking-form/samples/dynamic-import-synthetic-exports-preserve-modules/_expected/system/main.js

@@ -3,7 +3,7 @@ System.register([], (function (exports, module) {
 	return {
 		execute: (function () {
 
-			module.import('./lib.js').then(console.log);
+			module.import('./lib.js').then(function (n) { return n.l; }).then(console.log);
 
 		})
 	};

test/function/samples/synthetic-named-exports/preserve-modules/_config.js

@@ -0,0 +1,24 @@
+const assert = require('node:assert');
+
+module.exports = {
+	description: 'handles a dynamic import with synthetic named exports in preserveModules mode',
+	options: {
+		output: {
+			preserveModules: true
+		},
+		plugins: [
+			{
+				name: 'test',
+				transform() {
+					return {
+						syntheticNamedExports: '__synthetic'
+					};
+				}
+			}
+		]
+	},
+	async exports(exports) {
+		const { foo } = await exports.promise;
+		assert.strictEqual(foo, 'bar');
+	}
+};

test/function/samples/synthetic-named-exports/preserve-modules/main.js

@@ -0,0 +1 @@
+export const promise = import('./other');

test/function/samples/synthetic-named-exports/preserve-modules/other.js

@@ -0,0 +1 @@
+export const __synthetic = { foo: 'bar' };