feat: support external star exports on namespace objects

src/Module.ts

@@ -5,7 +5,7 @@ import extractAssignedNames from 'rollup-pluginutils/src/extractAssignedNames';
 import {
 	createHasEffectsContext,
 	createInclusionContext,
-	InclusionContext
+	InclusionContext,
 } from './ast/ExecutionContext';
 import ExportAllDeclaration from './ast/nodes/ExportAllDeclaration';
 import ExportDefaultDeclaration from './ast/nodes/ExportDefaultDeclaration';
@@ -42,7 +42,7 @@ import {
 	ResolvedIdMap,
 	RollupError,
 	RollupWarning,
-	TransformModuleJSON
+	TransformModuleJSON,
 } from './rollup/types';
 import { error, Errors } from './utils/error';
 import getCodeFrame from './utils/getCodeFrame';
@@ -101,6 +101,7 @@ export interface AstContext {
 	getReexports: () => string[];
 	importDescriptions: { [name: string]: ImportDescription };
 	includeDynamicImport: (node: ImportExpression) => void;
+	includeExternalReexportNamespace: (name: string) => ExternalVariable;
 	includeVariable: (context: InclusionContext, variable: Variable) => void;
 	isCrossChunkImport: (importDescription: ImportDescription) => boolean;
 	magicString: MagicString;
@@ -122,7 +123,7 @@ export interface AstContext {
 export const defaultAcornOptions: acorn.Options = {
 	ecmaVersion: 2020,
 	preserveParens: false,
-	sourceType: 'module'
+	sourceType: 'module',
 };
 
 function tryParse(module: Module, Parser: typeof acorn.Parser, acornOptions: acorn.Options) {
@@ -131,7 +132,7 @@ function tryParse(module: Module, Parser: typeof acorn.Parser, acornOptions: aco
 			...defaultAcornOptions,
 			...acornOptions,
 			onComment: (block: boolean, text: string, start: number, end: number) =>
-				module.comments.push({ block, text, start, end })
+				module.comments.push({ block, text, start, end }),
 		});
 	} catch (err) {
 		let message = err.message.replace(/ \(\d+:\d+\)$/, '');
@@ -144,7 +145,7 @@ function tryParse(module: Module, Parser: typeof acorn.Parser, acornOptions: aco
 			{
 				code: 'PARSE_ERROR',
 				message,
-				parserError: err
+				parserError: err,
 			},
 			err.pos
 		);
@@ -163,15 +164,15 @@ function handleMissingExport(
 			message: `'${exportName}' is not exported by ${relativeId(
 				importedModule
 			)}, imported by ${relativeId(importingModule.id)}`,
-			url: `https://rollupjs.org/guide/en/#error-name-is-not-exported-by-module`
+			url: `https://rollupjs.org/guide/en/#error-name-is-not-exported-by-module`,
 		},
 		importerStart!
 	);
 }
 
 const MISSING_EXPORT_SHIM_DESCRIPTION: ExportDescription = {
 	identifier: null,
-	localName: MISSING_EXPORT_SHIM_VARIABLE
+	localName: MISSING_EXPORT_SHIM_VARIABLE,
 };
 
 function getVariableForExportNameRecursive(
@@ -288,17 +289,17 @@ export default class Module {
 					loc: {
 						column: location.column,
 						file: this.id,
-						line: location.line
+						line: location.line,
 					},
 					message: `Error when using sourcemap for reporting an error: ${e.message}`,
-					pos
+					pos,
 				});
 			}
 
 			props.loc = {
 				column: location.column,
 				file: this.id,
-				line: location.line
+				line: location.line,
 			};
 			props.frame = getCodeFrame(this.originalCode, location.line, location.column);
 		}
@@ -340,7 +341,7 @@ export default class Module {
 			return error({
 				code: Errors.SYNTHETIC_NAMED_EXPORTS_NEED_DEFAULT,
 				id: this.id,
-				message: `Modules with 'syntheticNamedExports' need a default export.`
+				message: `Modules with 'syntheticNamedExports' need a default export.`,
 			});
 		}
 		return this.defaultExport;
@@ -629,7 +630,7 @@ export default class Module {
 		sourcemapChain,
 		syntheticNamedExports,
 		transformDependencies,
-		transformFiles
+		transformFiles,
 	}: TransformModuleJSON & {
 		transformFiles?: EmittedFile[] | undefined;
 	}) {
@@ -664,7 +665,7 @@ export default class Module {
 
 		this.magicString = new MagicString(code, {
 			filename: (this.excludeFromSourcemap ? null : fileName)!, // don't include plugin helpers in sourcemap
-			indentExclusionRanges: []
+			indentExclusionRanges: [],
 		});
 		this.removeExistingSourceMap();
 
@@ -686,8 +687,9 @@ export default class Module {
 			getReexports: this.getReexports.bind(this),
 			importDescriptions: this.importDescriptions,
 			includeDynamicImport: this.includeDynamicImport.bind(this),
+			includeExternalReexportNamespace: this.includeExternalReexportNamespace.bind(this),
 			includeVariable: this.includeVariable.bind(this),
-			isCrossChunkImport: importDescription =>
+			isCrossChunkImport: (importDescription) =>
 				(importDescription.module as Module).chunk !== this.chunk,
 			magicString: this.magicString,
 			module: this,
@@ -705,7 +707,7 @@ export default class Module {
 				this.graph.treeshakingOptions.unknownGlobalSideEffects)!,
 			usesTopLevelAwait: false,
 			warn: this.warn.bind(this),
-			warnDeprecation: this.graph.warnDeprecation.bind(this.graph)
+			warnDeprecation: this.graph.warnDeprecation.bind(this.graph),
 		};
 
 		this.scope = new ModuleScope(this.graph.scope, this.astContext);
@@ -723,7 +725,7 @@ export default class Module {
 			ast: this.esTreeAst,
 			code: this.code,
 			customTransformCache: this.customTransformCache,
-			dependencies: Array.from(this.dependencies).map(module => module.id),
+			dependencies: Array.from(this.dependencies).map((module) => module.id),
 			id: this.id,
 			moduleSideEffects: this.moduleSideEffects,
 			originalCode: this.originalCode,
@@ -732,7 +734,7 @@ export default class Module {
 			sourcemapChain: this.sourcemapChain,
 			syntheticNamedExports: this.syntheticNamedExports,
 			transformDependencies: this.transformDependencies,
-			transformFiles: this.transformFiles
+			transformFiles: this.transformFiles,
 		};
 	}
 
@@ -793,7 +795,7 @@ export default class Module {
 
 			this.exports.default = {
 				identifier: node.variable.getAssignedVariableName(),
-				localName: 'default'
+				localName: 'default',
 			};
 		} else if (node instanceof ExportAllDeclaration) {
 			// export * from './other'
@@ -813,7 +815,7 @@ export default class Module {
 						specifier.type === NodeType.ExportNamespaceSpecifier ? '*' : specifier.local.name,
 					module: null as any, // filled in later,
 					source,
-					start: specifier.start
+					start: specifier.start,
 				};
 			}
 		} else if (node.declaration) {
@@ -854,7 +856,7 @@ export default class Module {
 				return this.error(
 					{
 						code: 'DUPLICATE_IMPORT',
-						message: `Duplicated import '${localName}'`
+						message: `Duplicated import '${localName}'`,
 					},
 					specifier.start
 				);
@@ -872,7 +874,7 @@ export default class Module {
 				module: null as any, // filled in later
 				name,
 				source,
-				start: specifier.start
+				start: specifier.start,
 			};
 		}
 	}
@@ -892,7 +894,9 @@ export default class Module {
 	}
 
 	private includeDynamicImport(node: ImportExpression) {
-		const resolution = (this.dynamicImports.find(dynamicImport => dynamicImport.node === node) as {
+		const resolution = (this.dynamicImports.find(
+			(dynamicImport) => dynamicImport.node === node
+		) as {
 			resolution: string | Module | ExternalModule | undefined;
 		}).resolution;
 		if (resolution instanceof Module) {
@@ -901,6 +905,20 @@ export default class Module {
 		}
 	}
 
+	private includeExternalReexportNamespace(name: string): ExternalVariable {
+		for (const module of this.exportAllModules) {
+			if (module instanceof ExternalModule) {
+				if (module.id === name) {
+					const externalVariable = module.getVariableForExportName('*');
+					externalVariable.include();
+					this.imports.add(externalVariable);
+					return externalVariable;
+				}
+			}
+		}
+		throw new Error(`Unable to find star reexport ExternalModule instance for ${name}`);
+	}
+
 	private includeVariable(context: InclusionContext, variable: Variable) {
 		const variableModule = variable.module;
 		if (!variable.included) {
@@ -926,7 +944,7 @@ export default class Module {
 				code: 'SHIMMED_EXPORT',
 				exporter: relativeId(this.id),
 				exportName: name,
-				message: `Missing export "${name}" has been shimmed in module ${relativeId(this.id)}.`
+				message: `Missing export "${name}" has been shimmed in module ${relativeId(this.id)}.`,
 			});
 			this.exports[name] = MISSING_EXPORT_SHIM_DESCRIPTION;
 		}

src/ast/variables/NamespaceVariable.ts

@@ -4,15 +4,17 @@ import { RESERVED_NAMES } from '../../utils/reservedNames';
 import { InclusionContext } from '../ExecutionContext';
 import Identifier from '../nodes/Identifier';
 import { UNKNOWN_PATH } from '../utils/PathTracker';
+import ExternalVariable from './ExternalVariable';
 import Variable from './Variable';
 
 export default class NamespaceVariable extends Variable {
 	context: AstContext;
 	isNamespace!: true;
 	memberVariables: { [name: string]: Variable } = Object.create(null);
 	module: Module;
+	reexportedNamespaces: string[] = [];
+	private reexportedNamespaceVariables: ExternalVariable[] = [];
 
-	private containsExternalNamespace = false;
 	private referencedEarly = false;
 	private references: Identifier[] = [];
 	private syntheticNamedExports: boolean;
@@ -41,20 +43,16 @@ export default class NamespaceVariable extends Variable {
 
 	include(context: InclusionContext) {
 		if (!this.included) {
-			if (this.containsExternalNamespace) {
-				return this.context.error({
-					code: 'NAMESPACE_CANNOT_CONTAIN_EXTERNAL',
-					id: this.module.id,
-					message: `Cannot create an explicit namespace object for module "${this.context.getModuleName()}" because it contains a reexported external namespace`
-				});
-			}
 			this.included = true;
 			for (const identifier of this.references) {
 				if (identifier.context.getModuleExecIndex() <= this.context.getModuleExecIndex()) {
 					this.referencedEarly = true;
 					break;
 				}
 			}
+			for (const name of this.reexportedNamespaces) {
+				this.reexportedNamespaceVariables.push(this.context.includeExternalReexportNamespace(name));
+			}
 			if (this.context.preserveModules) {
 				for (const memberName of Object.keys(this.memberVariables))
 					this.memberVariables[memberName].include(context);
@@ -67,8 +65,11 @@ export default class NamespaceVariable extends Variable {
 
 	initialise() {
 		for (const name of this.context.getExports().concat(this.context.getReexports())) {
-			if (name[0] === '*' && name.length > 1) this.containsExternalNamespace = true;
-			this.memberVariables[name] = this.context.traceExport(name);
+			if (name[0] === '*' && name.length > 1) {
+				this.reexportedNamespaces.push(name.slice(1));
+			} else {
+				this.memberVariables[name] = this.context.traceExport(name);
+			}
 		}
 	}
 
@@ -77,7 +78,7 @@ export default class NamespaceVariable extends Variable {
 		const n = options.compact ? '' : '\n';
 		const t = options.indent;
 
-		const members = Object.keys(this.memberVariables).map(name => {
+		const members = Object.keys(this.memberVariables).map((name) => {
 			const original = this.memberVariables[name];
 
 			if (this.referencedEarly || original.isReassigned) {
@@ -99,6 +100,11 @@ export default class NamespaceVariable extends Variable {
 
 		const name = this.getName();
 		let output = `{${n}${members.join(`,${n}`)}${n}}`;
+		if (this.reexportedNamespaceVariables.length) {
+			output = `/*#__PURE__*/Object.assign(${this.reexportedNamespaceVariables
+				.map((v) => v.getName())
+				.join(', ')}, ${output})`;
+		}
 		if (this.syntheticNamedExports) {
 			output = `/*#__PURE__*/Object.assign(${output}, ${this.module.getDefaultExport().getName()})`;
 		}

test/function/samples/internal-reexports-from-external/_config.js

@@ -1,16 +1,13 @@
-const path = require('path');
+const assert = require('assert');
+const fs = require('fs');
 
 module.exports = {
 	description:
 		'fails with a helpful error if creating a namespace object containing a reexported external namespace',
 	options: {
-		external: ['external']
+		external: ['fs'],
+	},
+	exports(ns) {
+		assert.strictEqual(ns.namespace.readFile, fs.readFile);
 	},
-	error: {
-		code: 'NAMESPACE_CANNOT_CONTAIN_EXTERNAL',
-		message:
-			'Cannot create an explicit namespace object for module "reexport" because it contains a reexported external namespace',
-		id: path.join(__dirname, 'reexport.js'),
-		watchFiles: [path.join(__dirname, 'main.js'), path.join(__dirname, 'reexport.js')]
-	}
 };

test/function/samples/internal-reexports-from-external/main.js

@@ -1,3 +1,3 @@
 import * as namespace from './reexport.js';
 
-console.log(namespace);
+export { namespace };

test/function/samples/internal-reexports-from-external/reexport.js

@@ -1 +1 @@
-export * from 'external';
+export * from 'fs';