Make sure default exports snapshot synthetic named exports (#3946)

src/Module.ts

@@ -199,7 +199,7 @@ function getAndExtendSideEffectModules(variable: Variable, module: Module): Set<
 		if (!currentVariable || referencedVariables.has(currentVariable)) {
 			break;
 		}
-		referencedVariables.add(variable);
+		referencedVariables.add(currentVariable);
 		sideEffectModules.add(importingModule);
 		const originalSideEffects = importingModule.sideEffectDependenciesByVariable.get(
 			currentVariable

src/ast/variables/ExportDefaultVariable.ts

@@ -55,7 +55,9 @@ export default class ExportDefaultVariable extends LocalVariable {
 			(this.hasId ||
 				!(
 					this.originalId.variable.isReassigned ||
-					this.originalId.variable instanceof UndefinedVariable
+					this.originalId.variable instanceof UndefinedVariable ||
+					// this avoids a circular dependency
+					'syntheticNamespace' in this.originalId.variable
 				))
 			? this.originalId.variable
 			: null;

src/ast/variables/SyntheticNamedExportVariable.ts

@@ -1,5 +1,4 @@
 import Module, { AstContext } from '../../Module';
-import { error, errSyntheticNamedExportsNeedNamespaceExport } from '../../utils/error';
 import { RESERVED_NAMES } from '../../utils/reservedNames';
 import ExportDefaultVariable from './ExportDefaultVariable';
 import Variable from './Variable';
@@ -21,12 +20,10 @@ export default class SyntheticNamedExportVariable extends Variable {
 	getBaseVariable(): Variable {
 		if (this.baseVariable) return this.baseVariable;
 		let baseVariable = this.syntheticNamespace;
-		const checkedVariables = new Set<Variable>();
 		while (
 			baseVariable instanceof ExportDefaultVariable ||
 			baseVariable instanceof SyntheticNamedExportVariable
 		) {
-			checkedVariables.add(baseVariable);
 			if (baseVariable instanceof ExportDefaultVariable) {
 				const original = baseVariable.getOriginalVariable();
 				if (original === baseVariable) break;
@@ -35,14 +32,6 @@ export default class SyntheticNamedExportVariable extends Variable {
 			if (baseVariable instanceof SyntheticNamedExportVariable) {
 				baseVariable = baseVariable.syntheticNamespace;
 			}
-			if (checkedVariables.has(baseVariable)) {
-				return error(
-					errSyntheticNamedExportsNeedNamespaceExport(
-						this.module.id,
-						this.module.info.syntheticNamedExports
-					)
-				);
-			}
 		}
 		return (this.baseVariable = baseVariable);
 	}

test/chunking-form/samples/synthetic-named-exports/chained-default-reexport/lib-reexport.js

@@ -1,3 +1,3 @@
 import { named } from './lib-reexport2.js';
 console.log('side-effect', named);
-export default named;
+export { named as default };

test/chunking-form/samples/synthetic-named-exports/chained-default-reexport/lib-reexport2.js

@@ -1,3 +1,3 @@
 import { named } from './lib.js';
 console.log('side-effect', named);
-export default named;
+export { named as default };

test/function/samples/synthetic-named-exports/circular-synthetic-exports/_config.js

@@ -12,9 +12,10 @@ module.exports = {
 			}
 		]
 	},
-	generateError: {
+	error: {
 		code: 'SYNTHETIC_NAMED_EXPORTS_NEED_NAMESPACE_EXPORT',
 		id: path.join(__dirname, 'main.js'),
-		message: `Module "main.js" that is marked with 'syntheticNamedExports: "__synthetic"' needs an export named "__synthetic" that does not reexport an unresolved named export of the same module.`
+		message: `Module "main.js" that is marked with 'syntheticNamedExports: "__synthetic"' needs an export named "__synthetic" that does not reexport an unresolved named export of the same module.`,
+		watchFiles: [path.join(__dirname, 'main.js'), path.join(__dirname, 'dep.js')]
 	}
 };

test/function/samples/synthetic-named-exports/circular-synthetic-exports/dep.js

@@ -1,2 +1 @@
-import { foo } from './main.js';
-export default foo;
+export { foo as default } from './main.js';

test/function/samples/synthetic-named-exports/circular-synthetic-exports2/_config.js

@@ -0,0 +1,11 @@
+module.exports = {
+	description: 'handles circular synthetic exports',
+	warnings: [
+		{
+			code: 'CIRCULAR_DEPENDENCY',
+			cycle: ['dep1.js', 'dep2.js', 'dep1.js'],
+			importer: 'dep1.js',
+			message: 'Circular dependency: dep1.js -> dep2.js -> dep1.js'
+		}
+	]
+};

test/function/samples/synthetic-named-exports/circular-synthetic-exports2/dep1.js

@@ -0,0 +1,2 @@
+import dep2 from './dep2';
+export default dep2;

test/function/samples/synthetic-named-exports/circular-synthetic-exports2/dep2.js

@@ -0,0 +1,2 @@
+import dep1 from './dep1';
+export default dep1;

test/function/samples/synthetic-named-exports/circular-synthetic-exports2/main.js

@@ -0,0 +1,2 @@
+import dep1 from './dep1';
+assert.strictEqual(dep1, undefined);

test/function/samples/synthetic-named-exports/synthetic-named-export-as-default/_config.js

@@ -0,0 +1,10 @@
+module.exports = {
+	description: 'makes sure default exports of synthetic named exports are snapshots',
+	options: {
+		plugins: {
+			transform() {
+				return { syntheticNamedExports: '__synthetic' };
+			}
+		}
+	}
+};

test/function/samples/synthetic-named-exports/synthetic-named-export-as-default/dep.js

@@ -0,0 +1,2 @@
+import { foo } from './synthetic';
+export default foo;

test/function/samples/synthetic-named-exports/synthetic-named-export-as-default/main.js

@@ -0,0 +1,6 @@
+import foo from './dep';
+import { update } from './synthetic';
+
+assert.strictEqual(foo, 'original');
+update();
+assert.strictEqual(foo, 'original');

test/function/samples/synthetic-named-exports/synthetic-named-export-as-default/synthetic.js

@@ -0,0 +1,2 @@
+export const __synthetic = { foo: 'original' };
+export const update = () => (__synthetic.foo = 'reassigned');