fix: handle default for import context element dependency

lib/dependencies/ContextElementDependency.js

@@ -11,6 +11,9 @@ const ModuleDependency = require("./ModuleDependency");
 
 /** @typedef {import("../Dependency").ReferencedExport} ReferencedExport */
 /** @typedef {import("../ModuleGraph")} ModuleGraph */
+/** @typedef {import("../Module")} Module */
+/** @typedef {import("../Module").BuildMeta} BuildMeta */
+/** @typedef {import("../ContextModule")} ContextModule */
 /** @typedef {import("../javascript/JavascriptParser").ImportAttributes} ImportAttributes */
 /** @typedef {import("../serialization/ObjectMiddleware").ObjectDeserializerContext} ObjectDeserializerContext */
 /** @typedef {import("../serialization/ObjectMiddleware").ObjectSerializerContext} ObjectSerializerContext */
@@ -67,12 +70,36 @@ class ContextElementDependency extends ModuleDependency {
 	 * @returns {(string[] | ReferencedExport)[]} referenced exports
 	 */
 	getReferencedExports(moduleGraph, runtime) {
-		return this.referencedExports
-			? this.referencedExports.map(e => ({
-					name: e,
-					canMangle: false
-				}))
-			: Dependency.EXPORTS_OBJECT_REFERENCED;
+		if (!this.referencedExports) return Dependency.EXPORTS_OBJECT_REFERENCED;
+		const refs = [];
+		for (const referencedExport of this.referencedExports) {
+			if (
+				this._typePrefix === "import()" &&
+				referencedExport[0] === "default"
+			) {
+				const selfModule =
+					/** @type {ContextModule} */
+					(moduleGraph.getParentModule(this));
+				const importedModule =
+					/** @type {Module} */
+					(moduleGraph.getModule(this));
+				const exportsType = importedModule.getExportsType(
+					moduleGraph,
+					selfModule.options.namespaceObject === "strict"
+				);
+				if (
+					exportsType === "default-only" ||
+					exportsType === "default-with-named"
+				) {
+					return Dependency.EXPORTS_OBJECT_REFERENCED;
+				}
+			}
+			refs.push({
+				name: referencedExport,
+				canMangle: false
+			});
+		}
+		return refs;
 	}
 
 	/**

test/cases/chunks/destructuring-assignment/dir3/a.js

@@ -0,0 +1,2 @@
+exports.a = 1;
+exports.b = 2;

test/cases/chunks/destructuring-assignment/dir3/json/array.json

@@ -0,0 +1 @@
+["a"]

test/cases/chunks/destructuring-assignment/dir3/json/object.json

@@ -0,0 +1 @@
+{"a": 1}

test/cases/chunks/destructuring-assignment/dir3/json/primitive.json

@@ -0,0 +1 @@
+"a"

test/cases/chunks/destructuring-assignment/index.js

@@ -21,3 +21,16 @@ it("should not tree-shake default export for exportsType=default module", async
 	const { default: a } = await import("./dir2/a");
 	expect(a).toEqual({ a: 1, b: 2 });
 });
+
+it("should not tree-shake default export for exportsType=default context module", async () => {
+	const dir = "json";
+	const { default: object } = await import(`./dir3/${dir}/object.json`);
+	const { default: array } = await import(`./dir3/${dir}/array.json`);
+	const { default: primitive } = await import(`./dir3/${dir}/primitive.json`);
+	expect(object).toEqual({ a: 1 });
+	expect(array).toEqual(["a"]);
+	expect(primitive).toBe("a");
+	const file = "a";
+	const { default: a } = await import(`./dir3/${file}`);
+	expect(a).toEqual({ a: 1, b: 2 });
+});

test/cases/chunks/inline-options/dir16/a.js

@@ -0,0 +1,2 @@
+exports.a = 1;
+exports.b = 2;

test/cases/chunks/inline-options/dir16/json/array.json

@@ -0,0 +1 @@
+["a"]

test/cases/chunks/inline-options/dir16/json/object.json

@@ -0,0 +1 @@
+{"a": 1}

test/cases/chunks/inline-options/dir16/json/primitive.json

@@ -0,0 +1 @@
+"a"

test/cases/chunks/inline-options/index.js

@@ -203,6 +203,23 @@ if (process.env.NODE_ENV === "production") {
 		expect(a.a).toBe(1);
 		expect(a.b).toBe(2);
 	})
+
+	it("should not tree-shake default export for exportsType=default context module", async function () {
+		const dir = "json";
+		const jsonObject = await import(/* webpackExports: ["default"] */ `./dir16/${dir}/object.json`);
+		const jsonArray = await import(/* webpackExports: ["default"] */ `./dir16/${dir}/array.json`);
+		const jsonPrimitive = await import(/* webpackExports: ["default"] */ `./dir16/${dir}/primitive.json`);
+		expect(jsonObject.default).toEqual({ a: 1 });
+		expect(jsonObject.a).toEqual(1);
+		expect(jsonArray.default).toEqual(["a"]);
+		expect(jsonArray[0]).toBe("a");
+		expect(jsonPrimitive.default).toBe("a");
+		const file = "a";
+		const a = await import(/* webpackExports: ["default"] */`./dir16/${file}`);
+		expect(a.default).toEqual({ a: 1, b: 2 });
+		expect(a.a).toBe(1);
+		expect(a.b).toBe(2);
+	})
 }
 
 function testChunkLoading(load, expectedSyncInitial, expectedSyncRequested) {