webpack · alexander-akait · May 20, 2025 · May 16, 2025
diff --git a/lib/asset/AssetGenerator.js b/lib/asset/AssetGenerator.js
@@ -657,6 +657,7 @@ class AssetGenerator extends Generator {
 	 * @returns {SourceTypes} available types (do not mutate)
 	 */
 	getTypes(module) {
+		/** @type {Set<string>} */
 		const sourceTypes = new Set();
 		const connections = this._moduleGraph.getIncomingConnections(module);
 
@@ -669,27 +670,25 @@ class AssetGenerator extends Generator {
 		}
 
 		if ((module.buildInfo && module.buildInfo.dataUrl) || this.emit === false) {
-			if (sourceTypes) {
+			if (sourceTypes.size > 0) {
 				if (sourceTypes.has("javascript") && sourceTypes.has("css")) {
 					return JS_AND_CSS_URL_TYPES;
-				} else if (sourceTypes.has("javascript")) {
-					return JS_TYPES;
 				} else if (sourceTypes.has("css")) {
 					return CSS_URL_TYPES;
 				}
+				return JS_TYPES;
 			}
 
 			return NO_TYPES;
 		}
 
-		if (sourceTypes) {
+		if (sourceTypes.size > 0) {
 			if (sourceTypes.has("javascript") && sourceTypes.has("css")) {
 				return ASSET_AND_JS_AND_CSS_URL_TYPES;
-			} else if (sourceTypes.has("javascript")) {
-				return ASSET_AND_JS_TYPES;
 			} else if (sourceTypes.has("css")) {
 				return ASSET_AND_CSS_URL_TYPES;
 			}
+			return ASSET_AND_JS_TYPES;
 		}
 
 		return ASSET_TYPES;

diff --git a/lib/asset/AssetSourceGenerator.js b/lib/asset/AssetSourceGenerator.js
@@ -122,6 +122,7 @@ class AssetSourceGenerator extends Generator {
 	 * @returns {SourceTypes} available types (do not mutate)
 	 */
 	getTypes(module) {
+		/** @type {Set<string>} */
 		const sourceTypes = new Set();
 		const connections = this._moduleGraph.getIncomingConnections(module);
 
@@ -133,12 +134,13 @@ class AssetSourceGenerator extends Generator {
 			sourceTypes.add(connection.originModule.type.split("/")[0]);
 		}
 
-		if (sourceTypes.has("javascript") && sourceTypes.has("css")) {
-			return JS_AND_CSS_URL_TYPES;
-		} else if (sourceTypes.has("javascript")) {
+		if (sourceTypes.size > 0) {
+			if (sourceTypes.has("javascript") && sourceTypes.has("css")) {
+				return JS_AND_CSS_URL_TYPES;
+			} else if (sourceTypes.has("css")) {
+				return CSS_URL_TYPES;
+			}
 			return JS_TYPES;
-		} else if (sourceTypes.has("css")) {
-			return CSS_URL_TYPES;
 		}
 
 		return NO_TYPES;

diff --git a/test/hotCases/asset-modules-source/lazy-compilation/file.text b/test/hotCases/asset-modules-source/lazy-compilation/file.text
@@ -0,0 +1,6 @@
+We use `NEXT()` to trigger one compilation to simulate lazy compilation behavior.
+So this initial content will be ignored.
+---
+A
+---
+B
diff --git a/test/hotCases/asset-modules-source/lazy-compilation/index.js b/test/hotCases/asset-modules-source/lazy-compilation/index.js
@@ -0,0 +1,21 @@
+const getFile = name =>
+	__non_webpack_require__("fs").readFileSync(
+		__non_webpack_require__("path").join(__dirname, name),
+		"utf-8"
+	);
+
+it("should work", async function (done) {
+	let promise = import("./file.text");
+	NEXT(
+		require("../../update")(done, true, () => {
+			promise.then(() => {
+				expect(getFile("./assets/file.text")).toContain("A");
+				module.hot.accept("./file.text", () => {
+					expect(getFile("./assets/file.text")).toContain("B");
+					done();
+				});
+				NEXT(require("../../update")(done));
+			});
+		})
+	);
+});
diff --git a/test/hotCases/asset-modules-source/lazy-compilation/webpack.config.js b/test/hotCases/asset-modules-source/lazy-compilation/webpack.config.js
@@ -0,0 +1,25 @@
+/** @type {import("../../../../").Configuration} */
+module.exports = {
+	experiments: {
+		lazyCompilation: {
+			entries: false,
+			imports: true
+		}
+	},
+	node: {
+		__dirname: false
+	},
+	module: {
+		generator: {
+			asset: {
+				filename: "assets/[name][ext]"
+			}
+		},
+		rules: [
+			{
+				test: /file\.text$/,
+				type: "asset/resource"
+			}
+		]
+	}
+};