improve final loader not string/buffer message

sokra · sokra · commit 1886ee0f3fcf · 2018-06-05T11:58:10.000+02:00
add test case
diff --git a/lib/NormalModule.js b/lib/NormalModule.js
@@ -230,13 +230,15 @@ class NormalModule extends Module {
 		return loaderContext;
 	}
 
-	getCurrentLoader(loaderContext) {
+	getCurrentLoader(loaderContext, index = loaderContext.loaderIndex) {
 		if (
 			this.loaders &&
 			this.loaders.length &&
-			this.loaders[loaderContext.loaderIndex]
+			index < this.loaders.length &&
+			index >= 0 &&
+			this.loaders[index]
 		) {
-			return this.loaders[loaderContext.loaderIndex];
+			return this.loaders[index];
 		}
 		return null;
 	}
@@ -296,9 +298,11 @@ class NormalModule extends Module {
 				if (err) {
 					const currentLoader = this.getCurrentLoader(loaderContext);
 					const error = new ModuleBuildError(this, err, {
-						from: compilation.runtimeTemplate.requestShortener.shorten(
-							currentLoader.loader
-						)
+						from:
+							currentLoader &&
+							compilation.runtimeTemplate.requestShortener.shorten(
+								currentLoader.loader
+							)
 					});
 					return callback(error);
 				}
@@ -309,10 +313,17 @@ class NormalModule extends Module {
 				const extraInfo = result.result.length >= 2 ? result.result[2] : null;
 
 				if (!Buffer.isBuffer(source) && typeof source !== "string") {
-					const error = new ModuleBuildError(
-						this,
-						new Error("Final loader didn't return a Buffer or String")
+					const currentLoader = this.getCurrentLoader(loaderContext, 0);
+					const err = new Error(
+						`Final loader (${
+							currentLoader
+								? compilation.runtimeTemplate.requestShortener.shorten(
+										currentLoader.loader
+								  )
+								: "unknown"
+						}) didn't return a Buffer or String`
 					);
+					const error = new ModuleBuildError(this, err);
 					return callback(error);
 				}
 
diff --git a/test/cases/loaders/no-string/errors.js b/test/cases/loaders/no-string/errors.js
@@ -0,0 +1,10 @@
+module.exports = [
+	[
+		/\.\/loaders\/no-string\/file\.js \(\.\/loaders\/no-string\/loader\.js!\.\/loaders\/no-string\/file\.js\)/,
+		/Module build failed: Error: Final loader \(\.\/loaders\/no-string\/loader\.js\) didn't return a Buffer or String/
+	],
+	[
+		/\.\/loaders\/no-string\/file\.js \(\.\/loaders\/no-string\/loader\.js!\.\/loaders\/no-string\/pitch-loader\.js!\.\/loaders\/no-string\/file\.js\)/,
+		/Module build failed: Error: Final loader \(\.\/loaders\/no-string\/loader\.js\) didn't return a Buffer or String/
+	]
+];
diff --git a/test/cases/loaders/no-string/file.js b/test/cases/loaders/no-string/file.js
@@ -0,0 +1 @@
+123
diff --git a/test/cases/loaders/no-string/index.js b/test/cases/loaders/no-string/index.js
@@ -0,0 +1,8 @@
+it("should emit the correct error for loaders not returning buffer or string", function() {
+	expect(() => require("./loader.js!./file.js")).toThrowError(
+		/Module build failed/
+	);
+	expect(() => require("./loader.js!./pitch-loader.js!./file.js")).toThrowError(
+		/Module build failed/
+	);
+});
diff --git a/test/cases/loaders/no-string/loader.js b/test/cases/loaders/no-string/loader.js
@@ -0,0 +1,3 @@
+module.exports = () => {
+	return 123;
+};
diff --git a/test/cases/loaders/no-string/pitch-loader.js b/test/cases/loaders/no-string/pitch-loader.js
@@ -0,0 +1,3 @@
+module.exports = () => {
+	return 123;
+};

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+module.exports = () => {`
	`2`	`+ return 123;`
	`3`	`+};`