Merge pull request #4538 from webpack/feature/error-emit-warning

add stack to non-Error error emitted

lib/ErrorHelpers.js

@@ -0,0 +1,31 @@
+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+	Author Tobias Koppers @sokra
+*/
+"use strict";
+
+const loaderFlag = "LOADER_EXECUTION";
+
+exports.cutOffLoaderExecution = (stack) => {
+	stack = stack.split("\n");
+	for(let i = 0; i < stack.length; i++)
+		if(stack[i].indexOf(loaderFlag) >= 0)
+			stack.length = i;
+	return stack.join("\n");
+};
+
+exports.cutOffMessage = (stack, message) => {
+	const nextLine = stack.indexOf("\n");
+	if(nextLine === -1) {
+		return stack === message ? "" : stack;
+	} else {
+		const firstLine = stack.substr(0, nextLine);
+		return firstLine === message ? stack.substr(nextLine + 1) : stack;
+	}
+};
+
+exports.cleanUp = (stack, message) => {
+	stack = exports.cutOffLoaderExecution(stack);
+	stack = exports.cutOffMessage(stack, message);
+	return stack;
+};

lib/ModuleBuildError.js

@@ -4,7 +4,7 @@
 */
 "use strict";
 
-const loaderFlag = "LOADER_EXECUTION";
+const cutOffLoaderExecution = require("./ErrorHelpers").cutOffLoaderExecution;
 
 class ModuleBuildError extends Error {
 
@@ -14,11 +14,7 @@ class ModuleBuildError extends Error {
 		this.message = "Module build failed: ";
 		if(err !== null && typeof err === "object") {
 			if(typeof err.stack === "string" && err.stack) {
-				var stack = err.stack.split("\n");
-				for(var i = 0; i < stack.length; i++)
-					if(stack[i].indexOf(loaderFlag) >= 0)
-						stack.length = i;
-				stack = stack.join("\n");
+				var stack = cutOffLoaderExecution(err.stack);
 				if(!err.hideStack) {
 					this.message += stack;
 				} else {

lib/ModuleError.js

@@ -4,15 +4,18 @@
 */
 "use strict";
 
+const cleanUp = require("./ErrorHelpers").cleanUp;
+
 class ModuleError extends Error {
 
 	constructor(module, err) {
 		super();
 
 		this.name = "ModuleError";
 		this.module = module;
-		this.message = err;
+		this.message = err && typeof err === "object" && err.message ? err.message : err;
 		this.error = err;
+		this.details = err && typeof err === "object" && err.stack ? cleanUp(err.stack, this.message) : undefined;
 
 		Error.captureStackTrace(this, this.constructor);
 	}

lib/ModuleWarning.js

@@ -4,14 +4,18 @@
 */
 "use strict";
 
+const cleanUp = require("./ErrorHelpers").cleanUp;
+
 class ModuleWarning extends Error {
+
 	constructor(module, warning) {
 		super();
 
 		this.name = "ModuleWarning";
 		this.module = module;
-		this.message = warning;
+		this.message = warning && typeof warning === "object" && warning.message ? warning.message : warning;
 		this.warning = warning;
+		this.details = warning && typeof warning === "object" && warning.stack ? cleanUp(warning.stack, this.message) : undefined;
 
 		Error.captureStackTrace(this, this.constructor);
 	}

lib/NormalModule.js

@@ -42,6 +42,18 @@ function contextify(context, request) {
 	}).join("!");
 }
 
+class NonErrorEmittedError extends Error {
+
+	constructor(error) {
+		super();
+
+		this.name = "NonErrorEmittedError";
+		this.message = "(Emitted value instead of an instance of Error) " + error;
+
+		Error.captureStackTrace(this, this.constructor);
+	}
+}
+
 class NormalModule extends Module {
 
 	constructor(request, userRequest, rawRequest, loaders, resource, parser) {
@@ -98,9 +110,13 @@ class NormalModule extends Module {
 		const loaderContext = {
 			version: 2,
 			emitWarning: (warning) => {
+				if(!(warning instanceof Error))
+					warning = new NonErrorEmittedError(warning);
 				this.warnings.push(new ModuleWarning(this, warning));
 			},
 			emitError: (error) => {
+				if(!(error instanceof Error))
+					error = new NonErrorEmittedError(error);
 				this.errors.push(new ModuleError(this, error));
 			},
 			exec: (code, filename) => {

test/cases/errors/loader-error-warning/errors.js

@@ -1,4 +1,12 @@
 module.exports = [
-	[/abc/],
-	[/def/]
+	[
+		/abc/,
+		/Emitted value instead of an instance of Error/,
+		/error-loader\.js/
+	],
+	[
+		/def/,
+		/Emitted value instead of an instance of Error/,
+		/error-loader\.js/
+	]
 ];

test/cases/errors/loader-error-warning/warnings.js

@@ -1,3 +1,7 @@
 module.exports = [
-	[/xyz/]
+	[
+		/xyz/,
+		/Emitted value instead of an instance of Error/,
+		/warning-loader\.js/
+	]
 ];