From 3321f3138e554d41ffca1ac880803dfd2ac1e105 Mon Sep 17 00:00:00 2001
From: James George <jamesgeorge998001@gmail.com>
Date: Wed, 19 Jun 2019 20:05:43 +0530
Subject: [PATCH 1/3] Handle cryptic error message being thrown

misconfigured config file
---
 lib/webpack.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/webpack.js b/lib/webpack.js
index 2362951c4d9..f8dffa72f43 100644
--- a/lib/webpack.js
+++ b/lib/webpack.js
@@ -32,7 +32,7 @@ const webpack = (options, callback) => {
 	}
 	let compiler;
 	if (Array.isArray(options)) {
-		compiler = new MultiCompiler(options.map(options => webpack(options)));
+		compiler = new MultiCompiler(Array.from(options).map(options => webpack(options)));
 	} else if (typeof options === "object") {
 		options = new WebpackOptionsDefaulter().process(options);
 

From 0109d687a67aa3bd717ce36ce3fd88c1e6aa1af7 Mon Sep 17 00:00:00 2001
From: jamesgeorge007 <jamesgeorge998001@gmail.com>
Date: Wed, 19 Jun 2019 20:29:37 +0530
Subject: [PATCH 2/3] Linting fix

---
 lib/webpack.js | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/webpack.js b/lib/webpack.js
index f8dffa72f43..3e121f41fa9 100644
--- a/lib/webpack.js
+++ b/lib/webpack.js
@@ -32,7 +32,9 @@ const webpack = (options, callback) => {
 	}
 	let compiler;
 	if (Array.isArray(options)) {
-		compiler = new MultiCompiler(Array.from(options).map(options => webpack(options)));
+		compiler = new MultiCompiler(
+			Array.from(options).map(options => webpack(options))
+		);
 	} else if (typeof options === "object") {
 		options = new WebpackOptionsDefaulter().process(options);
 

From 226e8ce8fd9fee33e8d8b37dd4d7d9c24483b4f9 Mon Sep 17 00:00:00 2001
From: Tobias Koppers <tobias.koppers@googlemail.com>
Date: Wed, 19 Jun 2019 18:55:27 +0200
Subject: [PATCH 3/3] add test case for holey array

---
 test/Validation.test.js | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/test/Validation.test.js b/test/Validation.test.js
index e82f8de54fa..694dcd39b33 100644
--- a/test/Validation.test.js
+++ b/test/Validation.test.js
@@ -404,6 +404,25 @@ describe("Validation", () => {
  - configuration.mode should be one of these:
    \\"development\\" | \\"production\\" | \\"none\\"
    -> Enable production optimizations or development hints."
+`)
+	);
+
+	createTestCase(
+		"holey array",
+		// eslint-disable-next-line no-sparse-arrays
+		[
+			{
+				mode: "production"
+			},
+			,
+			{
+				mode: "development"
+			}
+		],
+		msg =>
+			expect(msg).toMatchInlineSnapshot(`
+"Invalid configuration object. Webpack has been initialised using a configuration object that does not match the API schema.
+ - configuration should be an object."
 `)
 	);
 });