From bc368c76119d75981b7d9153cd1c3c52c17dc564 Mon Sep 17 00:00:00 2001
From: Tobias Koppers <tobias.koppers@googlemail.com>
Date: Sat, 22 Dec 2018 13:39:26 +0100
Subject: [PATCH] fixes #8538

---
 lib/IgnorePlugin.js                            |  2 ++
 .../multiple-with-externals/ignored-module1.js |  1 +
 .../multiple-with-externals/ignored-module2.js |  1 +
 .../multiple-with-externals/normal-module.js   |  1 +
 .../ignore/multiple-with-externals/test.js     | 18 ++++++++++++++++++
 .../multiple-with-externals/webpack.config.js  | 18 ++++++++++++++++++
 6 files changed, 41 insertions(+)
 create mode 100644 test/configCases/ignore/multiple-with-externals/ignored-module1.js
 create mode 100644 test/configCases/ignore/multiple-with-externals/ignored-module2.js
 create mode 100644 test/configCases/ignore/multiple-with-externals/normal-module.js
 create mode 100644 test/configCases/ignore/multiple-with-externals/test.js
 create mode 100644 test/configCases/ignore/multiple-with-externals/webpack.config.js

diff --git a/lib/IgnorePlugin.js b/lib/IgnorePlugin.js
index a90f7edea..cd824db2b 100644
--- a/lib/IgnorePlugin.js
+++ b/lib/IgnorePlugin.js
@@ -38,6 +38,8 @@ class IgnorePlugin {
 	 * @returns {TODO|null} returns result or null if result should be ignored
 	 */
 	checkIgnore(result) {
+		if (!result) return result;
+
 		if (
 			"checkResource" in this.options &&
 			this.options.checkResource &&
diff --git a/test/configCases/ignore/multiple-with-externals/ignored-module1.js b/test/configCases/ignore/multiple-with-externals/ignored-module1.js
new file mode 100644
index 000000000..4e015a52c
--- /dev/null
+++ b/test/configCases/ignore/multiple-with-externals/ignored-module1.js
@@ -0,0 +1 @@
+module.exports = "ignored";
diff --git a/test/configCases/ignore/multiple-with-externals/ignored-module2.js b/test/configCases/ignore/multiple-with-externals/ignored-module2.js
new file mode 100644
index 000000000..4e015a52c
--- /dev/null
+++ b/test/configCases/ignore/multiple-with-externals/ignored-module2.js
@@ -0,0 +1 @@
+module.exports = "ignored";
diff --git a/test/configCases/ignore/multiple-with-externals/normal-module.js b/test/configCases/ignore/multiple-with-externals/normal-module.js
new file mode 100644
index 000000000..f5f8a087f
--- /dev/null
+++ b/test/configCases/ignore/multiple-with-externals/normal-module.js
@@ -0,0 +1 @@
+module.exports = "normal";
diff --git a/test/configCases/ignore/multiple-with-externals/test.js b/test/configCases/ignore/multiple-with-externals/test.js
new file mode 100644
index 000000000..caa14b2ab
--- /dev/null
+++ b/test/configCases/ignore/multiple-with-externals/test.js
@@ -0,0 +1,18 @@
+/* globals it */
+"use strict";
+
+it("should ignore ignored resources 1", function() {
+	expect(function() {
+		require("./ignored-module1");
+	}).toThrowError();
+});
+it("should ignore ignored resources 2", function() {
+	expect(function() {
+		require("./ignored-module2");
+	}).toThrowError();
+});
+it("should not ignore resources that do not match", function() {
+	expect(function() {
+		require("./normal-module");
+	}).not.toThrowError();
+});
diff --git a/test/configCases/ignore/multiple-with-externals/webpack.config.js b/test/configCases/ignore/multiple-with-externals/webpack.config.js
new file mode 100644
index 000000000..d1cc2d086
--- /dev/null
+++ b/test/configCases/ignore/multiple-with-externals/webpack.config.js
@@ -0,0 +1,18 @@
+"use strict";
+
+const IgnorePlugin = require("../../../../lib/IgnorePlugin");
+
+module.exports = {
+	entry: "./test.js",
+	externals: {
+		"./normal-module": "{}"
+	},
+	plugins: [
+		new IgnorePlugin({
+			resourceRegExp: /ignored-module1/
+		}),
+		new IgnorePlugin({
+			resourceRegExp: /ignored-module2/
+		})
+	]
+};