fix(load): resolve plugins from extended configs

@commitlint/load/fixtures/extends-with-local-plugins/commitlint.config.js

@@ -0,0 +1,3 @@
+module.exports = {
+	extends: ['./config-with-local-plugin'],
+};

@commitlint/load/fixtures/extends-with-local-plugins/config-with-local-plugin/commitlint.config.js

@@ -0,0 +1,21 @@
+module.exports = {
+	extends: [],
+	plugins: [{
+		rules: {
+			'hello-world-rule': ({ subject }) => {
+				const HELLO_WORLD = 'Hello World';
+				return [
+				  subject.includes(HELLO_WORLD),
+				  `Your subject should contain ${HELLO_WORLD} message`
+				];
+			 },
+			 'is-positive': ({ subject }) => {
+				const POSITIVE_EMOJI = ':)';
+				return [
+				  subject.includes(POSITIVE_EMOJI),
+				  `Your subject should contain ${POSITIVE_EMOJI} message`
+				];
+			 }
+  		}
+	}]
+};

@commitlint/load/fixtures/extends-with-local-plugins/config-with-local-plugin/index.js

@@ -0,0 +1 @@
+module.exports = require('./commitlint.config.js');

@commitlint/load/fixtures/extends-with-plugins/commitlint.config.js

@@ -0,0 +1,3 @@
+module.exports = {
+	extends: ['./config-with-plugins'],
+};

@commitlint/load/fixtures/extends-with-plugins/config-with-plugins/commitlint.config.js

@@ -0,0 +1,3 @@
+module.exports = {
+	plugins: ['example', '@scope/example']
+};

@commitlint/load/fixtures/extends-with-plugins/config-with-plugins/index.js

@@ -0,0 +1 @@
+module.exports = require('./commitlint.config.js');

@commitlint/load/src/load.test.ts

@@ -95,6 +95,32 @@ test('plugins should be loaded from config', async () => {
 	});
 });
 
+test('plugins should be loaded from shareable config', async () => {
+	const cwd = await gitBootstrap('fixtures/extends-with-plugins');
+	const actual = await load({}, {cwd});
+
+	expect(actual.plugins).toMatchObject({
+		example: plugin,
+		'@scope/example': scopedPlugin
+	});
+});
+
+test('local plugins should be loaded from shareable configs', async () => {
+	const cwd = await gitBootstrap('fixtures/extends-with-local-plugins');
+	const actual = await load({}, {cwd});
+
+	expect(actual.plugins).toEqual(
+		expect.objectContaining({
+			local: {
+				rules: {
+					'hello-world-rule': expect.any(Function),
+					'is-positive': expect.any(Function)
+				}
+			}
+		})
+	);
+});
+
 test('uses seed with parserPreset', async () => {
 	const cwd = await gitBootstrap('fixtures/parser-preset');
 	const {parserPreset: actual} = await load(

@commitlint/load/src/load.ts

@@ -3,6 +3,7 @@ import Path from 'path';
 import merge from 'lodash/merge';
 import mergeWith from 'lodash/mergeWith';
 import pick from 'lodash/pick';
+import union from 'lodash/union';
 import resolveFrom from 'resolve-from';
 
 import executeRule from '@commitlint/execute-rule';
@@ -84,6 +85,10 @@ export default async function load(
 			resolveFrom.silent(base, config.formatter) || config.formatter;
 	}
 
+	// Read plugins from extends
+	if (Array.isArray(extended.plugins))
+		config.plugins = union(config.plugins, extended.plugins || []);
+
 	// resolve plugins
 	if (Array.isArray(config.plugins)) {
 		config.plugins.forEach(plugin => {