fix(resolve-extends): override array on extending rules (#470) (#539)

@commitlint/resolve-extends/src/index.js

@@ -3,13 +3,18 @@ import path from 'path';
 import 'resolve-global'; // eslint-disable-line import/no-unassigned-import
 import requireUncached from 'require-uncached';
 import resolveFrom from 'resolve-from';
-import {merge, omit} from 'lodash';
+import {isArray, merge, mergeWith, omit} from 'lodash';
 
 // Resolve extend configs
 export default function resolveExtends(config = {}, context = {}) {
 	const {extends: e} = config;
 	const extended = loadExtends(config, context).reduceRight(
-		(r, c) => merge(r, omit(c, 'extends')),
+		(r, c) =>
+			mergeWith(r, omit(c, 'extends'), (objValue, srcValue) => {
+				if (isArray(objValue)) {
+					return srcValue;
+				}
+			}),
 		e ? {extends: e} : {}
 	);
 

@commitlint/resolve-extends/src/index.test.js

@@ -190,6 +190,34 @@ test('propagates contents recursively', t => {
 	t.deepEqual(actual, expected);
 });
 
+test('propagates contents recursively with overlap', t => {
+	const input = {extends: ['extender-name']};
+
+	const actual = resolveExtends(input, {
+		resolve: id,
+		require(id) {
+			if (id === 'extender-name') {
+				return {
+					extends: ['recursive-extender-name'],
+					rules: {rule: ['zero', 'one']}
+				};
+			}
+			if (id === 'recursive-extender-name') {
+				return {rules: {rule: ['two', 'three', 'four']}};
+			}
+		}
+	});
+
+	const expected = {
+		extends: ['extender-name'],
+		rules: {
+			rule: ['zero', 'one']
+		}
+	};
+
+	t.deepEqual(actual, expected);
+});
+
 test('extending contents should take precedence', t => {
 	const input = {extends: ['extender-name'], zero: 'root'};