feat(core): readd support for .conventional-changelog-lintrc

@commitlint/core/fixtures/legacy/.conventional-changelog-lintrc

@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "legacy": true
+  }
+}

@commitlint/core/fixtures/overriden-legacy/.commitlintrc

@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "legacy": false
+  }
+}

@commitlint/core/fixtures/overriden-legacy/.conventional-changelog-lintrc

@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "legacy": true
+  }
+}

@commitlint/core/src/load.js

@@ -10,7 +10,7 @@ const valid = input => pick(input, 'extends', 'rules');
 
 export default async (seed = {}) => {
 	// Obtain config from .rc files
-	const raw = rc('commitlint');
+	const raw = file();
 	const found = typeof raw.config === 'string';
 
 	// Use the default extends config if there is no userConfig file found
@@ -58,3 +58,25 @@ export default async (seed = {}) => {
 		};
 	}, preset);
 };
+
+function file() {
+	const legacy = rc('conventional-changelog-lint');
+	const legacyFound = typeof legacy.config === 'string';
+
+	const raw = rc('commitlint');
+	const rawFound = typeof raw.config === 'string';
+
+	if (legacyFound && !rawFound) {
+		console.warn(`Using legacy ${path.relative(process.cwd(), legacy.config)}. Rename to .commitlintrc to silence this warning.`);
+	}
+
+	if (legacyFound && rawFound) {
+		console.warn(`Ignored legacy ${path.relative(process.cwd(), legacy.config)} as ${path.relative(process.cwd(), raw.config)} superseeds it. Remove .conventional-changelog-lintrc to silence this warning.`);
+	}
+
+	if (rawFound) {
+		return raw;
+	}
+
+	return legacy;
+}

@commitlint/core/src/load.test.js

@@ -74,6 +74,26 @@ test('ignores unknow keys recursively', async t => {
 	});
 });
 
+test('supports legacy .conventional-changelog-lintrc', async t => {
+	t.context.back = chdir('fixtures/legacy');
+	const actual = await load();
+	t.deepEqual(actual, {
+		rules: {
+			legacy: true
+		}
+	});
+});
+
+test('.commitlintrc overrides .conventional-changelog-lintrc', async t => {
+	t.context.back = chdir('fixtures/overriden-legacy');
+	const actual = await load();
+	t.deepEqual(actual, {
+		rules: {
+			legacy: false
+		}
+	});
+});
+
 function chdir(target) {
 	const to = path.resolve(cwd, target.split('/').join(path.sep));
 	process.chdir(to);