feat: edit flag now accepts the path to the commit file

Closes #40.

Author: satazor

Diff for: @commitlint/cli/cli.js

@@ -23,8 +23,8 @@ const rules = {
 };
 
 const configuration = {
-	string: ['cwd', 'from', 'to', 'extends', 'parser-preset'],
-	boolean: ['edit', 'help', 'version', 'quiet', 'color'],
+	string: ['cwd', 'from', 'to', 'edit', 'extends', 'parser-preset'],
+	boolean: ['help', 'version', 'quiet', 'color'],
 	alias: {
 		c: 'color',
 		d: 'cwd',
@@ -40,7 +40,8 @@ const configuration = {
 	description: {
 		color: 'toggle colored output',
 		cwd: 'directory to execute in',
-		edit: 'read last commit message found in ./.git/COMMIT_EDITMSG',
+		edit:
+			'read last commit message from the specified file or fallbacks to ./.git/COMMIT_EDITMSG',
 		extends: 'array of shareable configurations to extend',
 		from: 'lower end of the commit range to lint; applies if edit=false',
 		to: 'upper end of the commit range to lint; applies if edit=false',
@@ -74,6 +75,8 @@ const cli = meow(
 const load = (seed, opts) => core.load(seed, opts);
 
 function main(options) {
+	normalizeOptions(options);
+
 	const raw = options.input;
 	const flags = options.flags;
 	const fromStdin = rules.fromStdin(raw, flags);
@@ -113,6 +116,17 @@ function main(options) {
 	);
 }
 
+function normalizeOptions(options) {
+	const flags = options.flags;
+
+	// The `edit` flag is either a boolean or a string but we are only allowed
+	// to specify one of them in minimist
+	if (flags.edit === '') {
+		flags.edit = true;
+		flags.e = true;
+	}
+}
+
 function getSeed(seed) {
 	const e = Array.isArray(seed.extends) ? seed.extends : [seed.extends];
 	const n = e.filter(i => typeof i === 'string');

Diff for: @commitlint/core/src/read.js

@@ -19,7 +19,7 @@ async function getCommitMessages(settings) {
 	const {cwd, from, to, edit} = settings;
 
 	if (edit) {
-		return getEditCommit(cwd);
+		return getEditCommit(cwd, edit);
 	}
 
 	if (await isShallow(cwd)) {
@@ -57,15 +57,19 @@ async function isShallow(cwd) {
 }
 
 // Get recently edited commit message
-// (cwd: string) => Promise<Array<String>>
-async function getEditCommit(cwd) {
+// (cwd: string, edit: any) => Promise<Array<String>>
+async function getEditCommit(cwd, edit) {
 	const top = await toplevel(cwd);
 
 	if (typeof top !== 'string') {
 		throw new TypeError(`Could not find git root from ${cwd}`);
 	}
 
-	const editFilePath = path.join(top, '.git/COMMIT_EDITMSG');
+	const editFilePath =
+		typeof edit === 'string'
+			? path.resolve(top, edit)
+			: path.join(top, '.git/COMMIT_EDITMSG');
+
 	const editFile = await sander.readFile(editFilePath);
 	return [`${editFile.toString('utf-8')}\n`];
 }

Diff for: @commitlint/core/src/read.test.js

@@ -6,6 +6,16 @@ import * as sander from '@marionebl/sander';
 import pkg from '../package';
 import read from './read';
 
+test('get edit commit message specified by the `edit` flag', async t => {
+	const cwd = await git.bootstrap();
+
+	await sander.writeFile(cwd, 'commit-msg-file', 'foo');
+
+	const expected = ['foo\n'];
+	const actual = await read({edit: 'commit-msg-file', cwd});
+	t.deepEqual(actual, expected);
+});
+
 test('get edit commit message from git root', async t => {
 	const cwd = await git.bootstrap();