fix: correct error when remote repository has no branches

lib/git.js

@@ -65,8 +65,8 @@ async function getCommits(from, to, execaOpts) {
 async function getBranches(repositoryUrl, execaOpts) {
   return (await execa('git', ['ls-remote', '--heads', repositoryUrl], execaOpts)).stdout
     .split('\n')
-    .map(branch => branch.match(/^.+refs\/heads\/(?<branch>.+)$/)[1])
-    .filter(Boolean);
+    .filter(Boolean)
+    .map(branch => branch.match(/^.+refs\/heads\/(?<branch>.+)$/)[1]);
 }
 
 /**

test/git.test.js

@@ -33,6 +33,7 @@ import {
   gitAddNote,
   gitGetNote,
   gitFetch,
+  initGit,
 } from './helpers/git-utils';
 
 test('Get the last commit sha', async t => {
@@ -182,6 +183,11 @@ test('Get all branches', async t => {
   t.deepEqual((await getBranches(repositoryUrl, {cwd})).sort(), ['master', 'second-branch', 'third-branch'].sort());
 });
 
+test('Return empty array if there are no branches', async t => {
+  const {cwd, repositoryUrl} = await initGit(true);
+  t.deepEqual(await getBranches(repositoryUrl, {cwd}), []);
+});
+
 test('Get the commit sha for a given tag', async t => {
   // Create a git repository, set the current working directory at the root of the repo
   const {cwd} = await gitRepo();

test/helpers/git-utils.js

@@ -7,29 +7,42 @@ import getStream from 'get-stream';
 import {GIT_NOTE_REF} from '../../lib/definitions/constants';
 
 /**
- * Commit message informations.
+ * Commit message information.
  *
  * @typedef {Object} Commit
  * @property {String} branch The commit branch.
  * @property {String} hash The commit hash.
  * @property {String} message The commit message.
  */
 
+/**
+ * Initialize git repository
+ * If `withRemote` is `true`, creates a bare repository and initialize it.
+ * If `withRemote` is `false`, creates a regular repository and initialize it.
+ *
+ * @param {Boolean} withRemote `true` to create a shallow clone of a bare repository.
+ * @return {String} The path of the repository
+ */
+export async function initGit(withRemote) {
+  const cwd = tempy.directory();
+
+  await execa('git', ['init', ...(withRemote ? ['--bare'] : [])], {cwd});
+  const repositoryUrl = fileUrl(cwd);
+  return {cwd, repositoryUrl};
+}
+
 /**
  * Create a temporary git repository.
- * If `withRemote` is `true`, creates a bare repository, initialize it and create a shallow clone. Change the current working directory to the clone root.
- * If `withRemote` is `false`, creates a regular repository and initialize it. Change the current working directory to the repository root.
+ * If `withRemote` is `true`, creates a shallow clone. Change the current working directory to the clone root.
+ * If `withRemote` is `false`, just change the current working directory to the repository root.
+ *
  *
  * @param {Boolean} withRemote `true` to create a shallow clone of a bare repository.
  * @param {String} [branch='master'] The branch to initialize.
  * @return {String} The path of the clone if `withRemote` is `true`, the path of the repository otherwise.
  */
 export async function gitRepo(withRemote, branch = 'master') {
-  let cwd = tempy.directory();
-
-  await execa('git', ['init', ...(withRemote ? ['--bare'] : [])], {cwd});
-
-  const repositoryUrl = fileUrl(cwd);
+  let {cwd, repositoryUrl} = await initGit(withRemote);
   if (withRemote) {
     await initBareRepo(repositoryUrl, branch);
     cwd = await gitShallowClone(repositoryUrl, branch);