fix: fetch tags on repo cached by the CI

lib/git.js

@@ -86,15 +86,22 @@ async function isRefExists(ref, execaOpts) {
 }
 
 /**
- * Unshallow the git repository if necessary and fetch all the tags.
+ * Fetch all the tags from a branch. Unshallow if necessary.
+ * This will update the local branch from the latest on the remote if:
+ * - The branch is not the one that triggered the CI
+ * - The CI created a detached head
+ *
+ * Otherwise it just calls `git fetch` without specifying the `refspec` option to avoid overwritting the head commit set by the CI.
+ *
+ * The goal is to retrieve the informations on all the release branches without "disturbing" the CI, leaving the trigger branch or the detached head intact.
  *
  * @param {String} repositoryUrl The remote repository URL.
  * @param {String} branch The repository branch to fetch.
  * @param {Object} [execaOpts] Options to pass to `execa`.
  */
 async function fetch(repositoryUrl, branch, ciBranch, execaOpts) {
-  const isLocalExists =
-    (await execa('git', ['rev-parse', '--verify', branch], {...execaOpts, reject: false})).exitCode === 0;
+  const isDetachedHead =
+    (await execa('git', ['rev-parse', '--abbrev-ref', 'HEAD'], {...execaOpts, reject: false})).stdout === 'HEAD';
 
   try {
     await execa(
@@ -103,7 +110,7 @@ async function fetch(repositoryUrl, branch, ciBranch, execaOpts) {
         'fetch',
         '--unshallow',
         '--tags',
-        ...(branch === ciBranch && isLocalExists
+        ...(branch === ciBranch && !isDetachedHead
           ? [repositoryUrl]
           : ['--update-head-ok', repositoryUrl, `+refs/heads/${branch}:refs/heads/${branch}`]),
       ],
@@ -115,7 +122,7 @@ async function fetch(repositoryUrl, branch, ciBranch, execaOpts) {
       [
         'fetch',
         '--tags',
-        ...(branch === ciBranch && isLocalExists
+        ...(branch === ciBranch && !isDetachedHead
           ? [repositoryUrl]
           : ['--update-head-ok', repositoryUrl, `+refs/heads/${branch}:refs/heads/${branch}`]),
       ],

test/git.test.js

@@ -32,6 +32,7 @@ import {
   gitDetachedHeadFromBranch,
   gitAddNote,
   gitGetNote,
+  gitFetch,
 } from './helpers/git-utils';
 
 test('Get the last commit sha', async t => {
@@ -99,7 +100,7 @@ test('Fetch all tags on a detached head repository', async t => {
   t.deepEqual((await getTags('master', {cwd})).sort(), ['v1.0.0', 'v1.0.1', 'v1.1.0'].sort());
 });
 
-test('Fetch all tags on a repository with a detached head from branch', async t => {
+test('Fetch all tags on a repository with a detached head from branch (CircleCI)', async t => {
   let {cwd, repositoryUrl} = await gitRepo();
 
   await gitCommits(['First'], {cwd});
@@ -124,6 +125,34 @@ test('Fetch all tags on a repository with a detached head from branch', async t
   t.deepEqual((await getTags('master', {cwd})).sort(), ['v1.0.0', 'v1.0.1', 'v1.1.0', 'v2.0.0'].sort());
 });
 
+test('Fetch all tags on a detached head repository with outdated cached repo (GitLab CI)', async t => {
+  const {cwd, repositoryUrl} = await gitRepo();
+
+  await gitCommits(['First'], {cwd});
+  await gitTagVersion('v1.0.0', undefined, {cwd});
+  await gitCommits(['Second'], {cwd});
+  await gitTagVersion('v1.0.1', undefined, {cwd});
+  let [commit] = await gitCommits(['Third'], {cwd});
+  await gitTagVersion('v1.1.0', undefined, {cwd});
+  await gitPush(repositoryUrl, 'master', {cwd});
+
+  // Create a clone (as first CI run would)
+  const cloneCwd = await gitShallowClone(repositoryUrl);
+  await gitFetch(repositoryUrl, {cwd: cloneCwd});
+  await gitCheckout(commit.hash, false, {cwd: cloneCwd});
+
+  // Push tag to remote
+  [commit] = await gitCommits(['Fourth'], {cwd});
+  await gitTagVersion('v1.2.0', undefined, {cwd});
+  await gitPush(repositoryUrl, 'master', {cwd});
+
+  // Fetch on the cached repo and make detached head, leaving master outdated
+  await fetch(repositoryUrl, 'master', 'master', {cwd: cloneCwd});
+  await gitCheckout(commit.hash, false, {cwd: cloneCwd});
+
+  t.deepEqual((await getTags('master', {cwd: cloneCwd})).sort(), ['v1.0.0', 'v1.0.1', 'v1.1.0', 'v1.2.0'].sort());
+});
+
 test('Verify if a branch exists', 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

@@ -109,6 +109,16 @@ export async function gitCheckout(branch, create, execaOpts) {
   await execa('git', create ? ['checkout', '-b', branch] : ['checkout', branch], execaOpts);
 }
 
+/**
+ * Fetch current git repository.
+ *
+ * @param {String} repositoryUrl The repository remote URL.
+ * @param {Object} [execaOpts] Options to pass to `execa`.
+ */
+export async function gitFetch(repositoryUrl, execaOpts) {
+  await execa('git', ['fetch', repositoryUrl], execaOpts);
+}
+
 /**
  * Get the HEAD sha.
  *