From b94f32271e77246354852d8e6b417d4ea861f052 Mon Sep 17 00:00:00 2001
From: Mike Spiegel <mspiegel31@gmail.com>
Date: Thu, 28 Sep 2023 15:47:58 -0400
Subject: [PATCH] support fetching tags

Signed-off-by: Mike Spiegel <mspiegel31@gmail.com>
---
 .changeset/itchy-bobcats-fly.md             | 5 +++++
 packages/backend-common/api-report.md       | 6 +++++-
 packages/backend-common/src/scm/git.test.ts | 4 +++-
 packages/backend-common/src/scm/git.ts      | 9 +++++++--
 4 files changed, 20 insertions(+), 4 deletions(-)
 create mode 100644 .changeset/itchy-bobcats-fly.md

diff --git a/.changeset/itchy-bobcats-fly.md b/.changeset/itchy-bobcats-fly.md
new file mode 100644
index 0000000000..e91d944478
--- /dev/null
+++ b/.changeset/itchy-bobcats-fly.md
@@ -0,0 +1,5 @@
+---
+'@backstage/backend-common': patch
+---
+
+Added the ability to fetch git tags through the `Git` class. This is useful for scaffolder actions that want to take action based on tag versions in a cloned repository
diff --git a/packages/backend-common/api-report.md b/packages/backend-common/api-report.md
index ab640ccd9b..36cb225a27 100644
--- a/packages/backend-common/api-report.md
+++ b/packages/backend-common/api-report.md
@@ -377,7 +377,11 @@ export class Git {
   }): Promise<string | undefined>;
   // (undocumented)
   deleteRemote(options: { dir: string; remote: string }): Promise<void>;
-  fetch(options: { dir: string; remote?: string }): Promise<void>;
+  fetch(options: {
+    dir: string;
+    remote?: string;
+    tags?: boolean;
+  }): Promise<void>;
   // (undocumented)
   static fromAuth: (options: {
     username?: string;
diff --git a/packages/backend-common/src/scm/git.test.ts b/packages/backend-common/src/scm/git.test.ts
index 629173f96e..5ec960fc53 100644
--- a/packages/backend-common/src/scm/git.test.ts
+++ b/packages/backend-common/src/scm/git.test.ts
@@ -264,13 +264,14 @@ describe('Git', () => {
       };
       const git = Git.fromAuth(auth);
 
-      await git.fetch({ remote, dir });
+      await git.fetch({ remote, dir, tags: true });
 
       expect(isomorphic.fetch).toHaveBeenCalledWith({
         fs,
         http,
         remote,
         dir,
+        tags: true,
         onProgress: expect.any(Function),
         headers: {
           'user-agent': 'git/@isomorphic-git',
@@ -294,6 +295,7 @@ describe('Git', () => {
         http,
         remote,
         dir,
+        tags: false,
         onProgress: expect.any(Function),
         headers: {
           Authorization: 'Bearer test',
diff --git a/packages/backend-common/src/scm/git.ts b/packages/backend-common/src/scm/git.ts
index 234ae57d30..8ccdbeafbd 100644
--- a/packages/backend-common/src/scm/git.ts
+++ b/packages/backend-common/src/scm/git.ts
@@ -160,8 +160,12 @@ export class Git {
   }
 
   /** https://isomorphic-git.org/docs/en/fetch */
-  async fetch(options: { dir: string; remote?: string }): Promise<void> {
-    const { dir, remote = 'origin' } = options;
+  async fetch(options: {
+    dir: string;
+    remote?: string;
+    tags?: boolean;
+  }): Promise<void> {
+    const { dir, remote = 'origin', tags = false } = options;
     this.config.logger?.info(
       `Fetching remote=${remote} for repository {dir=${dir}}`,
     );
@@ -172,6 +176,7 @@ export class Git {
         http,
         dir,
         remote,
+        tags,
         onProgress: this.onProgressHandler(),
         headers: this.headers,
         onAuth: this.onAuth,