issue:checkout: fetch remote before checkout when remote already exists

[Copilot]

issue:checkout only fetched the remote when it was being newly added. If the remote already existed locally (manually added, or stale from a previous session), no fetch occurred before the checkout attempt, causing git checkout -b <branch> --track <remote>/<branch> to fail with a missing ref error.

Changes

• Checkout.php: Added git fetch <remote> in the branch where the remote already exists, ensuring local tracking refs are always up-to-date before the checkout. Fetch failure surfaces an explicit error message and exits early.

Remote exists → git fetch <remote>  ← new
             ↓
git checkout -b <branch> --track <remote>/<branch>

The "remote not found" path (via SetupIssueRemoteAction) already fetched after adding — this change closes the gap for the pre-existing remote case.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>issue:checkout needs to fetch the remote after adding issue fork remote</issue_title>
<issue_description>not sure if issue:setup-remote needs this as well. used issue:checkout and checking out the branch failed because the new remote was not fetched</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes issue:checkout needs to fetch the remote after adding issue fork remote #329

---

📱 Kick off Copilot coding agent tasks wherever you are with GitHub Mobile, available on iOS and Android.

[Copilot]

Pull request overview

This PR fixes issue:checkout failing to track a remote branch when the issue fork remote already exists locally by ensuring the remote is fetched before attempting the checkout.

Changes:

• When the expected remote already exists, run git fetch <remote> before git checkout -b ... --track ....
• Surface a clear fetch failure message and exit early if the fetch fails.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[mglaman]

@copilot I didn't have the remote setup, can we verify ,SetupIssueRemoteAction does the fetch of the remote as well

[Copilot]

@copilot I didn't have the remote setup, can we verify ,SetupIssueRemoteAction does the fetch of the remote as well

Yes — SetupIssueRemoteAction::__invoke() always runs git fetch <remote> unconditionally (lines 46–55), regardless of whether the remote was newly added or already existed. So both paths are covered: newly-added remote (add → fetch) and pre-existing remote (skip add → fetch). No changes needed there.