/review does not handle reviewing a branch from a fork.

What version of the Codex App are you using (From “About Codex” dialog)?

260204.1342 (531)

What subscription do you have?

Enterprise

What issue are you seeing?

Summary

In a repo with multiple remotes (e.g., origin and upstream), the base branch selector shows only main without the remote name. This makes it easy to compare against the wrong remote (e.g., origin/main instead of upstream/main), leading to incorrect diffs and review findings.

Update

I thought to work around the ambiguity by renaming the default branch of my fork to my username, and now I can't see the main branch on the upstream repo at all.

<img width="747" height="74" alt="Image" src="https://github.com/user-attachments/assets/975e2690-b69f-4cb9-809e-efeb0ea54116" />

Impact

Reviews can be performed against the wrong base branch without any warning or disambiguation.

What steps can reproduce the bug?

Steps to Reproduce

1. Open a Git repo with two remotes, both having a main branch (e.g., origin/main and upstream/main).
2. Start a Codex review and pick “main” as the base branch from the selector.
3. Observe that the selector does not show the remote name, and the review compares against an unintended main.

Evidence

• Screenshot of the base branch selector (attached).

<img width="1486" height="502" alt="Image" src="https://github.com/user-attachments/assets/09ccb94f-8a3d-401e-9828-262ad043ec18" />

What is the expected behavior?

The base branch selector should disambiguate remotes, e.g., showing origin/main and upstream/main, or provide a way to choose the remote explicitly. The review should honor the exact remote the user intended.

Additional information

Report drafted by Codex based on user-provided screenshots and repro steps.