This is similar to bug 129701, that running commit in a checkout of a readonly branch gives a traceback. However, there is a difference, which is that running commit in a readonly branch really should fail (but cleanly), whereas running update should not fail at all.
This is similar to bug 129701, that running commit in a checkout of a readonly branch gives a traceback. However, there is a difference, which is that running commit in a readonly branch really should fail (but cleanly), whereas running update should not fail at all.