Comment 1 for bug 261315

I can reproduce it using mwh's script.

The InterPackRepo's source is a KnitPackRepository which (unsurprisingly but incorrectly) has no fallback repositories configured; this would explain why we can't find the revision. We're using InterPackRepo because the current InterRemoteToOther always gets the real repository and fetches through that.

I suspect the problem is that the repository is somewhere being opened directly, rather than through the branch object, which is responsible for configuring the fallbacks into the repository when it is opened.

Going up the stack, I see the RemoteRepository also does not have fallback repositories configured, which is probably how it should be if this is to be hidden on the server side.