Re: [PATCH] odb: do not list our own refs as alternate refs in the quarantine

>
> This indeed sounds like a bit of a hack. To me the underlying issue here
> is that downstream git processes don't really have any concept of an ODB
> transaction. We rely on the git alternates mechanism and overriding the
> primary object directory to get the unaware child processes to behave
> how we want. This typically means setting the quarantine directory as
> the main object directory and the "real" object directory as an
> alternate via environment variables. That way any writes that are
> performed by a child process are written to the quarantine.
>
> For the connectivity check though, we don't really expect
> git-rev-list(1) to write any objects. Consequently, I don't think we
> neccessary need to set the quarantine directory as the primary object
> directory here. That would avoid git-rev-list(1) processing the "real"
> object directory references a second time.

> >     So the question is really where this should be fixed: is there a better
> >     way for processes running inside the quarantine to tell the repository's
> >     own object directory apart from real alternates?
>
> Building off of my previous thoughts, maybe it would make sense to make
> the connectivity check a more explicit part of the ODB transaction
> interface? Maybe for the "files" backend we could introduce a
> `odb_transaction_files_check_connected()` callback that configures
> git-rev-list(1) with the appropriate environment to validate the
> quarantined objects and not cause this bug? Happy to explore this path
> further if it seems reasonable.
>
> -Justin