Given the scenario of 3 peers, A, B, and C each having a project R. If
peer A has B's fork, but C does not, then when peer A attempts to
fetch from C the fetch will be rejected since Git will fail when a
refspec that is asked for does not exist on the remote side.
To avoid this, the fetch logic is changed so that the client first calls
ls-remote to the remote side, which results in the references that the
remote has which the client is interested in. The follow-up fetch then
uses these refs as the refspecs -- which should succeed unless there
was a race for a deletion on the remote side.
The rest of the verification logic stays the same, so the storage
should still be in a working state before transferring from the staged
repository to the production repository.
Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett
Previously, during the "transfer" stage of a fetch, we used `force:
false`, which didn't allow refs to be force-updated.
This change makes it possible to fetch force-updated refs, but ensures
that the sigrefs branch is never force-updated.
The One variant caused many paint points for fetching logic, where it
was not necessary. It was only constructed in one place, which could
be replaced by using the variant that holds a set of keys.
Remove the Namespaces::One variant and rename Namespaces::Many to
Namespaces::Trusted.
Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett
The previous fetching logic had some pitfalls regarding its logic:
* Fetched 'rad' references could end up not being verifiable and leaving
the storage in a corrupt state
* Forced pushes would be prohibited, since they would be rejected by
the client side due to the refspecs being used.
The new approach is to stage a fetch in 2 steps. The first step is to
fetch the relevant `rad/id` and `rad/sigrefs` for verification. For
all remotes that are verified, fetch all references listed in their
respective `rad/sigrefs`, using the `+` marker in the refspec,
allowing to update for any force pushes -- note that this becomes a
safe operation since the `sigrefs` are signed by the remote that
created them.
To prevent unverifiable 'rad' references from polluting storage, all
fetch negotiations are done in a staging repository set up in a
temporary directory. All successful fetches are then transferred,
using the 'file://' protocol, from the temporary directory into the
radicle storage.
Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett
Fintan Halpenny
Alexis Sellier