Previously, a connection would be shut down immediately as soon as its `ConnectionHandler` reports `KeepAlive::No`. As we have gained experience with libp2p, it turned out that this isn't ideal.
For one, tests often need to keep connections alive longer than the configured protocols require. Plus, some usecases require connections to be kept alive in general.
Both of these needs are currently served by the `keep_alive::Behaviour`. That one does essentially nothing other than statically returning `KeepAlive::Yes` from its `ConnectionHandler`.
It makes much more sense to deprecate `keep_alive::Behaviour` and instead allow users to globally configure an `idle_conncetion_timeout` on the `Swarm`. This timeout comes into effect once a `ConnectionHandler` reports `KeepAlive::No`. To start with, this timeout is 0. Together with https://github.com/libp2p/rust-libp2p/issues/3844, this will allow us to move towards a much more aggressive closing of idle connections, together with a more ergonomic way of opting out of this behaviour.
Fixes#4121.
Pull-Request: #4161.
Previously, we used to race the two identify responses and assert the one that finished earlier. In practice, this didn't work but sometimes caused a timeout. See https://github.com/libp2p/rust-libp2p/actions/runs/4973490081/jobs/8899378998#step:7:98 for an example.
Interestingly enough, refactoring this test to always assert both responses reveals a bug! The memory transport by default behaves like TCP and allocates a new ephemeral port for an outgoing connection. I believe this was never hit because the first swarm would always receive its response first and win the race.
To assert this properly, we would have to implement port reuse for the memory transport which I think is unnecessary, hence I just commented out the assertion.
Pull-Request: #3924.
This patch refactors the identify tests to use `libp2p-swarm-test`. This allows us to delete quite a bit of code and makes several dev-dependencies obsolete.
The `correct_transfer` test is made obsolete by more precise assertions in the `periodic_identify` test. This allows us to remove the dependency on the `upgrade::{apply_inbound,apply_outbound}` functions.
Finally, we also fix a bug where the reported listen addresses to the other node could contain duplicates.
Related: #3748.
Pull-Request: #3851.
