RPC port default behavior changed

[BulatSaif]

After #2417 merged the default behavior for JSON-RPC changed:

Old behavior:

Node	Port
Relaychain	9945
Parachain	9944

Example:

docker run -it paritypr/polkadot-parachain-debug:v0.9.400-269fb073 --unsafe-rpc-external --unsafe-ws-external --rpc-cors=all --rpc-methods=unsafe --tmp -- --chain rococo  | grep JSON-RPC
2023-05-05 13:52:43 [Relaychain] Running JSON-RPC HTTP server: addr=127.0.0.1:9934, allowed origins=["http://localhost:*", "http://127.0.0.1:*", "https://localhost:*", "https://127.0.0.1:*", "https://polkadot.js.org"]    
2023-05-05 13:52:43 [Relaychain] Running JSON-RPC WS server: addr=127.0.0.1:9945, allowed origins=["http://localhost:*", "http://127.0.0.1:*", "https://localhost:*", "https://127.0.0.1:*", "https://polkadot.js.org"]    
2023-05-05 13:52:44 [Parachain] Running JSON-RPC HTTP server: addr=0.0.0.0:9933, allowed origins=["*"]    
2023-05-05 13:52:44 [Parachain] Running JSON-RPC WS server: addr=0.0.0.0:9944, allowed origins=["*"]  

New behavior:

Node	Port
Relaychain	9944
Parachain	Random

docker run -it paritypr/polkadot-parachain-debug:master-ab7ce3bc --unsafe-rpc-external  --rpc-cors=all --rpc-methods=unsafe --tmp -- --chain rococo  | grep JSON-RPC
2023-05-05 13:53:27 [Relaychain] Running JSON-RPC server: addr=127.0.0.1:9944, allowed origins=["http://localhost:*", "http://127.0.0.1:*", "https://localhost:*", "https://127.0.0.1:*", "https://polkadot.js.org"]    
2023-05-05 13:53:27 [Parachain] Running JSON-RPC server: addr=0.0.0.0:45755, allowed origins=["*"] 

Expected behavior:

Node	Port
Relaychain	9945
Parachain	9944

[Relaychain] Running JSON-RPC server: addr=127.0.0.1:9945, allowed origins=["http://localhost:*", "http://127.0.0.1:*", "https://localhost:*", "https://127.0.0.1:*", "https://polkadot.js.org"]    
[Parachain] Running JSON-RPC server: addr=0.0.0.0:9944, allowed origins=["*"] 

[PierreBesson]

IMO this is really dangerous for Parachain RPC node operators who have not have set an explicit port in flags (ie. most users) as this will direct RPC traffic to the Relay-chain node. It will also be hard to troubleshoot for them as it will initially appear to work but return the wrong data.

Please hold off the release until it is fixed.

[niklasad1]

hmm, weird lemme have a look at it.

EDIT:
Ok, the substrate PR changed the default value for the port from Option<Port> to Port so the rpc_listen_port override isn't used because it's already a value in there.

So, either change to port to Option<port> in substrate or just override it in cumulus.