diff --git a/substrate/client/network/sync/src/lib.rs b/substrate/client/network/sync/src/lib.rs index 10eaa2450518e..0c8e8a104e2ae 100644 --- a/substrate/client/network/sync/src/lib.rs +++ b/substrate/client/network/sync/src/lib.rs @@ -3364,4 +3364,129 @@ mod test { pending_responses.remove(&peers[1]); assert_eq!(pending_responses.len(), 0); } + + /// The test demonstrates https://github.com/paritytech/polkadot-sdk/issues/2094. + /// TODO: convert it into desired behavior test once the issue is fixed (see inline comments). + /// The issue: we currently rely on block numbers instead of block hash + /// to download blocks from peers. As a result, we can end up with blocks + /// from different forks as shown by the test. + #[test] + #[should_panic] + fn request_across_forks() { + sp_tracing::try_init_simple(); + + let (_chain_sync_network_provider, chain_sync_network_handle) = + NetworkServiceProvider::new(); + let mut client = Arc::new(TestClientBuilder::new().build()); + let blocks = (0..100).map(|_| build_block(&mut client, None, false)).collect::>(); + + let fork_a_blocks = { + let mut client = Arc::new(TestClientBuilder::new().build()); + let mut fork_blocks = blocks[..] + .into_iter() + .inspect(|b| { + assert!(matches!(client.block(*b.header.parent_hash()), Ok(Some(_)))); + block_on(client.import(BlockOrigin::Own, (*b).clone())).unwrap() + }) + .cloned() + .collect::>(); + for _ in 0..10 { + fork_blocks.push(build_block(&mut client, None, false)); + } + fork_blocks + }; + + let fork_b_blocks = { + let mut client = Arc::new(TestClientBuilder::new().build()); + let mut fork_blocks = blocks[..] + .into_iter() + .inspect(|b| { + assert!(matches!(client.block(*b.header.parent_hash()), Ok(Some(_)))); + block_on(client.import(BlockOrigin::Own, (*b).clone())).unwrap() + }) + .cloned() + .collect::>(); + for _ in 0..10 { + fork_blocks.push(build_block(&mut client, None, true)); + } + fork_blocks + }; + + let mut sync = ChainSync::new( + SyncMode::Full, + client.clone(), + ProtocolName::from("test-block-announce-protocol"), + 5, + 64, + None, + chain_sync_network_handle, + ) + .unwrap(); + + // Add the peers, all at the common ancestor 100. + let common_block = blocks.last().unwrap(); + let peer_id1 = PeerId::random(); + sync.new_peer(peer_id1, common_block.hash(), *common_block.header().number()) + .unwrap(); + let peer_id2 = PeerId::random(); + sync.new_peer(peer_id2, common_block.hash(), *common_block.header().number()) + .unwrap(); + + // Peer 1 announces 107 from fork 1, 100-107 get downloaded. + { + let block = (&fork_a_blocks[106]).clone(); + let peer = peer_id1; + log::trace!(target: LOG_TARGET, "<1> {peer} announces from fork 1"); + send_block_announce(block.header().clone(), peer, &mut sync); + let request = get_block_request(&mut sync, FromBlock::Hash(block.hash()), 7, &peer); + let mut resp_blocks = fork_a_blocks[100_usize..107_usize].to_vec(); + resp_blocks.reverse(); + let response = create_block_response(resp_blocks.clone()); + let res = sync.on_block_data(&peer, Some(request), response).unwrap(); + assert!(matches!( + res, + OnBlockData::Import(ImportBlocksAction{ origin: _, blocks }) if blocks.len() == 7_usize + ),); + assert_eq!(sync.best_queued_number, 107); + assert_eq!(sync.best_queued_hash, block.hash()); + assert!(sync.is_known(&block.header.parent_hash())); + } + + // Peer 2 also announces 107 from fork 1. + { + let prev_best_number = sync.best_queued_number; + let prev_best_hash = sync.best_queued_hash; + let peer = peer_id2; + log::trace!(target: LOG_TARGET, "<2> {peer} announces from fork 1"); + for i in 100..107 { + let block = (&fork_a_blocks[i]).clone(); + send_block_announce(block.header().clone(), peer, &mut sync); + assert!(sync.block_requests().is_empty()); + } + assert_eq!(sync.best_queued_number, prev_best_number); + assert_eq!(sync.best_queued_hash, prev_best_hash); + } + + // Peer 2 undergoes reorg, announces 108 from fork 2, gets downloaded even though we + // don't have the parent from fork 2. + { + let block = (&fork_b_blocks[107]).clone(); + let peer = peer_id2; + log::trace!(target: LOG_TARGET, "<3> {peer} announces from fork 2"); + send_block_announce(block.header().clone(), peer, &mut sync); + // TODO: when the issue is fixed, this test can be changed to test the + // expected behavior instead. The needed changes would be: + // 1. Remove the `#[should_panic]` directive + // 2. These should be changed to check that sync.block_requests().is_empty(), after the + // block is announced. + let request = get_block_request(&mut sync, FromBlock::Hash(block.hash()), 1, &peer); + let response = create_block_response(vec![block.clone()]); + let res = sync.on_block_data(&peer, Some(request), response).unwrap(); + assert!(matches!( + res, + OnBlockData::Import(ImportBlocksAction{ origin: _, blocks }) if blocks.len() == 1_usize + ),); + assert!(sync.is_known(&block.header.parent_hash())); + } + } }