Merge pull request #905 from earlbread/fix-demand-block-hashes

Demand block hashes from branch point
planetarium · Jun 12, 2020 · f4c1068 · f4c1068
2 parents 3455740 + bc6a641
commit f4c1068
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diff --git a/CHANGES.md b/CHANGES.md
@@ -6,6 +6,11 @@ Version 0.9.5
 
 To be released.
 
+ -  Fixed a bug that had not properly received block hashes after the chain had reorged.
+    [[#880], [#905]]
+
+[#905]: https://github.com/planetarium/libplanet/pull/905
+
 
 Version 0.9.4
 --------------

diff --git a/Libplanet.Tests/Net/SwarmTest.Preload.cs b/Libplanet.Tests/Net/SwarmTest.Preload.cs
@@ -1208,6 +1208,51 @@ public async Task GetDemandBlockHashes()
             Assert.Equal(expectedBlocks, demands);
         }
 
+        [Fact]
+        public async Task PreloadAfterReorg()
+        {
+            Swarm<DumbAction> minerSwarm = _swarms[0];
+            Swarm<DumbAction> receiverSwarm = _swarms[1];
+
+            BlockChain<DumbAction> minerChain = _blockchains[0];
+            BlockChain<DumbAction> receiverChain = _blockchains[1];
+
+            foreach (int i in Enumerable.Range(0, 25))
+            {
+                Block<DumbAction> block = await minerChain.MineBlock(_fx1.Address1);
+                receiverChain.Append(block);
+            }
+
+            var receiverForked = receiverChain.Fork(receiverChain[5].Hash);
+            foreach (int i in Enumerable.Range(0, 20))
+            {
+                await receiverForked.MineBlock(_fx1.Address1);
+            }
+
+            receiverChain.Swap(receiverForked, false);
+
+            foreach (int i in Enumerable.Range(0, 1))
+            {
+                await minerChain.MineBlock(_fx1.Address1);
+            }
+
+            minerSwarm.FindNextHashesChunkSize = 1;
+            try
+            {
+                await StartAsync(minerSwarm);
+                await receiverSwarm.AddPeersAsync(new[] { minerSwarm.AsPeer }, null);
+                await receiverSwarm.PreloadAsync(
+                    trustedStateValidators: new[] { minerSwarm.Address }.ToImmutableHashSet()
+                );
+            }
+            finally
+            {
+                await StopAsync(minerSwarm);
+            }
+
+            Assert.Equal(minerChain.BlockHashes, receiverChain.BlockHashes);
+        }
+
         [Fact(Timeout = Timeout)]
         public async Task GetDemandBlockHashesDuringReorg()
         {

diff --git a/Libplanet/Net/Swarm.cs b/Libplanet/Net/Swarm.cs
@@ -1055,6 +1055,9 @@ [EnumeratorCancellation] CancellationToken cancellationToken
                 i++;
                 long peerIndex = peerHeight ?? -1;
 
+                long branchIndex = -1;
+                HashDigest<SHA256> branchPoint = default;
+
                 // FIXME: The following condition should be fixed together when the issue #459 is
                 // fixed.  https://github.com/planetarium/libplanet/issues/459
                 if (peer is null || currentTipIndex >= peerIndex)
@@ -1092,6 +1095,14 @@ [EnumeratorCancellation] CancellationToken cancellationToken
 
                         IAsyncEnumerable<Tuple<long, HashDigest<SHA256>>> blockHashes =
                             GetBlockHashes(peer, locator, null, cancellationToken);
+
+                        if (branchIndex == -1 &&
+                            await blockHashes.FirstAsync(cancellationToken) is { } t)
+                        {
+                            t.Deconstruct(out branchIndex, out branchPoint);
+                            totalBlocksToDownload = peerIndex - branchIndex;
+                        }
+
                         await foreach (Tuple<long, HashDigest<SHA256>> pair in blockHashes)
                         {
                             pair.Deconstruct(out long dlIndex, out HashDigest<SHA256> dlHash);
@@ -1102,7 +1113,7 @@ [EnumeratorCancellation] CancellationToken cancellationToken
                                 dlHash
                             );
 
-                            if (downloaded.Contains(dlHash) || blockChain.ContainsBlock(dlHash))
+                            if (downloaded.Contains(dlHash) || dlHash.Equals(branchPoint))
                             {
                                 continue;
                             }