Wallet can now recover on startup

Stratis.Bitcoin.IntegrationTests/WalletTests.cs

@@ -258,5 +258,40 @@ public void WalletCanCatchupWithBestChain()
                 TestHelper.WaitLoop(() => TestHelper.IsNodeSynced(stratisminer));
             }
         }
+
+        [Fact]
+        public void WalletCanRecoverOnStartup()
+        {
+            using (NodeBuilder builder = NodeBuilder.Create())
+            {
+                var stratisNodeSync = builder.CreateStratisNode();
+                builder.StartAll();
+                stratisNodeSync.NotInIBD();
+
+                // get a key from the wallet
+                var mnemonic = stratisNodeSync.FullNode.WalletManager.CreateWallet("123456", "mywallet");
+                Assert.Equal(12, mnemonic.Words.Length);
+                var addr = stratisNodeSync.FullNode.WalletManager.GetUnusedAddress("mywallet", "account 0");
+                var key = stratisNodeSync.FullNode.WalletManager.GetKeyForAddress("123456", addr).PrivateKey;
+
+                stratisNodeSync.SetDummyMinerSecret(key.GetBitcoinSecret(stratisNodeSync.FullNode.Network));
+                stratisNodeSync.GenerateStratis(10);
+                TestHelper.WaitLoop(() => TestHelper.IsNodeSynced(stratisNodeSync));
+
+                // set the tip of best chain some blocks in the apst
+                stratisNodeSync.FullNode.Chain.SetTip(stratisNodeSync.FullNode.Chain.GetBlock(stratisNodeSync.FullNode.Chain.Height - 5));
+
+                // stop the node it will persist the chain with the reset tip
+                stratisNodeSync.FullNode.Stop();
+
+                var newNodeInstance = builder.CloneStratisNode(stratisNodeSync);
+
+                // load the node, this should hit the block store recover code
+                newNodeInstance.Start();
+
+                // check that store recovered to be the same as the best chain.
+                Assert.Equal(newNodeInstance.FullNode.Chain.Tip.HashBlock, newNodeInstance.FullNode.WalletManager.WalletTipHash);
+            }
+        }
     }
 }

Stratis.Bitcoin/Wallet/Wallet.cs

@@ -32,6 +32,12 @@ public class Wallet
         [JsonConverter(typeof(ByteArrayConverter))]
         public byte[] ChainCode { get; set; }
 
+        /// <summary>
+        /// Gets or sets the merkle path.
+        /// </summary>
+        [JsonProperty(PropertyName = "blockLocator", ItemConverterType = typeof(UInt256JsonConverter))]
+        public ICollection<uint256> BlockLocator { get; set; }
+
         /// <summary>
         /// The network this wallet is for.
         /// </summary>

Stratis.Bitcoin/Wallet/WalletManager.cs

@@ -882,6 +882,10 @@ public void UpdateLastBlockSyncedHeight(ChainedBlock chainedBlock)
         /// <inheritdoc />
         public void UpdateLastBlockSyncedHeight(Wallet wallet, ChainedBlock chainedBlock)
         {
+            // the block locator will help when the wallet 
+            // needs to rewind this will be used to find the fork 
+            wallet.BlockLocator = chainedBlock.GetLocator().Blocks;
+
             // update the wallets with the last processed block height
             foreach (var accountRoot in wallet.AccountsRoot.Where(a => a.CoinType == this.coinType))
             {

Stratis.Bitcoin/Wallet/WalletSyncManager.cs

@@ -49,16 +49,22 @@ public virtual Task Initialize()
 
             this.walletTip = this.chain.GetBlock(this.walletManager.WalletTipHash);
             if (this.walletTip == null)
-                throw new WalletException("Wallet tip was not found in the best chain, rescan the wallet");
-
-            // offline reorg is extreamly reare it will 
-            // only happen if the node crashes during a reorg
-
-            //var blockstoremove = new List<uint256>();
-            //var locators = this.walletManager.Wallets.First().BlockLocator;
-            //BlockLocator blockLocator = new BlockLocator { Blocks = locators.ToList() };
-            //var fork = this.chain.FindFork(blockLocator);
-            //this.walletManager.RemoveBlocks(fork);
+            {
+                // the wallet tip was not found int he main chain
+                // this can happen if the node crashes unexpecdidely
+                // reo reconver we need to find the first common fork 
+                // with the best chain, as the wallet does not have a  
+                // list of chain headers we use a BlockLocator and persist 
+                // tha tin the wallet, the block locator will help finding 
+                // a common form and bringing the wallet back to a good 
+                // state (behind the best chain)
+
+                var locators = this.walletManager.Wallets.First().BlockLocator;
+                BlockLocator blockLocator = new BlockLocator { Blocks = locators.ToList() };
+                var fork = this.chain.FindFork(blockLocator);
+                this.walletManager.RemoveBlocks(fork);
+                this.walletManager.WalletTipHash = fork.HashBlock;
+            }
 
             return Task.CompletedTask;
         }
@@ -100,9 +106,23 @@ public virtual void ProcessBlock(Block block)
                             // will stop til the wallet is up to date.
 
                             next = this.chain.GetBlock(next.Height +1);
-                            var nextblock = this.blockStoreCache.GetBlockAsync(next.HashBlock).GetAwaiter().GetResult();
-                            if(nextblock == null)
-                                return; // temporary to allow wallet ot recover when store is behind
+                            Block nextblock = null;
+                            while (true) //replace with cancelation token
+                            {
+                                nextblock = this.blockStoreCache.GetBlockAsync(next.HashBlock).GetAwaiter().GetResult();
+                                if (nextblock == null)
+                                {
+                                    // really ugly hack to let store catch up
+                                    // this will block the entire consensus pulling
+                                    this.logger.LogInformation("Wallet is behind the best chain and the next block is not found in store");
+                                    Thread.Sleep(100);
+                                    continue;
+                                }
+
+                                break;
+                            }
+
+                            this.walletTip = next;
                             this.walletManager.ProcessBlock(nextblock, next);
                         }
                     }