Encapsulate tx status in a Confirmation struct

Instead of relying on combination of hashBlock and nIndex
values to manage tx in its lifecycle, we introduce 4
status : CONFIRMED, UNCONFIRMED, CONFLICTED, ABANDONED.

hashBlock and nIndex magic values should only be used at
serialization/deserialization for backward-compatibility.

At block disconnection, we know flag txn as UNCONFIRMED where
previously they kept their states until being override by a
block connection or abandontransaction call. This is a change
in behavior for which user may have to call abandon twice
if transaction is disconnected and not accepted back in the mempool.

We assert status transitioning right in AddToWallet. Doing so
flagged a misbehavior in ComputeTimeSmart unit test where same
tx is confirmed twice in different block. To avoid inconsistencies
we unconfirmed tx before new connection in different block. We
also remove a cs_main lock in test, as AddToWallet and its
callees don't rely on locked chain.

1 files changed, 41 insertions, 41 deletions

diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 03acf23508..098f7990ad 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -1118,22 +1118,14 @@ bool CWallet::AddToWallet(const CWalletTx& wtxIn, bool fFlushOnClose)
     bool fUpdated = false;
     if (!fInsertedNew)
     {
-        // Merge
-        if (!wtxIn.hashUnset() && wtxIn.hashBlock != wtx.hashBlock)
-        {
-            wtx.hashBlock = wtxIn.hashBlock;
-            fUpdated = true;
-        }
-        // If no longer abandoned, update
-        if (wtxIn.hashBlock.IsNull() && wtx.isAbandoned())
-        {
-            wtx.hashBlock = wtxIn.hashBlock;
-            fUpdated = true;
-        }
-        if (wtxIn.nIndex != -1 && (wtxIn.nIndex != wtx.nIndex))
-        {
-            wtx.nIndex = wtxIn.nIndex;
+        if (wtxIn.m_confirm.status != wtx.m_confirm.status) {
+            wtx.m_confirm.status = wtxIn.m_confirm.status;
+            wtx.m_confirm.nIndex = wtxIn.m_confirm.nIndex;
+            wtx.m_confirm.hashBlock = wtxIn.m_confirm.hashBlock;
             fUpdated = true;
+        } else {
+            assert(wtx.m_confirm.nIndex == wtxIn.m_confirm.nIndex);
+            assert(wtx.m_confirm.hashBlock == wtxIn.m_confirm.hashBlock);
         }
         if (wtxIn.fFromMe && wtxIn.fFromMe != wtx.fFromMe)
         {
@@ -1194,14 +1186,14 @@ void CWallet::LoadToWallet(const CWalletTx& wtxIn)
         auto it = mapWallet.find(txin.prevout.hash);
         if (it != mapWallet.end()) {
             CWalletTx& prevtx = it->second;
-            if (prevtx.nIndex == -1 && !prevtx.hashUnset()) {
-                MarkConflicted(prevtx.hashBlock, wtx.GetHash());
+            if (prevtx.isConflicted()) {
+                MarkConflicted(prevtx.m_confirm.hashBlock, wtx.GetHash());
             }
         }
     }
 }
 
-bool CWallet::AddToWalletIfInvolvingMe(const CTransactionRef& ptx, const uint256& block_hash, int posInBlock, bool fUpdate)
+bool CWallet::AddToWalletIfInvolvingMe(const CTransactionRef& ptx, CWalletTx::Status status, const uint256& block_hash, int posInBlock, bool fUpdate)
 {
     const CTransaction& tx = *ptx;
     {
@@ -1248,9 +1240,9 @@ bool CWallet::AddToWalletIfInvolvingMe(const CTransactionRef& ptx, const uint256
 
             CWalletTx wtx(this, ptx);
 
-            // Get merkle branch if transaction was found in a block
-            if (!block_hash.IsNull())
-                wtx.SetMerkleBranch(block_hash, posInBlock);
+            // Block disconnection override an abandoned tx as unconfirmed
+            // which means user may have to call abandontransaction again
+            wtx.SetConf(status, block_hash, posInBlock);
 
             return AddToWallet(wtx, false);
         }
@@ -1310,7 +1302,7 @@ bool CWallet::AbandonTransaction(interfaces::Chain::Lock& locked_chain, const ui
         if (currentconfirm == 0 && !wtx.isAbandoned()) {
             // If the orig tx was not in block/mempool, none of its spends can be in mempool
             assert(!wtx.InMempool());
-            wtx.nIndex = -1;
+            wtx.m_confirm.nIndex = 0;
             wtx.setAbandoned();
             wtx.MarkDirty();
             batch.WriteTx(wtx);
@@ -1364,8 +1356,9 @@ void CWallet::MarkConflicted(const uint256& hashBlock, const uint256& hashTx)
         if (conflictconfirms < currentconfirm) {
             // Block is 'more conflicted' than current confirm; update.
             // Mark transaction as conflicted with this block.
-            wtx.nIndex = -1;
-            wtx.hashBlock = hashBlock;
+            wtx.m_confirm.nIndex = 0;
+            wtx.m_confirm.hashBlock = hashBlock;
+            wtx.setConflicted();
             wtx.MarkDirty();
             batch.WriteTx(wtx);
             // Iterate over all its outputs, and mark transactions in the wallet that spend them conflicted too
@@ -1383,8 +1376,9 @@ void CWallet::MarkConflicted(const uint256& hashBlock, const uint256& hashTx)
     }
 }
 
-void CWallet::SyncTransaction(const CTransactionRef& ptx, const uint256& block_hash, int posInBlock, bool update_tx) {
-    if (!AddToWalletIfInvolvingMe(ptx, block_hash, posInBlock, update_tx))
+void CWallet::SyncTransaction(const CTransactionRef& ptx, CWalletTx::Status status, const uint256& block_hash, int posInBlock, bool update_tx)
+{
+    if (!AddToWalletIfInvolvingMe(ptx, status, block_hash, posInBlock, update_tx))
         return; // Not one of ours
 
     // If a transaction changes 'conflicted' state, that changes the balance
@@ -1396,7 +1390,7 @@ void CWallet::SyncTransaction(const CTransactionRef& ptx, const uint256& block_h
 void CWallet::TransactionAddedToMempool(const CTransactionRef& ptx) {
     auto locked_chain = chain().lock();
     LOCK(cs_wallet);
-    SyncTransaction(ptx, {} /* block hash */, 0 /* position in block */);
+    SyncTransaction(ptx, CWalletTx::Status::UNCONFIRMED, {} /* block hash */, 0 /* position in block */);
 
     auto it = mapWallet.find(ptx->GetHash());
     if (it != mapWallet.end()) {
@@ -1425,11 +1419,11 @@ void CWallet::BlockConnected(const CBlock& block, const std::vector<CTransaction
     // the notification that the conflicted transaction was evicted.
 
     for (const CTransactionRef& ptx : vtxConflicted) {
-        SyncTransaction(ptx, {} /* block hash */, 0 /* position in block */);
+        SyncTransaction(ptx, CWalletTx::Status::CONFLICTED, {} /* block hash */, 0 /* position in block */);
         TransactionRemovedFromMempool(ptx);
     }
     for (size_t i = 0; i < block.vtx.size(); i++) {
-        SyncTransaction(block.vtx[i], block_hash, i);
+        SyncTransaction(block.vtx[i], CWalletTx::Status::CONFIRMED, block_hash, i);
         TransactionRemovedFromMempool(block.vtx[i]);
     }
 
@@ -1440,8 +1434,12 @@ void CWallet::BlockDisconnected(const CBlock& block) {
     auto locked_chain = chain().lock();
     LOCK(cs_wallet);
 
+    // At block disconnection, this will change an abandoned transaction to
+    // be unconfirmed, whether or not the transaction is added back to the mempool.
+    // User may have to call abandontransaction again. It may be addressed in the
+    // future with a stickier abandoned state or even removing abandontransaction call.
     for (const CTransactionRef& ptx : block.vtx) {
-        SyncTransaction(ptx, {} /* block hash */, 0 /* position in block */);
+        SyncTransaction(ptx, CWalletTx::Status::UNCONFIRMED, {} /* block hash */, 0 /* position in block */);
     }
 }
 
@@ -2078,7 +2076,7 @@ CWallet::ScanResult CWallet::ScanForWalletTransactions(const uint256& start_bloc
                 break;
             }
             for (size_t posInBlock = 0; posInBlock < block.vtx.size(); ++posInBlock) {
-                SyncTransaction(block.vtx[posInBlock], block_hash, posInBlock, fUpdate);
+                SyncTransaction(block.vtx[posInBlock], CWalletTx::Status::CONFIRMED, block_hash, posInBlock, fUpdate);
             }
             // scan succeeded, record block as most recent successfully scanned
             result.last_scanned_block = block_hash;
@@ -4050,7 +4048,7 @@ void CWallet::GetKeyBirthTimes(interfaces::Chain::Lock& locked_chain, std::map<C
     for (const auto& entry : mapWallet) {
         // iterate over all wallet transactions...
         const CWalletTx &wtx = entry.second;
-        if (Optional<int> height = locked_chain.getBlockHeight(wtx.hashBlock)) {
+        if (Optional<int> height = locked_chain.getBlockHeight(wtx.m_confirm.hashBlock)) {
             // ... which are already in a block
             for (const CTxOut &txout : wtx.tx->vout) {
                 // iterate over all their outputs
@@ -4093,9 +4091,9 @@ void CWallet::GetKeyBirthTimes(interfaces::Chain::Lock& locked_chain, std::map<C
 unsigned int CWallet::ComputeTimeSmart(const CWalletTx& wtx) const
 {
     unsigned int nTimeSmart = wtx.nTimeReceived;
-    if (!wtx.hashUnset()) {
+    if (!wtx.isUnconfirmed() && !wtx.isAbandoned()) {
         int64_t blocktime;
-        if (chain().findBlock(wtx.hashBlock, nullptr /* block */, &blocktime)) {
+        if (chain().findBlock(wtx.m_confirm.hashBlock, nullptr /* block */, &blocktime)) {
             int64_t latestNow = wtx.nTimeReceived;
             int64_t latestEntry = 0;
 
@@ -4123,7 +4121,7 @@ unsigned int CWallet::ComputeTimeSmart(const CWalletTx& wtx) const
 
             nTimeSmart = std::max(latestEntry, std::min(blocktime, latestNow));
         } else {
-            WalletLogPrintf("%s: found %s in block %s not in index\n", __func__, wtx.GetHash().ToString(), wtx.hashBlock.ToString());
+            WalletLogPrintf("%s: found %s in block %s not in index\n", __func__, wtx.GetHash().ToString(), wtx.m_confirm.hashBlock.ToString());
         }
     }
     return nTimeSmart;
@@ -4634,21 +4632,23 @@ CKeyPool::CKeyPool(const CPubKey& vchPubKeyIn, bool internalIn)
     m_pre_split = false;
 }
 
-void CWalletTx::SetMerkleBranch(const uint256& block_hash, int posInBlock)
+void CWalletTx::SetConf(Status status, const uint256& block_hash, int posInBlock)
 {
+    // Update tx status
+    m_confirm.status = status;
+
     // Update the tx's hashBlock
-    hashBlock = block_hash;
+    m_confirm.hashBlock = block_hash;
 
     // set the position of the transaction in the block
-    nIndex = posInBlock;
+    m_confirm.nIndex = posInBlock;
 }
 
 int CWalletTx::GetDepthInMainChain(interfaces::Chain::Lock& locked_chain) const
 {
-    if (hashUnset())
-        return 0;
+    if (isUnconfirmed() || isAbandoned()) return 0;
 
-    return locked_chain.getBlockDepth(hashBlock) * (nIndex == -1 ? -1 : 1);
+    return locked_chain.getBlockDepth(m_confirm.hashBlock) * (isConflicted() ? -1 : 1);
 }
 
 int CWalletTx::GetBlocksToMaturity(interfaces::Chain::Lock& locked_chain) const