[wallet] Restore confirmed/conflicted tx check in SubmitMemoryPoolAndRelay()

Restores the confirmed/conflicted tx check removed in
8753f5652b. There should be no external
behaviour change (these txs would not get accepted to the mempool
anyway), but not having the check in the wallet causes log spam.

Also adds a comment to ResentWalletTransactions() that
confirmed/conflicted tx check is done in SubmitMemoryPoolAndRelay().

src/wallet/wallet.cpp

@@ -2150,11 +2150,11 @@ void CWallet::ReacceptWalletTransactions(interfaces::Chain::Lock& locked_chain)
     for (const std::pair<const int64_t, CWalletTx*>& item : mapSorted) {
         CWalletTx& wtx = *(item.second);
         std::string unused_err_string;
-        wtx.SubmitMemoryPoolAndRelay(unused_err_string, false);
+        wtx.SubmitMemoryPoolAndRelay(unused_err_string, false, locked_chain);
     }
 }
 
-bool CWalletTx::SubmitMemoryPoolAndRelay(std::string& err_string, bool relay)
+bool CWalletTx::SubmitMemoryPoolAndRelay(std::string& err_string, bool relay, interfaces::Chain::Lock& locked_chain)
 {
     // Can't relay if wallet is not broadcasting
     if (!pwallet->GetBroadcastTransactions()) return false;
@@ -2163,6 +2163,8 @@ bool CWalletTx::SubmitMemoryPoolAndRelay(std::string& err_string, bool relay)
     // Don't try to submit coinbase transactions. These would fail anyway but would
     // cause log spam.
     if (IsCoinBase()) return false;
+    // Don't try to submit conflicted or confirmed transactions.
+    if (GetDepthInMainChain(locked_chain) != 0) return false;
 
     // Submit transaction to mempool for relay
     pwallet->WalletLogPrintf("Submitting wtx %s to mempool for relay\n", GetHash().ToString());
@@ -2377,11 +2379,12 @@ void CWallet::ResendWalletTransactions()
         // Relay transactions
         for (std::pair<const uint256, CWalletTx>& item : mapWallet) {
             CWalletTx& wtx = item.second;
-            // only rebroadcast unconfirmed txes older than 5 minutes before the
-            // last block was found
+            // Attempt to rebroadcast all txes more than 5 minutes older than
+            // the last block. SubmitMemoryPoolAndRelay() will not rebroadcast
+            // any confirmed or conflicting txs.
             if (wtx.nTimeReceived > m_best_block_time - 5 * 60) continue;
             std::string unused_err_string;
-            if (wtx.SubmitMemoryPoolAndRelay(unused_err_string, true)) ++submitted_tx_count;
+            if (wtx.SubmitMemoryPoolAndRelay(unused_err_string, true, *locked_chain)) ++submitted_tx_count;
         }
     } // locked_chain and cs_wallet
 
@@ -3326,7 +3329,7 @@ bool CWallet::CommitTransaction(CTransactionRef tx, mapValue_t mapValue, std::ve
         if (fBroadcastTransactions)
         {
             std::string err_string;
-            if (!wtx.SubmitMemoryPoolAndRelay(err_string, true)) {
+            if (!wtx.SubmitMemoryPoolAndRelay(err_string, true, *locked_chain)) {
                 WalletLogPrintf("CommitTransaction(): Transaction cannot be broadcast immediately, %s\n", err_string);
                 // TODO: if we expect the failure to be long term or permanent, instead delete wtx from the wallet and return failure.
             }

src/wallet/wallet.h

@@ -580,7 +580,7 @@ public:
     int64_t GetTxTime() const;
 
     // Pass this transaction to node for mempool insertion and relay to peers if flag set to true
-    bool SubmitMemoryPoolAndRelay(std::string& err_string, bool relay);
+    bool SubmitMemoryPoolAndRelay(std::string& err_string, bool relay, interfaces::Chain::Lock& locked_chain);
 
     // TODO: Remove "NO_THREAD_SAFETY_ANALYSIS" and replace it with the correct
     // annotation "EXCLUSIVE_LOCKS_REQUIRED(pwallet->cs_wallet)". The annotation