Merge #15728: [wallet] Refactor relay transactions

7a9046e48 [wallet] Refactor CWalletTx::RelayWalletTransaction() (John Newbery)

Pull request description:

  Refactor `CWalletTx::RelayWalletTransaction()` function.

  This was a suggestion from the wallet-node separation PR: https://github.com/bitcoin/bitcoin/pull/15288#discussion_r256036330, which we deferred until after the main PR was merged.

  There are also makes two minor behavior changes:

  - no longer assert if fBroadcastTransactions is false. Just return false from the function.
  - no longer print the relay message if p2pEnabled is set to false (since the transaction is not actually relayed).

ACKs for commit 7a9046:
  promag:
    utACK 7a9046e48d0aac35e8e6a3dd315aa98a207bebfe.
  MeshCollider:
    utACK https://github.com/bitcoin/bitcoin/pull/15728/commits/7a9046e48d0aac35e8e6a3dd315aa98a207bebfe
  ryanofsky:
    utACK 7a9046e48d0aac35e8e6a3dd315aa98a207bebfe. No changes at all, just rebase after base PR #15632 was merged

Tree-SHA512: 2ae6214cfadd917a1b3a892c4277e5e57c3eb791e17f67511470e6fbc634d19356554b9f9c55af6b779fdef821914aad59b7cc9e6c13ece145df003bf507d486

2 files changed, 20 insertions, 15 deletions

diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 2ef6850a2e..743704d5f8 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -1900,20 +1900,25 @@ void CWallet::ReacceptWalletTransactions(interfaces::Chain::Lock& locked_chain)
 
 bool CWalletTx::RelayWalletTransaction(interfaces::Chain::Lock& locked_chain)
 {
-    assert(pwallet->GetBroadcastTransactions());
-    if (!IsCoinBase() && !isAbandoned() && GetDepthInMainChain(locked_chain) == 0)
-    {
-        CValidationState state;
-        /* GetDepthInMainChain already catches known conflicts. */
-        if (InMempool() || AcceptToMemoryPool(locked_chain, state)) {
-            pwallet->WalletLogPrintf("Relaying wtx %s\n", GetHash().ToString());
-            if (pwallet->chain().p2pEnabled()) {
-                pwallet->chain().relayTransaction(GetHash());
-                return true;
-            }
-        }
-    }
-    return false;
+    // Can't relay if wallet is not broadcasting
+    if (!pwallet->GetBroadcastTransactions()) return false;
+    // Don't relay coinbase transactions outside blocks
+    if (IsCoinBase()) return false;
+    // Don't relay abandoned transactions
+    if (isAbandoned()) return false;
+    // Don't relay conflicted or already confirmed transactions
+    if (GetDepthInMainChain(locked_chain) != 0) return false;
+    // Don't relay transactions that aren't accepted to the mempool
+    CValidationState unused_state;
+    if (!InMempool() && !AcceptToMemoryPool(locked_chain, unused_state)) return false;
+    // Don't try to relay if the node is not connected to the p2p network
+    if (!pwallet->chain().p2pEnabled()) return false;
+
+    // Try to relay the transaction
+    pwallet->WalletLogPrintf("Relaying wtx %s\n", GetHash().ToString());
+    pwallet->chain().relayTransaction(GetHash());
+
+    return true;
 }
 
 std::set<uint256> CWalletTx::GetConflicts() const
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index cefdf479c6..36c0e160dd 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -515,7 +515,7 @@ public:
 
     int64_t GetTxTime() const;
 
-    // RelayWalletTransaction may only be called if fBroadcastTransactions!
+    // Pass this transaction to the node to relay to its peers
     bool RelayWalletTransaction(interfaces::Chain::Lock& locked_chain);
 
     /** Pass this transaction to the mempool. Fails if absolute fee exceeds absurd fee. */