validation: when adding txs due to a block reorg, allow immediate relay

Author: ajtowns

src/validation.cpp

@@ -834,7 +834,10 @@ bool MemPoolAccept::PreChecks(ATMPArgs& args, Workspace& ws)
         }
     }
 
-    entry.reset(new CTxMemPoolEntry(ptx, ws.m_base_fees, nAcceptTime, m_active_chainstate.m_chain.Height(), m_pool.GetSequence(),
+    // Set entry_sequence to 0 when bypass_limits is used; this allows txs from a block
+    // reorg to be marked earlier than any child txs that were already in the mempool.
+    const uint64_t entry_sequence = bypass_limits ? 0 : m_pool.GetSequence();
+    entry.reset(new CTxMemPoolEntry(ptx, ws.m_base_fees, nAcceptTime, m_active_chainstate.m_chain.Height(), entry_sequence,
                                     fSpendsCoinbase, nSigOpsCost, lock_points.value()));
     ws.m_vsize = entry->GetTxSize();
 

src/validation.h

@@ -239,7 +239,8 @@ struct PackageMempoolAcceptResult
  * @param[in]  tx                 The transaction to submit for mempool acceptance.
  * @param[in]  accept_time        The timestamp for adding the transaction to the mempool.
  *                                It is also used to determine when the entry expires.
- * @param[in]  bypass_limits      When true, don't enforce mempool fee and capacity limits.
+ * @param[in]  bypass_limits      When true, don't enforce mempool fee and capacity limits,
+ *                                and set entry_sequence to zero.
  * @param[in]  test_accept        When true, run validation checks but don't submit to mempool.
  *
  * @returns a MempoolAcceptResult indicating whether the transaction was accepted/rejected with reason.