refactor: log nEvicted message in LimitOrphans then return void

`LimitOrphans()` can log expired tx and it should log evicted tx as well
instead of returning the number for caller to print the message.
Since `LimitOrphans()` now return void, the redundant assertion check in
fuzz test is also removed.

Author: chinggg

src/net_processing.cpp

@@ -3630,10 +3630,7 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
 
                 // DoS prevention: do not allow m_orphanage to grow unbounded (see CVE-2012-3789)
                 unsigned int nMaxOrphanTx = (unsigned int)std::max((int64_t)0, gArgs.GetIntArg("-maxorphantx", DEFAULT_MAX_ORPHAN_TRANSACTIONS));
-                unsigned int nEvicted = m_orphanage.LimitOrphans(nMaxOrphanTx);
-                if (nEvicted > 0) {
-                    LogPrint(BCLog::MEMPOOL, "orphanage overflow, removed %u tx\n", nEvicted);
-                }
+                m_orphanage.LimitOrphans(nMaxOrphanTx);
             } else {
                 LogPrint(BCLog::MEMPOOL, "not keeping orphan with rejected parents %s\n",tx.GetHash().ToString());
                 // We will continue to reject this tx since it has rejected

src/test/fuzz/txorphan.cpp

@@ -138,10 +138,8 @@ FUZZ_TARGET_INIT(txorphan, initialize_orphanage)
                 [&] {
                     // test mocktime and expiry
                     SetMockTime(ConsumeTime(fuzzed_data_provider));
-                    auto size_before = orphanage.Size();
                     auto limit = fuzzed_data_provider.ConsumeIntegral<unsigned int>();
-                    auto n_evicted = WITH_LOCK(g_cs_orphans, return orphanage.LimitOrphans(limit));
-                    Assert(size_before - n_evicted <= limit);
+                    WITH_LOCK(g_cs_orphans, orphanage.LimitOrphans(limit));
                     Assert(orphanage.Size() <= limit);
                 });
         }

src/txorphanage.cpp

@@ -102,7 +102,7 @@ void TxOrphanage::EraseForPeer(NodeId peer)
     if (nErased > 0) LogPrint(BCLog::MEMPOOL, "Erased %d orphan tx from peer=%d\n", nErased, peer);
 }
 
-unsigned int TxOrphanage::LimitOrphans(unsigned int max_orphans)
+void TxOrphanage::LimitOrphans(unsigned int max_orphans)
 {
     AssertLockHeld(g_cs_orphans);
 
@@ -135,7 +135,7 @@ unsigned int TxOrphanage::LimitOrphans(unsigned int max_orphans)
         EraseTx(m_orphan_list[randompos]->first);
         ++nEvicted;
     }
-    return nEvicted;
+    if (nEvicted > 0) LogPrint(BCLog::MEMPOOL, "orphanage overflow, removed %u tx\n", nEvicted);
 }
 
 void TxOrphanage::AddChildrenToWorkSet(const CTransaction& tx, std::set<uint256>& orphan_work_set) const

src/txorphanage.h

@@ -41,7 +41,7 @@ class TxOrphanage {
     void EraseForBlock(const CBlock& block) LOCKS_EXCLUDED(::g_cs_orphans);
 
     /** Limit the orphanage to the given maximum */
-    unsigned int LimitOrphans(unsigned int max_orphans) EXCLUSIVE_LOCKS_REQUIRED(g_cs_orphans);
+    void LimitOrphans(unsigned int max_orphans) EXCLUSIVE_LOCKS_REQUIRED(g_cs_orphans);
 
     /** Add any orphans that list a particular tx as a parent into a peer's work set
      * (ie orphans that may have found their final missing parent, and so should be reconsidered for the mempool) */