Move recentRejects initialization to top of InitBlockIndex

This avoids that premature return in the condition that a new chain is initialized
results in NULL pointer errors due to recentReject not being constructed.

Also add assertions where it is used.

src/main.cpp

@@ -4710,6 +4710,10 @@ bool LoadBlockIndex(std::string& strError)
 bool InitBlockIndex()
 {
     LOCK(cs_main);
+
+    // Initialize global variables that cannot be constructed at startup.
+    recentRejects.reset(new CRollingBloomFilter(120000, 0.000001));
+
     // Check whether we're already initialized
     if (chainActive.Genesis() != NULL)
         return true;
@@ -4741,9 +4745,6 @@ bool InitBlockIndex()
         }
     }
 
-    // Initialize global variables that cannot be constructed at startup.
-    recentRejects.reset(new CRollingBloomFilter(120000, 0.000001));
-
     return true;
 }
 
@@ -5033,6 +5034,7 @@ bool static AlreadyHave(const CInv& inv)
 {
     switch (inv.type) {
     case MSG_TX: {
+        assert(recentRejects);
         if (chainActive.Tip()->GetBlockHash() != hashRecentRejectsChainTip) {
             // If the chain tip has changed previously rejected transactions
             // might be now valid, e.g. due to a nLockTime'd tx becoming valid,
@@ -5773,6 +5775,7 @@ bool static ProcessMessage(CNode* pfrom, std::string strCommand, CDataStream& vR
                         // Probably non-standard or insufficient fee/priority
                         LogPrint(BCLog::MEMPOOL, "   removed orphan tx %s\n", orphanHash.ToString());
                         vEraseQueue.push_back(orphanHash);
+                        assert(recentRejects);
                         recentRejects->insert(orphanHash);
                     }
                     mempool.check(pcoinsTip);
@@ -5802,6 +5805,7 @@ bool static ProcessMessage(CNode* pfrom, std::string strCommand, CDataStream& vR
             // already in the mempool; if the tx isn't in the mempool that
             // means it was rejected and we shouldn't ask for it again.
             if (!mempool.exists(tx.GetHash())) {
+                assert(recentRejects);
                 recentRejects->insert(tx.GetHash());
             }
             if (pfrom->fWhitelisted) {