Add additional block index consistency checks

This adds more tests to CheckBlockIndex:
- HAVE_DATA is true iff nTx > 0
- BLOCK_VALID_TRANSACTIONS is true iff nTx > 0
- BLOCK_VALID_TRANSACTIONS is true for a block and all parents iff
  nChainTx > 0

src/main.cpp

@@ -3248,6 +3248,7 @@ void static CheckBlockIndex()
     CBlockIndex* pindexFirstInvalid = NULL; // Oldest ancestor of pindex which is invalid.
     CBlockIndex* pindexFirstMissing = NULL; // Oldest ancestor of pindex which does not have BLOCK_HAVE_DATA.
     CBlockIndex* pindexFirstNotTreeValid = NULL; // Oldest ancestor of pindex which does not have BLOCK_VALID_TREE (regardless of being valid or not).
+    CBlockIndex* pindexFirstNotTransactionsValid = NULL; // Oldest ancestor of pindex which does not have BLOCK_VALID_TRANSACTIONS (regardless of being valid or not).
     CBlockIndex* pindexFirstNotChainValid = NULL; // Oldest ancestor of pindex which does not have BLOCK_VALID_CHAIN (regardless of being valid or not).
     CBlockIndex* pindexFirstNotScriptsValid = NULL; // Oldest ancestor of pindex which does not have BLOCK_VALID_SCRIPTS (regardless of being valid or not).
     while (pindex != NULL) {
@@ -3255,6 +3256,7 @@ void static CheckBlockIndex()
         if (pindexFirstInvalid == NULL && pindex->nStatus & BLOCK_FAILED_VALID) pindexFirstInvalid = pindex;
         if (pindexFirstMissing == NULL && !(pindex->nStatus & BLOCK_HAVE_DATA)) pindexFirstMissing = pindex;
         if (pindex->pprev != NULL && pindexFirstNotTreeValid == NULL && (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_TREE) pindexFirstNotTreeValid = pindex;
+        if (pindex->pprev != NULL && pindexFirstNotTransactionsValid == NULL && (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_TRANSACTIONS) pindexFirstNotTransactionsValid = pindex;
         if (pindex->pprev != NULL && pindexFirstNotChainValid == NULL && (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_CHAIN) pindexFirstNotChainValid = pindex;
         if (pindex->pprev != NULL && pindexFirstNotScriptsValid == NULL && (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_SCRIPTS) pindexFirstNotScriptsValid = pindex;
 
@@ -3264,7 +3266,12 @@ void static CheckBlockIndex()
             assert(pindex->GetBlockHash() == Params().HashGenesisBlock()); // Genesis block's hash must match.
             assert(pindex == chainActive.Genesis()); // The current active chain's genesis block must be this block.
         }
+        // HAVE_DATA is equivalent to VALID_TRANSACTIONS and equivalent to nTx > 0 (we stored the number of transactions in the block)
+        assert(!(pindex->nStatus & BLOCK_HAVE_DATA) == (pindex->nTx == 0));
+        assert(((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_TRANSACTIONS) == (pindex->nTx > 0));
+        // All parents having data is equivalent to all parents being VALID_TRANSACTIONS, which is equivalent to nChainTx being set.
         assert((pindexFirstMissing != NULL) == (pindex->nChainTx == 0)); // nChainTx == 0 is used to signal that all parent block's transaction data is available.
+        assert((pindexFirstNotTransactionsValid != NULL) == (pindex->nChainTx == 0));
         assert(pindex->nHeight == nHeight); // nHeight must be consistent.
         assert(pindex->pprev == NULL || pindex->nChainWork >= pindex->pprev->nChainWork); // For every block except the genesis block, the chainwork must be larger than the parent's.
         assert(nHeight < 2 || (pindex->pskip && (pindex->pskip->nHeight < nHeight))); // The pskip pointer must point back for all but the first 2 blocks.
@@ -3320,6 +3327,7 @@ void static CheckBlockIndex()
             if (pindex == pindexFirstInvalid) pindexFirstInvalid = NULL;
             if (pindex == pindexFirstMissing) pindexFirstMissing = NULL;
             if (pindex == pindexFirstNotTreeValid) pindexFirstNotTreeValid = NULL;
+            if (pindex == pindexFirstNotTransactionsValid) pindexFirstNotTransactionsValid = NULL;
             if (pindex == pindexFirstNotChainValid) pindexFirstNotChainValid = NULL;
             if (pindex == pindexFirstNotScriptsValid) pindexFirstNotScriptsValid = NULL;
             // Find our parent.