validation: move nChainTx assert down in CheckBlockIndex

There is a designated section meant for the actual consistency
checks, marked by a comment.

Author: mzumsande

src/validation.cpp

@@ -4862,16 +4862,6 @@ void ChainstateManager::CheckBlockIndex()
     CBlockIndex* pindexFirstAssumeValid = nullptr; // Oldest ancestor of pindex which has BLOCK_ASSUMED_VALID
     while (pindex != nullptr) {
         nNodes++;
-        // Make sure nChainTx sum is correctly computed.
-        unsigned int prev_chain_tx = pindex->pprev ? pindex->pprev->nChainTx : 0;
-        assert((pindex->nChainTx == pindex->nTx + prev_chain_tx)
-               // Transaction may be completely unset - happens if only the header was accepted but the block hasn't been processed.
-               || (pindex->nChainTx == 0 && pindex->nTx == 0)
-               // nChainTx may be unset, but nTx set (if a block has been accepted, but one of its predecessors hasn't been processed yet)
-               || (pindex->nChainTx == 0 && prev_chain_tx == 0 && pindex->pprev)
-               // Transaction counts prior to snapshot are unknown.
-               || pindex->IsAssumedValid());
-
         if (pindexFirstAssumeValid == nullptr && pindex->nStatus & BLOCK_ASSUMED_VALID) pindexFirstAssumeValid = pindex;
         if (pindexFirstInvalid == nullptr && pindex->nStatus & BLOCK_FAILED_VALID) pindexFirstInvalid = pindex;
         if (pindexFirstMissing == nullptr && !(pindex->nStatus & BLOCK_HAVE_DATA)) {
@@ -4954,6 +4944,15 @@ void ChainstateManager::CheckBlockIndex()
             // Checks for not-invalid blocks.
             assert((pindex->nStatus & BLOCK_FAILED_MASK) == 0); // The failed mask cannot be set for blocks without invalid parents.
         }
+        // Make sure nChainTx sum is correctly computed.
+        unsigned int prev_chain_tx = pindex->pprev ? pindex->pprev->nChainTx : 0;
+        assert((pindex->nChainTx == pindex->nTx + prev_chain_tx)
+               // Transaction may be completely unset - happens if only the header was accepted but the block hasn't been processed.
+               || (pindex->nChainTx == 0 && pindex->nTx == 0)
+               // nChainTx may be unset, but nTx set (if a block has been accepted, but one of its predecessors hasn't been processed yet)
+               || (pindex->nChainTx == 0 && prev_chain_tx == 0 && pindex->pprev)
+               // Transaction counts prior to snapshot are unknown.
+               || pindex->IsAssumedValid());
         // Chainstate-specific checks on setBlockIndexCandidates
         for (auto c : GetAll()) {
             if (c->m_chain.Tip() == nullptr) continue;