rpc: check block index before reading block / undo data

This avoids low-level log errors that are supposed to only occur when
there is an actual problem with the block on disk missing unexpectedly,
but not in the case where the block and/or undo data are expected not to be there.

src/rpc/blockchain.cpp

@@ -184,7 +184,7 @@ UniValue blockToJSON(BlockManager& blockman, const CBlock& block, const CBlockIn
         case TxVerbosity::SHOW_DETAILS_AND_PREVOUT:
             CBlockUndo blockUndo;
             const bool is_not_pruned{WITH_LOCK(::cs_main, return !blockman.IsBlockPruned(blockindex))};
-            const bool have_undo{is_not_pruned && blockman.UndoReadFromDisk(blockUndo, blockindex)};
+            const bool have_undo{is_not_pruned && WITH_LOCK(::cs_main, return blockindex.nStatus & BLOCK_HAVE_UNDO) && blockman.UndoReadFromDisk(blockUndo, blockindex)};
 
             for (size_t i = 0; i < block.vtx.size(); ++i) {
                 const CTransactionRef& tx = block.vtx.at(i);

src/rpc/rawtransaction.cpp

@@ -405,7 +405,7 @@ static RPCHelpMan getrawtransaction()
     CBlockUndo blockUndo;
     CBlock block;
 
-    if (tx->IsCoinBase() || !blockindex || WITH_LOCK(::cs_main, return chainman.m_blockman.IsBlockPruned(*blockindex)) ||
+    if (tx->IsCoinBase() || !blockindex || WITH_LOCK(::cs_main, return !(blockindex->nStatus & BLOCK_HAVE_UNDO) || !(blockindex->nStatus & BLOCK_HAVE_DATA)) ||
         !(chainman.m_blockman.UndoReadFromDisk(blockUndo, *blockindex) && chainman.m_blockman.ReadBlockFromDisk(block, *blockindex))) {
         TxToJSON(*tx, hash_block, result, chainman.ActiveChainstate());
         return result;