index: add [nodiscard] attribute to functions writing to the db

Author: furszy

src/index/blockfilterindex.cpp

@@ -260,7 +260,7 @@ bool BlockFilterIndex::CustomAppend(const interfaces::BlockInfo& block)
     return true;
 }
 
-static bool CopyHeightIndexToHashIndex(CDBIterator& db_it, CDBBatch& batch,
+[[nodiscard]] static bool CopyHeightIndexToHashIndex(CDBIterator& db_it, CDBBatch& batch,
                                        const std::string& index_name,
                                        int start_height, int stop_height)
 {

src/index/coinstatsindex.cpp

@@ -235,7 +235,7 @@ bool CoinStatsIndex::CustomAppend(const interfaces::BlockInfo& block)
     return m_db->Write(DBHeightKey(block.height), value);
 }
 
-static bool CopyHeightIndexToHashIndex(CDBIterator& db_it, CDBBatch& batch,
+[[nodiscard]] static bool CopyHeightIndexToHashIndex(CDBIterator& db_it, CDBBatch& batch,
                                        const std::string& index_name,
                                        int start_height, int stop_height)
 {

src/index/coinstatsindex.h

@@ -38,7 +38,7 @@ class CoinStatsIndex final : public BaseIndex
     CAmount m_total_unspendables_scripts{0};
     CAmount m_total_unspendables_unclaimed_rewards{0};
 
-    bool ReverseBlock(const CBlock& block, const CBlockIndex* pindex);
+    [[nodiscard]] bool ReverseBlock(const CBlock& block, const CBlockIndex* pindex);
 
     bool AllowPrune() const override { return true; }
 

src/index/txindex.cpp

@@ -26,7 +26,7 @@ class TxIndex::DB : public BaseIndex::DB
     bool ReadTxPos(const uint256& txid, CDiskTxPos& pos) const;
 
     /// Write a batch of transaction positions to the DB.
-    bool WriteTxs(const std::vector<std::pair<uint256, CDiskTxPos>>& v_pos);
+    [[nodiscard]] bool WriteTxs(const std::vector<std::pair<uint256, CDiskTxPos>>& v_pos);
 };
 
 TxIndex::DB::DB(size_t n_cache_size, bool f_memory, bool f_wipe) :