Merge #16502: wallet: Drop unused OldKey

0b1f4b3c6685d0a6307926d43d166add538061b7 wallet: Drop unused OldKey (João Barbosa)

Pull request description:

  Replaces #16494, `OldKey` (previously `CWalletKey`) was never serialized in the code history which means that unserialization support is not required, so remove the code entirely.

ACKs for top commit:
  jnewbery:
    ACK 0b1f4b3c6685d0a6307926d43d166add538061b7
  laanwj:
    ACK 0b1f4b3c6685d0a6307926d43d166add538061b7
  fanquake:
    ACK 0b1f4b3c6685d0a6307926d43d166add538061b7

Tree-SHA512: 92e9b2d6fc41f2765492d5d69d18fc4302c40ab44f28c8c30ca652c72767fbc484848c51a38ecf1f447849767a583c398784408bb5f64f9c86f9a5872b325ffc

2 files changed, 7 insertions, 33 deletions

diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index 86c2cf851c..8b0ae8bb85 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -663,28 +663,6 @@ public:
     }
 };
 
-/** Private key that was serialized by an old wallet (only used for deserialization) */
-struct OldKey {
-    CPrivKey vchPrivKey;
-    ADD_SERIALIZE_METHODS;
-
-    template <typename Stream, typename Operation>
-    inline void SerializationOp(Stream& s, Operation ser_action) {
-        // no longer used by the wallet, thus dropped after deserialization:
-        int64_t nTimeCreated;
-        int64_t nTimeExpires;
-        std::string strComment;
-
-        int nVersion = s.GetVersion();
-        if (!(s.GetType() & SER_GETHASH))
-            READWRITE(nVersion);
-        READWRITE(vchPrivKey);
-        READWRITE(nTimeCreated);
-        READWRITE(nTimeExpires);
-        READWRITE(LIMITED_STRING(strComment, 65536));
-    }
-};
-
 struct CoinSelectionParams
 {
     bool use_bnb = true;
diff --git a/src/wallet/walletdb.cpp b/src/wallet/walletdb.cpp
index 9f467c0f5a..635997afc9 100644
--- a/src/wallet/walletdb.cpp
+++ b/src/wallet/walletdb.cpp
@@ -115,7 +115,6 @@ bool WalletBatch::WriteCryptedKey(const CPubKey& vchPubKey,
         return false;
     }
     EraseIC(std::make_pair(DBKeys::KEY, vchPubKey));
-    EraseIC(std::make_pair(DBKeys::OLD_KEY, vchPubKey));
     return true;
 }
 
@@ -256,7 +255,7 @@ ReadKeyValue(CWallet* pwallet, CDataStream& ssKey, CDataStream& ssValue,
             ssValue >> fYes;
             if (fYes == '1')
                 pwallet->LoadWatchOnly(script);
-        } else if (strType == DBKeys::KEY || strType == DBKeys::OLD_KEY) {
+        } else if (strType == DBKeys::KEY) {
             CPubKey vchPubKey;
             ssKey >> vchPubKey;
             if (!vchPubKey.IsValid())
@@ -268,14 +267,8 @@ ReadKeyValue(CWallet* pwallet, CDataStream& ssKey, CDataStream& ssValue,
             CPrivKey pkey;
             uint256 hash;
 
-            if (strType == DBKeys::KEY) {
-                wss.nKeys++;
-                ssValue >> pkey;
-            } else {
-                OldKey wkey;
-                ssValue >> wkey;
-                pkey = wkey.vchPrivKey;
-            }
+            wss.nKeys++;
+            ssValue >> pkey;
 
             // Old wallets store keys as DBKeys::KEY [pubkey] => [privkey]
             // ... which was slow for wallets with lots of keys, because the public key is re-derived from the private key
@@ -407,6 +400,9 @@ ReadKeyValue(CWallet* pwallet, CDataStream& ssKey, CDataStream& ssValue,
                 strErr = "Error reading wallet database: Unknown non-tolerable wallet flags found";
                 return false;
             }
+        } else if (strType == DBKeys::OLD_KEY) {
+            strErr = "Found unsupported 'wkey' record, try loading with version 0.18";
+            return false;
         } else if (strType != DBKeys::BESTBLOCK && strType != DBKeys::BESTBLOCK_NOMERKLE &&
                    strType != DBKeys::MINVERSION && strType != DBKeys::ACENTRY &&
                    strType != DBKeys::VERSION && strType != DBKeys::SETTINGS) {
@@ -428,7 +424,7 @@ ReadKeyValue(CWallet* pwallet, CDataStream& ssKey, CDataStream& ssValue,
 
 bool WalletBatch::IsKeyType(const std::string& strType)
 {
-    return (strType == DBKeys::KEY || strType == DBKeys::OLD_KEY ||
+    return (strType == DBKeys::KEY ||
             strType == DBKeys::MASTER_KEY || strType == DBKeys::CRYPTED_KEY);
 }