Merge bitcoin#21127: wallet: load flags before everything else

9305862 wallet: load flags before everything else (Sjors Provoost)

Pull request description:

  Load and set wallet flags before processing other records. That way we can take them into account while processing those other records.

  Suggested here:
  bitcoin#16546 (comment)

ACKs for top commit:
  laanwj:
    Code review ACK 9305862
  gruve-p:
    ACK bitcoin@9305862
  achow101:
    ACK 9305862

Tree-SHA512: 7104523e369ce3c670571fe5e8b52c67b9ca92b8e36a2da5eb6f9f8bf8ed0544897007257204b68f6f371d682b3ef0d0635d36e6e8416ac74af1999d9fbc869c

src/wallet/walletdb.cpp

@@ -665,7 +665,8 @@ ReadKeyValue(CWallet* pwallet, CDataStream& ssKey, CDataStream& ssValue,
         } else if (strType != DBKeys::BESTBLOCK && strType != DBKeys::BESTBLOCK_NOMERKLE &&
                    strType != DBKeys::MINVERSION && strType != DBKeys::ACENTRY &&
                    strType != DBKeys::VERSION && strType != DBKeys::SETTINGS &&
-                   strType != DBKeys::PRIVATESEND_SALT && strType != DBKeys::COINJOIN_SALT) {
+                   strType != DBKeys::PRIVATESEND_SALT && strType != DBKeys::COINJOIN_SALT &&
+                   strType != DBKeys::FLAGS) {
             wss.m_unknown_records++;
         }
     } catch (const std::exception& e) {
@@ -711,6 +712,16 @@ DBErrors WalletBatch::LoadWallet(CWallet* pwallet)
             pwallet->LoadMinVersion(nMinVersion);
         }
 
+        // Load wallet flags, so they are known when processing other records.
+        // The FLAGS key is absent during wallet creation.
+        uint64_t flags;
+        if (m_batch->Read(DBKeys::FLAGS, flags)) {
+            if (!pwallet->LoadWalletFlags(flags)) {
+                pwallet->WalletLogPrintf("Error reading wallet database: Unknown non-tolerable wallet flags found\n");
+                return DBErrors::CORRUPT;
+            }
+        }
+
         // Get cursor
         if (!m_batch->StartCursor())
         {