Merge bitcoin#2675: [Wallet] Clear Shield notes witness cache before …

…a full rescan

fb025b1 [Wallet] Clear Shield notes witness cache before a full rescan (random-zebra)

Pull request description:

  So they are rebuilt via `ScanForWalletTransactions` --> `ChainTipAdded`, and a corrupted cache can be fixed with a simple `-rescan` of the chain data (instead of a complete reindex).

ACKs for top commit:
  furszy:
    ACK fb025b1
  Fuzzbawls:
    ACK fb025b1

Tree-SHA512: 3963d2fa4586bfc999a96f76e4fe537c484ccc07e9b7cebfa32dba771d4113e3f5a583b45bf4ee1010be2bdca4a27aab662054a391f6e30c705af41771e2d144

src/wallet/wallet.cpp

@@ -4280,7 +4280,11 @@ CWallet* CWallet::CreateWalletFromFile(const std::string& name, const fs::path&
 
     LOCK(cs_main);
     CBlockIndex* pindexRescan = chainActive.Genesis();
-    if (!gArgs.GetBoolArg("-rescan", false)) {
+
+    if (gArgs.GetBoolArg("-rescan", false)) {
+        // clear note witness cache before a full rescan
+        walletInstance->ClearNoteWitnessCache();
+    } else {
         WalletBatch batch(*walletInstance->database);
         CBlockLocator locator;
         if (batch.ReadBestBlock(locator))
@@ -4621,6 +4625,8 @@ void CWallet::IncrementNoteWitnesses(const CBlockIndex* pindex,
 
 void CWallet::DecrementNoteWitnesses(const CBlockIndex* pindex) { m_sspk_man->DecrementNoteWitnesses(pindex->nHeight); }
 
+void CWallet::ClearNoteWitnessCache() { m_sspk_man->ClearNoteWitnessCache(); }
+
 bool CWallet::AddSaplingZKey(const libzcash::SaplingExtendedSpendingKey &key) { return m_sspk_man->AddSaplingZKey(key); }
 
 bool CWallet::AddSaplingIncomingViewingKeyW(

src/wallet/wallet.h

@@ -930,6 +930,9 @@ class CWallet : public CCryptoKeyStore, public CValidationInterface
     //! pindex is the old tip being disconnected.
     void DecrementNoteWitnesses(const CBlockIndex* pindex);
 
+    //! clear note witness cache
+    void ClearNoteWitnessCache();
+
 
     //! Adds Sapling spending key to the store, and saves it to disk
     bool AddSaplingZKey(const libzcash::SaplingExtendedSpendingKey &key);