Merge #14138: wallet: Set encrypted_batch to nullptr after delete. Avoid double free in the case of NDEBUG.

fa462b3 wallet: Set encrypted_batch to nullptr after delete. Avoid double free in the case of NDEBUG. (practicalswift)

Pull request description:

  Set `encrypted_batch` to `nullptr` after delete. Avoid double free in the case of `NDEBUG`.

Tree-SHA512: 6f5ab40c82dd8c8713bbf1aacacdc837277c04769807f985248546be1c7ea269813c95379fbef982ac5683a45af0225613460a7446c39673b033f5f5edde2f5a

Author: laanwj

src/wallet/wallet.cpp

@@ -687,6 +687,7 @@ bool CWallet::EncryptWallet(const SecureString& strWalletPassphrase)
         {
             encrypted_batch->TxnAbort();
             delete encrypted_batch;
+            encrypted_batch = nullptr;
             // We now probably have half of our keys encrypted in memory, and half not...
             // die and let the user reload the unencrypted wallet.
             assert(false);
@@ -697,6 +698,7 @@ bool CWallet::EncryptWallet(const SecureString& strWalletPassphrase)
 
         if (!encrypted_batch->TxnCommit()) {
             delete encrypted_batch;
+            encrypted_batch = nullptr;
             // We now have keys encrypted in memory, but not on disk...
             // die to avoid confusion and let the user reload the unencrypted wallet.
             assert(false);