From 12daf6fcdcbf5c7f03038338d843df3877714b24 Mon Sep 17 00:00:00 2001
From: furszy <matiasfurszyfer@protonmail.com>
Date: Mon, 5 Dec 2022 18:04:56 -0300
Subject: [PATCH] walletdb: scope bdb::EraseRecords under a single db txn

so we erase all the records atomically or abort the entire
procedure.

and, at the same time, we can share the same db txn context
for the db cursor and the erase functionality.

extra note from the Db.cursor doc:
"If transaction protection is enabled, cursors must be
opened and closed within the context of a transaction"

thus why added a `CloseCursor` call before calling to
`TxnAbort/TxnCommit`.
---
 src/wallet/walletdb.cpp | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/src/wallet/walletdb.cpp b/src/wallet/walletdb.cpp
index 072357022e..9a6c5afba6 100644
--- a/src/wallet/walletdb.cpp
+++ b/src/wallet/walletdb.cpp
@@ -1136,6 +1136,9 @@ bool WalletBatch::WriteWalletFlags(const uint64_t flags)
 
 bool WalletBatch::EraseRecords(const std::unordered_set<std::string>& types)
 {
+    // Begin db txn
+    if (!m_batch->TxnBegin()) return false;
+
     // Get cursor
     std::unique_ptr<DatabaseCursor> cursor = m_batch->GetNewCursor();
     if (!cursor)
@@ -1144,8 +1147,7 @@ bool WalletBatch::EraseRecords(const std::unordered_set<std::string>& types)
     }
 
     // Iterate the DB and look for any records that have the type prefixes
-    while (true)
-    {
+    while (true) {
         // Read next record
         DataStream key{};
         DataStream value{};
@@ -1153,6 +1155,8 @@ bool WalletBatch::EraseRecords(const std::unordered_set<std::string>& types)
         if (status == DatabaseCursor::Status::DONE) {
             break;
         } else if (status == DatabaseCursor::Status::FAIL) {
+            cursor.reset(nullptr);
+            m_batch->TxnAbort(); // abort db txn
             return false;
         }
 
@@ -1163,10 +1167,16 @@ bool WalletBatch::EraseRecords(const std::unordered_set<std::string>& types)
         key >> type;
 
         if (types.count(type) > 0) {
-            m_batch->Erase(key_data);
+            if (!m_batch->Erase(key_data)) {
+                cursor.reset(nullptr);
+                m_batch->TxnAbort();
+                return false; // erase failed
+            }
         }
     }
-    return true;
+    // Finish db txn
+    cursor.reset(nullptr);
+    return m_batch->TxnCommit();
 }
 
 bool WalletBatch::TxnBegin()