From 440d7f393d74f309d29e1d10ba1f11c41c869226 Mon Sep 17 00:00:00 2001
From: bitflash <dev@bitflash.network>
Date: Tue, 18 Aug 2026 14:33:40 -0300
Subject: wallet: bracket WriteHDMaster in a SQLite runtime transaction

The SQLite runtime wrote each record as its own autocommit, so a group
that must land together -- hdmaster and hdchaincode, the two halves of an
HD seed -- could be left half-written by a failure or crash between them,
the incomplete-seed state -walletstoragecheck exists to catch. Berkeley DB
was no worse (it is not transactional here either) but no better.

Add WalletSQLiteRuntimeBeginTxn/CommitTxn/RollbackTxn -- no-ops that
succeed when the SQLite backend is not active, so Berkeley DB keeps its
existing per-write behaviour -- and wrap WriteHDMaster in them so the seed
lands all-or-nothing under SQLite. The one BDB-atomic wallet rewrite, the
encrypt path, is already matched by its own transaction in the SQLite
encrypt branch; every other wallet multi-write is ordering-based on both
backends by design.

wallet-sqlite self-test now proves the bracket: a rolled-back runtime
write leaves no record, a committed one persists, and WriteHDMaster lands
both halves of the seed.
---
 src/db.cpp | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

(limited to 'src/db.cpp')

diff --git a/src/db.cpp b/src/db.cpp
index 86f6dd7..c16edb4 100644
--- a/src/db.cpp
+++ b/src/db.cpp
@@ -164,6 +164,40 @@ bool WalletSQLiteRuntimeEraseRecord(const vector<unsigned char>& vchKey)
     return pWalletSQLiteRuntime->EraseRecord(vchKey, strError);
 }
 
+// Transaction bracket for the SQLite runtime. When the SQLite backend is not
+// active these are no-ops that succeed, so a caller can wrap a group of related
+// writes and Berkeley DB keeps its existing per-write behaviour unchanged while
+// SQLite gets all-or-nothing.
+bool WalletSQLiteRuntimeBeginTxn()
+{
+    if (!pWalletSQLiteRuntime)
+        return true;
+    string strError;
+    if (pWalletSQLiteRuntime->BeginTransaction(strError))
+        return true;
+    printf("WalletSQLiteRuntimeBeginTxn() : %s\n", strError.c_str());
+    return false;
+}
+
+bool WalletSQLiteRuntimeCommitTxn()
+{
+    if (!pWalletSQLiteRuntime)
+        return true;
+    string strError;
+    if (pWalletSQLiteRuntime->CommitTransaction(strError))
+        return true;
+    printf("WalletSQLiteRuntimeCommitTxn() : %s\n", strError.c_str());
+    return false;
+}
+
+void WalletSQLiteRuntimeRollbackTxn()
+{
+    if (!pWalletSQLiteRuntime)
+        return;
+    string strError;
+    pWalletSQLiteRuntime->RollbackTransaction(strError);
+}
+
 
 CDB::CDB(const char* pszFile, const char* pszMode, bool fTxn) : pdb(NULL)
 {
-- 
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