Merge upstream v1.2.20 into the fork

Merges upstream tag v1.2.20 (6aa3dade) into our 1.2.19+sec tree. The merge
base is bc3de30's descendant 9e39a50 -- upstream's own v1.2.19 -- so this is
an ordinary three-way merge, not a replay. Five conflict blocks in four
files, all resolved below.

No consensus change. CheckBlock, ConnectBlock, DisconnectBlock, ConnectInputs,
AcceptBlock, AcceptTransaction, GetNextWorkRequired and GetBlockValue hash
identical to v1.2.19; script.cpp and script.h are byte-identical on both
sides. main.cpp is +3 lines and main.h +2, all wallet-backend plumbing.
rpc.cpp is untouched, so the payout ledger arrives unchanged.

Makefile, VERSION. OURS, renumbered. 1.2.20+sec, for the same reason 1.2.19
carried +sec: this tree is not the upstream release of that number and the
string names every release artifact.

Makefile, AppImage recipe. OURS for the AppDir path, THEIRS for the bundled
library. Upstream's hunk reverts the icon paths to a hardcoded
/tmp/bitflash.AppDir, which is the local-user pre-placement hazard the fork
moved out of /tmp in the first place; taking their side wholesale would have
reintroduced it silently, inside a conflict about something else. The AppDir
stays $(APPDIR), and libsqlite3.so.0 joins the bundled list, which the new
backend genuinely needs.

src/Makefile, src/makefile.mingw, HEADERS. BOTH. Ours drops market.h,
theirs adds wallet_sqlite.h; the resolution does both. NODE_OBJS auto-merged
correctly in both files -- obj/wallet_sqlite.o present, obj/market.o still
gone -- and was verified rather than assumed, because that line has trapped
this fork before.

src/selftest.cpp, known-tests list. BOTH, union. Upstream adds eight
wallet-storage tests, we keep payout-ledger. The dispatch chain itself
auto-merged and still routes payout-ledger to RunPayoutLedgerSelfTest.

Hardening verified intact after merge: the TLS 1.2 floor in nostr.cpp, the
/rvrelay pin, opt-in managed Tor, strict sig3-on-onion descriptor
verification, and the marketplace removal. Upstream shipped no build logs or
__pycache__ this time; the three added files are docs/storage.md and
src/wallet_sqlite.{cpp,h}.

The SQLite backend this release introduces is NOT enabled here. An existing
wallet.dat resolves to Berkeley DB on every branch of the new selection
logic, and the conversion wizard is GUI-only and not compiled into the
headless node. The review findings that gate ever turning it on -- the
non-atomic backend marker, the connection-wide WriteHDMaster transaction,
and the encrypt-swap crash window -- are recorded on the tracker, not fixed
here.

1 files changed, 374 insertions, 0 deletions

diff --git a/src/wallet_sqlite.cpp b/src/wallet_sqlite.cpp
new file mode 100644
index 0000000..f4b4b37
--- /dev/null
+++ b/src/wallet_sqlite.cpp
@@ -0,0 +1,374 @@
+// Copyright (c) 2026 Bitflash developers
+// Distributed under the MIT/X11 software license.
+
+#include "headers.h"
+#include "wallet_sqlite.h"
+
+static void SetSQLiteError(sqlite3* pdb, const string& strContext,
+                           string& strError)
+{
+    if (pdb)
+        strError = strContext + ": " + sqlite3_errmsg(pdb);
+    else
+        strError = strContext;
+}
+
+CWalletDBSQLite::CWalletDBSQLite() : pdb(NULL)
+{
+}
+
+CWalletDBSQLite::~CWalletDBSQLite()
+{
+    Close();
+}
+
+bool CWalletDBSQLite::Open(const string& strPath, string& strError)
+{
+    Close();
+
+    int ret = sqlite3_open_v2(strPath.c_str(), &pdb,
+                              SQLITE_OPEN_READWRITE |
+                              SQLITE_OPEN_CREATE |
+                              SQLITE_OPEN_FULLMUTEX,
+                              NULL);
+    if (ret != SQLITE_OK)
+    {
+        SetSQLiteError(pdb, "cannot open SQLite wallet", strError);
+        Close();
+        return false;
+    }
+
+    sqlite3_busy_timeout(pdb, 5000);
+
+    if (!Exec("PRAGMA journal_mode=WAL;", strError))
+    {
+        Close();
+        return false;
+    }
+    if (!Exec("PRAGMA synchronous=FULL;", strError))
+    {
+        Close();
+        return false;
+    }
+    if (!InitSchema(strError))
+    {
+        Close();
+        return false;
+    }
+    return true;
+}
+
+bool CWalletDBSQLite::OpenReadOnly(const string& strPath, string& strError)
+{
+    Close();
+
+    int ret = sqlite3_open_v2(strPath.c_str(), &pdb,
+                              SQLITE_OPEN_READONLY |
+                              SQLITE_OPEN_FULLMUTEX,
+                              NULL);
+    if (ret != SQLITE_OK)
+    {
+        SetSQLiteError(pdb, "cannot open SQLite wallet read-only", strError);
+        Close();
+        return false;
+    }
+
+    sqlite3_busy_timeout(pdb, 5000);
+    return true;
+}
+
+void CWalletDBSQLite::Close()
+{
+    if (pdb)
+    {
+        sqlite3_close(pdb);
+        pdb = NULL;
+    }
+}
+
+bool CWalletDBSQLite::BeginTransaction(string& strError)
+{
+    if (!pdb)
+    {
+        strError = "SQLite wallet is not open";
+        return false;
+    }
+    return Exec("BEGIN IMMEDIATE;", strError);
+}
+
+bool CWalletDBSQLite::CommitTransaction(string& strError)
+{
+    if (!pdb)
+    {
+        strError = "SQLite wallet is not open";
+        return false;
+    }
+    return Exec("COMMIT;", strError);
+}
+
+bool CWalletDBSQLite::RollbackTransaction(string& strError)
+{
+    if (!pdb)
+    {
+        strError = "SQLite wallet is not open";
+        return false;
+    }
+    return Exec("ROLLBACK;", strError);
+}
+
+bool CWalletDBSQLite::Checkpoint(string& strError)
+{
+    if (!pdb)
+    {
+        strError = "SQLite wallet is not open";
+        return false;
+    }
+    return Exec("PRAGMA wal_checkpoint(TRUNCATE);", strError);
+}
+
+bool CWalletDBSQLite::Exec(const char* pszSql, string& strError)
+{
+    char* pszErr = NULL;
+    int ret = sqlite3_exec(pdb, pszSql, NULL, NULL, &pszErr);
+    if (ret != SQLITE_OK)
+    {
+        if (pszErr)
+        {
+            strError = pszErr;
+            sqlite3_free(pszErr);
+        }
+        else
+            SetSQLiteError(pdb, "SQLite exec failed", strError);
+        return false;
+    }
+    return true;
+}
+
+bool CWalletDBSQLite::InitSchema(string& strError)
+{
+    return Exec("CREATE TABLE IF NOT EXISTS wallet_records ("
+                "key BLOB PRIMARY KEY NOT NULL,"
+                "value BLOB NOT NULL"
+                ");",
+                strError) &&
+           Exec("PRAGMA user_version=1;", strError);
+}
+
+bool CWalletDBSQLite::WriteRecord(const vector<unsigned char>& vchKey,
+                                  const vector<unsigned char>& vchValue,
+                                  string& strError,
+                                  bool fOverwrite)
+{
+    if (!pdb)
+    {
+        strError = "SQLite wallet is not open";
+        return false;
+    }
+    if (vchKey.empty())
+    {
+        strError = "SQLite wallet record key is empty";
+        return false;
+    }
+
+    sqlite3_stmt* stmt = NULL;
+    const char* pszSql = fOverwrite
+        ? "INSERT OR REPLACE INTO wallet_records(key, value) VALUES(?, ?);"
+        : "INSERT INTO wallet_records(key, value) VALUES(?, ?);";
+    int ret = sqlite3_prepare_v2(pdb, pszSql, -1, &stmt, NULL);
+    if (ret != SQLITE_OK)
+    {
+        SetSQLiteError(pdb, "cannot prepare SQLite wallet write", strError);
+        return false;
+    }
+
+    ret = sqlite3_bind_blob(stmt, 1, &vchKey[0], (int)vchKey.size(),
+                            SQLITE_TRANSIENT);
+    if (ret == SQLITE_OK)
+        ret = sqlite3_bind_blob(stmt, 2,
+                                vchValue.empty() ? NULL : &vchValue[0],
+                                (int)vchValue.size(),
+                                SQLITE_TRANSIENT);
+    if (ret == SQLITE_OK)
+        ret = sqlite3_step(stmt);
+
+    bool fOk = (ret == SQLITE_DONE);
+    if (!fOk)
+        SetSQLiteError(pdb, "cannot write SQLite wallet record", strError);
+    sqlite3_finalize(stmt);
+    return fOk;
+}
+
+bool CWalletDBSQLite::ReadRecord(const vector<unsigned char>& vchKey,
+                                 vector<unsigned char>& vchValueRet,
+                                 string& strError)
+{
+    vchValueRet.clear();
+    if (!pdb)
+    {
+        strError = "SQLite wallet is not open";
+        return false;
+    }
+    if (vchKey.empty())
+    {
+        strError = "SQLite wallet record key is empty";
+        return false;
+    }
+
+    sqlite3_stmt* stmt = NULL;
+    const char* pszSql = "SELECT value FROM wallet_records WHERE key = ?;";
+    int ret = sqlite3_prepare_v2(pdb, pszSql, -1, &stmt, NULL);
+    if (ret != SQLITE_OK)
+    {
+        SetSQLiteError(pdb, "cannot prepare SQLite wallet read", strError);
+        return false;
+    }
+
+    ret = sqlite3_bind_blob(stmt, 1, &vchKey[0], (int)vchKey.size(),
+                            SQLITE_TRANSIENT);
+    if (ret != SQLITE_OK)
+    {
+        SetSQLiteError(pdb, "cannot bind SQLite wallet key", strError);
+        sqlite3_finalize(stmt);
+        return false;
+    }
+
+    ret = sqlite3_step(stmt);
+    if (ret == SQLITE_ROW)
+    {
+        const unsigned char* pch =
+            (const unsigned char*)sqlite3_column_blob(stmt, 0);
+        int nBytes = sqlite3_column_bytes(stmt, 0);
+        if (nBytes > 0 && pch)
+            vchValueRet.assign(pch, pch + nBytes);
+        sqlite3_finalize(stmt);
+        return true;
+    }
+
+    if (ret == SQLITE_DONE)
+        strError = "SQLite wallet record not found";
+    else
+        SetSQLiteError(pdb, "cannot read SQLite wallet record", strError);
+    sqlite3_finalize(stmt);
+    return false;
+}
+
+bool CWalletDBSQLite::EraseRecord(const vector<unsigned char>& vchKey,
+                                  string& strError)
+{
+    if (!pdb)
+    {
+        strError = "SQLite wallet is not open";
+        return false;
+    }
+    if (vchKey.empty())
+    {
+        strError = "SQLite wallet record key is empty";
+        return false;
+    }
+
+    sqlite3_stmt* stmt = NULL;
+    const char* pszSql = "DELETE FROM wallet_records WHERE key = ?;";
+    int ret = sqlite3_prepare_v2(pdb, pszSql, -1, &stmt, NULL);
+    if (ret != SQLITE_OK)
+    {
+        SetSQLiteError(pdb, "cannot prepare SQLite wallet erase", strError);
+        return false;
+    }
+
+    ret = sqlite3_bind_blob(stmt, 1, &vchKey[0], (int)vchKey.size(),
+                            SQLITE_TRANSIENT);
+    if (ret == SQLITE_OK)
+        ret = sqlite3_step(stmt);
+
+    bool fOk = (ret == SQLITE_DONE);
+    if (!fOk)
+        SetSQLiteError(pdb, "cannot erase SQLite wallet record", strError);
+    sqlite3_finalize(stmt);
+    return fOk;
+}
+
+bool CWalletDBSQLite::ScanRecords(CWalletRecordVisitor& visitor,
+                                  string& strError)
+{
+    if (!pdb)
+    {
+        strError = "SQLite wallet is not open";
+        return false;
+    }
+
+    sqlite3_stmt* stmt = NULL;
+    const char* pszSql = "SELECT key, value FROM wallet_records ORDER BY rowid;";
+    int ret = sqlite3_prepare_v2(pdb, pszSql, -1, &stmt, NULL);
+    if (ret != SQLITE_OK)
+    {
+        SetSQLiteError(pdb, "cannot prepare SQLite wallet scan", strError);
+        return false;
+    }
+
+    while ((ret = sqlite3_step(stmt)) == SQLITE_ROW)
+    {
+        const unsigned char* pchKey =
+            (const unsigned char*)sqlite3_column_blob(stmt, 0);
+        int nKeyBytes = sqlite3_column_bytes(stmt, 0);
+        const unsigned char* pchValue =
+            (const unsigned char*)sqlite3_column_blob(stmt, 1);
+        int nValueBytes = sqlite3_column_bytes(stmt, 1);
+
+        vector<unsigned char> vchKey;
+        vector<unsigned char> vchValue;
+        if (nKeyBytes > 0 && pchKey)
+            vchKey.assign(pchKey, pchKey + nKeyBytes);
+        if (nValueBytes > 0 && pchValue)
+            vchValue.assign(pchValue, pchValue + nValueBytes);
+
+        CDataStream ssKey(vchKey, SER_DISK);
+        CDataStream ssValue(vchValue, SER_DISK);
+        if (!visitor.VisitWalletRecord(ssKey, ssValue, strError))
+        {
+            sqlite3_finalize(stmt);
+            return false;
+        }
+    }
+
+    if (ret != SQLITE_DONE)
+    {
+        SetSQLiteError(pdb, "cannot scan SQLite wallet records", strError);
+        sqlite3_finalize(stmt);
+        return false;
+    }
+
+    sqlite3_finalize(stmt);
+    return true;
+}
+
+bool CWalletDBSQLite::CountRecords(int& nRecordsRet, string& strError)
+{
+    nRecordsRet = 0;
+    if (!pdb)
+    {
+        strError = "SQLite wallet is not open";
+        return false;
+    }
+
+    sqlite3_stmt* stmt = NULL;
+    int ret = sqlite3_prepare_v2(pdb,
+                                 "SELECT COUNT(*) FROM wallet_records;",
+                                 -1, &stmt, NULL);
+    if (ret != SQLITE_OK)
+    {
+        SetSQLiteError(pdb, "cannot prepare SQLite wallet count", strError);
+        return false;
+    }
+
+    ret = sqlite3_step(stmt);
+    if (ret != SQLITE_ROW)
+    {
+        SetSQLiteError(pdb, "cannot count SQLite wallet records", strError);
+        sqlite3_finalize(stmt);
+        return false;
+    }
+
+    nRecordsRet = sqlite3_column_int(stmt, 0);
+    sqlite3_finalize(stmt);
+    return true;
+}