wallet: store m_additional_flags in SQLiteDatabase to fix reopen path

SQLiteDatabase::Open() (the public override) always reopens the database
with no additional flags. If SQLiteBatch::Close() triggers the
force_conn_refresh path (TxnAbort failed), it calls Open() which drops
the original additional_flags, causing in-memory databases to be reopened
as on-disk instead.

Store additional_flags as a member and use it in Open() so the reconnect
preserves the original flags. For in-memory databases, connection recovery
makes no sense as all data would be lost; both the force_conn_refresh path
and the public Open() now throw instead.

Co-authored-by: Sjors Provoost <sjors@sprovoost.nl>

src/wallet/sqlite.cpp

@@ -116,7 +116,7 @@ SQLiteDatabase::SQLiteDatabase(const fs::path& dir_path, const fs::path& file_pa
 {}
 
 SQLiteDatabase::SQLiteDatabase(const fs::path& dir_path, const fs::path& file_path, const DatabaseOptions& options, int additional_flags)
-    : WalletDatabase(), m_dir_path(dir_path), m_file_path(fs::PathToString(file_path)), m_write_semaphore(1), m_use_unsafe_sync(options.use_unsafe_sync)
+    : WalletDatabase(), m_dir_path(dir_path), m_file_path(fs::PathToString(file_path)), m_additional_flags(additional_flags), m_write_semaphore(1), m_use_unsafe_sync(options.use_unsafe_sync)
 {
     {
         LOCK(g_sqlite_mutex);
@@ -139,7 +139,7 @@ SQLiteDatabase::SQLiteDatabase(const fs::path& dir_path, const fs::path& file_pa
     }
 
     try {
-        Open(additional_flags);
+        Open(m_additional_flags);
     } catch (const std::runtime_error&) {
         // If open fails, cleanup this object and rethrow the exception
         Cleanup();
@@ -247,7 +247,10 @@ bool SQLiteDatabase::Verify(bilingual_str& error)
 
 void SQLiteDatabase::Open()
 {
-    Open(/*additional_flags*/0);
+    if (m_additional_flags & SQLITE_OPEN_MEMORY) {
+        throw std::runtime_error("SQLiteDatabase: Cannot reopen an in-memory database");
+    }
+    Open(m_additional_flags);
 }
 
 void SQLiteDatabase::Open(int additional_flags)
@@ -448,6 +451,9 @@ void SQLiteBatch::Close()
     }
 
     if (force_conn_refresh) {
+        if (m_database.m_additional_flags & SQLITE_OPEN_MEMORY) {
+            throw std::runtime_error("SQLiteDatabase: Cannot recover in-memory database connection");
+        }
         m_database.Close();
         try {
             m_database.Open();

src/wallet/sqlite.h

@@ -103,10 +103,14 @@ public:
 class SQLiteDatabase : public WalletDatabase
 {
 private:
+    friend class SQLiteBatch;
+
     const fs::path m_dir_path;
 
     const std::string m_file_path;
 
+    const int m_additional_flags;
+
     /**
      * This mutex protects SQLite initialization and shutdown.
      * sqlite3_config() and sqlite3_shutdown() are not thread-safe (sqlite3_initialize() is).