Fix MVCC startup infinite loop when using existing DB

MVCC bootstrap connection got stuck into an infinite statement
reparsing loop because the bootstrap procedure happened before the
on-disk schema was deserialized.

core/lib.rs

@@ -451,15 +451,6 @@ impl Database {
             n_connections: AtomicUsize::new(0),
         });
 
-        if opts.enable_mvcc {
-            let mv_store = db.mv_store.as_ref().unwrap();
-            let mvcc_bootstrap_conn = db.connect_mvcc_bootstrap()?;
-            mv_store.bootstrap(mvcc_bootstrap_conn)?;
-        }
-
-        db.register_global_builtin_extensions()
-            .expect("unable to register global extensions");
-
         // Check: https://github.com/tursodatabase/turso/pull/1761#discussion_r2154013123
         if db_state.is_initialized() {
             // parse schema
@@ -502,6 +493,15 @@ impl Database {
             })?;
         }
 
+        if opts.enable_mvcc {
+            let mv_store = db.mv_store.as_ref().unwrap();
+            let mvcc_bootstrap_conn = db.connect_mvcc_bootstrap()?;
+            mv_store.bootstrap(mvcc_bootstrap_conn)?;
+        }
+
+        db.register_global_builtin_extensions()
+            .expect("unable to register global extensions");
+
         Ok(db)
     }
 

tests/integration/query_processing/test_transactions.rs

@@ -646,6 +646,43 @@ fn test_mvcc_recovery_of_both_checkpointed_and_noncheckpointed_tables_works() {
     assert_eq!(rows, expected2);
 }
 
+#[test]
+fn test_non_mvcc_to_mvcc() {
+    // Create non-mvcc database
+    let tmp_db = TempDatabase::new("test_non_mvcc_to_mvcc.db", false);
+    let conn = tmp_db.connect_limbo();
+
+    // Create table and insert data
+    execute_and_log(
+        &conn,
+        "CREATE TABLE test (id INTEGER PRIMARY KEY, value TEXT)",
+    )
+    .unwrap();
+    execute_and_log(&conn, "INSERT INTO test VALUES (1, 'hello')").unwrap();
+
+    // Checkpoint to persist changes
+    execute_and_log(&conn, "PRAGMA wal_checkpoint(TRUNCATE)").unwrap();
+
+    let path = tmp_db.path.clone();
+    drop(conn);
+    drop(tmp_db);
+
+    // Reopen in mvcc mode
+    let tmp_db = TempDatabase::new_with_existent_with_opts(
+        &path,
+        turso_core::DatabaseOpts::new().with_mvcc(true),
+    );
+    let conn = tmp_db.connect_limbo();
+
+    // Query should work
+    let stmt = query_and_log(&conn, "SELECT * FROM test").unwrap().unwrap();
+    let rows = helper_read_all_rows(stmt);
+
+    assert_eq!(rows.len(), 1);
+    assert_eq!(rows[0][0], Value::Integer(1));
+    assert_eq!(rows[0][1], Value::Text("hello".into()));
+}
+
 fn helper_read_all_rows(mut stmt: turso_core::Statement) -> Vec<Vec<Value>> {
     let mut ret = Vec::new();
     loop {