Implement transaction support in Go adapter

bindings/go/connection.go

@@ -1,6 +1,7 @@
 package limbo
 
 import (
+	"context"
 	"database/sql"
 	"database/sql/driver"
 	"errors"
@@ -136,7 +137,94 @@ func (c *limboConn) Prepare(query string) (driver.Stmt, error) {
 	return newStmt(stmtPtr, query), nil
 }
 
-// begin is needed to implement driver.Conn.. for now not implemented
-func (c *limboConn) Begin() (driver.Tx, error) {
-	return nil, errors.New("transactions not implemented")
+// limboTx implements driver.Tx
+type limboTx struct {
+	conn *limboConn
+}
+
+// Begin starts a new transaction with default isolation level
+func (c *limboConn) Begin() (driver.Tx, error) {
+	c.Lock()
+	defer c.Unlock()
+
+	if c.ctx == 0 {
+		return nil, errors.New("connection closed")
+	}
+
+	// Execute BEGIN statement
+	stmtPtr := connPrepare(c.ctx, "BEGIN")
+	if stmtPtr == 0 {
+		return nil, c.getError()
+	}
+
+	stmt := newStmt(stmtPtr, "BEGIN")
+	defer stmt.Close()
+
+	_, err := stmt.Exec(nil)
+	if err != nil {
+		return nil, err
+	}
+
+	return &limboTx{conn: c}, nil
+}
+
+// BeginTx starts a transaction with the specified options.
+// Currently only supports default isolation level and non-read-only transactions.
+func (c *limboConn) BeginTx(ctx context.Context, opts driver.TxOptions) (driver.Tx, error) {
+	// Skip handling non-default isolation levels and read-only mode
+	// for now, letting database/sql package handle these cases
+	if opts.Isolation != driver.IsolationLevel(sql.LevelDefault) || opts.ReadOnly {
+		return nil, driver.ErrSkip
+	}
+
+	// Check for context cancellation
+	select {
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	default:
+		return c.Begin()
+	}
+}
+
+// Commit commits the transaction
+func (tx *limboTx) Commit() error {
+	tx.conn.Lock()
+	defer tx.conn.Unlock()
+
+	if tx.conn.ctx == 0 {
+		return errors.New("connection closed")
+	}
+
+	stmtPtr := connPrepare(tx.conn.ctx, "COMMIT")
+	if stmtPtr == 0 {
+		return tx.conn.getError()
+	}
+
+	stmt := newStmt(stmtPtr, "COMMIT")
+	defer stmt.Close()
+
+	_, err := stmt.Exec(nil)
+	return err
+}
+
+// Rollback aborts the transaction.
+// Note: This operation is not currently fully supported by Limbo and will return an error.
+func (tx *limboTx) Rollback() error {
+	tx.conn.Lock()
+	defer tx.conn.Unlock()
+
+	if tx.conn.ctx == 0 {
+		return errors.New("connection closed")
+	}
+
+	stmtPtr := connPrepare(tx.conn.ctx, "ROLLBACK")
+	if stmtPtr == 0 {
+		return tx.conn.getError()
+	}
+
+	stmt := newStmt(stmtPtr, "ROLLBACK")
+	defer stmt.Close()
+
+	_, err := stmt.Exec(nil)
+	return err
 }

bindings/go/limbo_test.go

@@ -9,8 +9,10 @@ import (
 	_ "github.com/tursodatabase/limbo"
 )
 
-var conn *sql.DB
-var connErr error
+var (
+	conn    *sql.DB
+	connErr error
+)
 
 func TestMain(m *testing.M) {
 	conn, connErr = sql.Open("sqlite3", ":memory:")
@@ -59,7 +61,7 @@ func TestQuery(t *testing.T) {
 			t.Errorf("Expected column %d to be %s, got %s", i, expectedCols[i], col)
 		}
 	}
-	var i = 1
+	i := 1
 	for rows.Next() {
 		var a int
 		var b string
@@ -78,7 +80,6 @@ func TestQuery(t *testing.T) {
 	if err = rows.Err(); err != nil {
 		t.Fatalf("Row iteration error: %v", err)
 	}
-
 }
 
 func TestFunctions(t *testing.T) {
@@ -280,6 +281,81 @@ func TestDriverRowsErrorMessages(t *testing.T) {
 	t.Log("Rows error behavior test passed")
 }
 
+func TestTransaction(t *testing.T) {
+	// Open database connection
+	db, err := sql.Open("sqlite3", ":memory:")
+	if err != nil {
+		t.Fatalf("Error opening database: %v", err)
+	}
+	defer db.Close()
+
+	// Create a test table
+	_, err = db.Exec("CREATE TABLE test (id INTEGER PRIMARY KEY, name TEXT)")
+	if err != nil {
+		t.Fatalf("Error creating table: %v", err)
+	}
+
+	// Insert initial data
+	_, err = db.Exec("INSERT INTO test (id, name) VALUES (1, 'Initial')")
+	if err != nil {
+		t.Fatalf("Error inserting initial data: %v", err)
+	}
+
+	// Begin a transaction
+	tx, err := db.Begin()
+	if err != nil {
+		t.Fatalf("Error starting transaction: %v", err)
+	}
+
+	// Insert data within the transaction
+	_, err = tx.Exec("INSERT INTO test (id, name) VALUES (2, 'Transaction')")
+	if err != nil {
+		t.Fatalf("Error inserting data in transaction: %v", err)
+	}
+
+	// Commit the transaction
+	err = tx.Commit()
+	if err != nil {
+		t.Fatalf("Error committing transaction: %v", err)
+	}
+
+	// Verify both rows are visible after commit
+	rows, err := db.Query("SELECT id, name FROM test ORDER BY id")
+	if err != nil {
+		t.Fatalf("Error querying data after commit: %v", err)
+	}
+	defer rows.Close()
+
+	expected := []struct {
+		id   int
+		name string
+	}{
+		{1, "Initial"},
+		{2, "Transaction"},
+	}
+
+	i := 0
+	for rows.Next() {
+		var id int
+		var name string
+		if err := rows.Scan(&id, &name); err != nil {
+			t.Fatalf("Error scanning row: %v", err)
+		}
+
+		if id != expected[i].id || name != expected[i].name {
+			t.Errorf("Row %d: expected (%d, %s), got (%d, %s)",
+				i, expected[i].id, expected[i].name, id, name)
+		}
+		i++
+	}
+
+	if i != 2 {
+		t.Fatalf("Expected 2 rows, got %d", i)
+	}
+
+	t.Log("Transaction test passed")
+}
+
 func slicesAreEq(a, b []byte) bool {
 	if len(a) != len(b) {
 		fmt.Printf("LENGTHS NOT EQUAL: %d != %d\n", len(a), len(b))