Redundant defers.

Author: ncruces

driver/driver.go

@@ -241,8 +241,9 @@ func (n *connector) Connect(ctx context.Context) (ret driver.Conn, err error) {
 		}
 	}()
 
-	old := c.Conn.SetInterrupt(ctx)
-	defer c.Conn.SetInterrupt(old)
+	if old := c.Conn.SetInterrupt(ctx); old != ctx {
+		defer c.Conn.SetInterrupt(old)
+	}
 
 	if !n.pragmas {
 		err = c.Conn.BusyTimeout(time.Minute)
@@ -362,8 +363,9 @@ func (c *conn) BeginTx(ctx context.Context, opts driver.TxOptions) (driver.Tx, e
 		c.txReset = `; PRAGMA query_only=` + string(c.readOnly)
 	}
 
-	old := c.Conn.SetInterrupt(ctx)
-	defer c.Conn.SetInterrupt(old)
+	if old := c.Conn.SetInterrupt(ctx); old != ctx {
+		defer c.Conn.SetInterrupt(old)
+	}
 
 	err := c.Conn.Exec(txBegin)
 	if err != nil {
@@ -382,8 +384,10 @@ func (c *conn) Commit() error {
 
 func (c *conn) Rollback() error {
 	// ROLLBACK even if interrupted.
-	old := c.Conn.SetInterrupt(context.Background())
-	defer c.Conn.SetInterrupt(old)
+	ctx := context.Background()
+	if old := c.Conn.SetInterrupt(ctx); old != ctx {
+		defer c.Conn.SetInterrupt(old)
+	}
 	return c.Conn.Exec(`ROLLBACK` + c.txReset)
 }
 
@@ -393,8 +397,9 @@ func (c *conn) Prepare(query string) (driver.Stmt, error) {
 }
 
 func (c *conn) PrepareContext(ctx context.Context, query string) (driver.Stmt, error) {
-	old := c.Conn.SetInterrupt(ctx)
-	defer c.Conn.SetInterrupt(old)
+	if old := c.Conn.SetInterrupt(ctx); old != ctx {
+		defer c.Conn.SetInterrupt(old)
+	}
 
 	s, tail, err := c.Conn.Prepare(query)
 	if err != nil {
@@ -419,8 +424,9 @@ func (c *conn) ExecContext(ctx context.Context, query string, args []driver.Name
 		return resultRowsAffected(0), nil
 	}
 
-	old := c.Conn.SetInterrupt(ctx)
-	defer c.Conn.SetInterrupt(old)
+	if old := c.Conn.SetInterrupt(ctx); old != ctx {
+		defer c.Conn.SetInterrupt(old)
+	}
 
 	err := c.Conn.Exec(query)
 	if err != nil {
@@ -483,8 +489,10 @@ func (s *stmt) ExecContext(ctx context.Context, args []driver.NamedValue) (drive
 		return nil, err
 	}
 
-	old := s.Stmt.Conn().SetInterrupt(ctx)
-	defer s.Stmt.Conn().SetInterrupt(old)
+	c := s.Stmt.Conn()
+	if old := c.SetInterrupt(ctx); old != ctx {
+		defer c.SetInterrupt(old)
+	}
 
 	err = errors.Join(
 		s.Stmt.Exec(),
@@ -493,7 +501,7 @@ func (s *stmt) ExecContext(ctx context.Context, args []driver.NamedValue) (drive
 		return nil, err
 	}
 
-	return newResult(s.Stmt.Conn()), nil
+	return newResult(c), nil
 }
 
 func (s *stmt) QueryContext(ctx context.Context, args []driver.NamedValue) (driver.Rows, error) {
@@ -678,13 +686,14 @@ func (r *rows) scanType(index int) scantype {
 
 func (r *rows) loadColumnMetadata() {
 	if r.nulls == nil {
+		c := r.Stmt.Conn()
 		count := r.Stmt.ColumnCount()
 		nulls := make([]bool, count)
 		types := make([]string, count)
 		scans := make([]scantype, count)
 		for i := range nulls {
 			if col := r.Stmt.ColumnOriginName(i); col != "" {
-				types[i], _, nulls[i], _, _, _ = r.Stmt.Conn().TableColumnMetadata(
+				types[i], _, nulls[i], _, _, _ = c.TableColumnMetadata(
 					r.Stmt.ColumnDatabaseName(i),
 					r.Stmt.ColumnTableName(i),
 					col)
@@ -762,8 +771,10 @@ func (r *rows) ColumnTypeScanType(index int) (typ reflect.Type) {
 }
 
 func (r *rows) Next(dest []driver.Value) error {
-	old := r.Stmt.Conn().SetInterrupt(r.ctx)
-	defer r.Stmt.Conn().SetInterrupt(old)
+	c := r.Stmt.Conn()
+	if old := c.SetInterrupt(r.ctx); old != r.ctx {
+		defer c.SetInterrupt(old)
+	}
 
 	if !r.Stmt.Step() {
 		if err := r.Stmt.Err(); err != nil {