fix: unsubscribes and redundant methods

op-challenger/challenger/challenger.go

@@ -65,7 +65,7 @@ func (c *Challenger) Client() *ethclient.Client {
 }
 
 func (c *Challenger) NewOracleSubscription() (*Subscription, error) {
-	query, err := c.BuildOutputLogFilter()
+	query, err := BuildOutputLogFilter(c.l2ooABI)
 	if err != nil {
 		return nil, err
 	}

op-challenger/challenger/oracle.go

@@ -34,8 +34,3 @@ func BuildOutputLogFilter(l2ooABI *abi.ABI) (ethereum.FilterQuery, error) {
 
 	return query, nil
 }
-
-// BuildOutputLogFilter creates a filter query for the L2OutputOracle contract.
-func (c *Challenger) BuildOutputLogFilter() (ethereum.FilterQuery, error) {
-	return BuildOutputLogFilter(c.l2ooABI)
-}

op-challenger/cmd/watch/oracle.go

@@ -41,6 +41,8 @@ func Oracle(logger log.Logger, cfg *config.Config) error {
 		return err
 	}
 
+	defer subscription.Quit()
+
 	interruptChannel := make(chan os.Signal, 1)
 	signal.Notify(interruptChannel, []os.Signal{
 		os.Interrupt,