imp(statemachine)!: check if there are duplicate client types in allo…

…wed clients param

Co-authored-by: Carlos Rodriguez <carlos@interchain.io>

modules/core/02-client/types/params.go

@@ -33,12 +33,17 @@ func (p Params) IsAllowedClient(clientType string) bool {
 	return slices.Contains(p.AllowedClients, clientType)
 }
 
-// validateClients checks that the given clients are not blank.
+// validateClients checks that the given clients are not blank and there are no duplicates.
 func validateClients(clients []string) error {
+	foundClients := make(map[string]bool, len(clients))
 	for i, clientType := range clients {
 		if strings.TrimSpace(clientType) == "" {
 			return fmt.Errorf("client type %d cannot be blank", i)
 		}
+		if foundClients[clientType] {
+			return fmt.Errorf("duplicate client type: %s", clientType)
+		}
+		foundClients[clientType] = true
 	}
 
 	return nil

modules/core/02-client/types/params_test.go

@@ -36,6 +36,7 @@ func TestValidateParams(t *testing.T) {
 		{"default params", DefaultParams(), true},
 		{"custom params", NewParams(exported.Tendermint), true},
 		{"blank client", NewParams(" "), false},
+		{"duplicate clients", NewParams(exported.Tendermint, exported.Tendermint), false},
 	}
 
 	for _, tc := range testCases {