Improve jwt_key validator

src/econf.erl

@@ -162,7 +162,7 @@ format_error({bad_cert, Why, Path}) ->
 format_error({bad_jwt_key, Path}) ->
     format("No valid JWT key found in file: ~ts", [Path]);
 format_error({bad_jwt_key_set, Path}) ->
-    format("JWT key contains JWK set in file: ~ts", [Path]);
+    format("JWK set contains multiple JWT keys in file: ~ts", [Path]);
 format_error({bad_jid, Bad}) ->
     format("Invalid XMPP address: ~ts", [Bad]);
 format_error({bad_user, Bad}) ->

src/ejabberd_options.erl

@@ -411,8 +411,10 @@ opt_type(jwt_key) ->
                               case jose_jwk:to_map(JWK) of
                                   {_, #{<<"keys">> := [Key]}} ->
                                       jose_jwk:from_map(Key);
-                                  {_, #{<<"keys">> := _}} ->
+                                  {_, #{<<"keys">> := [_|_]}} ->
                                       econf:fail({bad_jwt_key_set, Path});
+				  {_, #{<<"keys">> := _}} ->
+				      econf:fail({bad_jwt_key, Path});
                                   _ ->
                                       JWK
                               end