fix(tpl): rename `trivial` -> `is_const`

This is clearer. Former naming was a bit misleading.

apps/emqx_auth/src/emqx_authz/emqx_authz_rule.erl

@@ -184,7 +184,7 @@ compile_topic({eq, Topic}) ->
     {eq, emqx_topic:words(bin(Topic))};
 compile_topic(Topic) ->
     Template = emqx_authz_utils:parse_str(Topic, [?VAR_USERNAME, ?VAR_CLIENTID]),
-    case emqx_connector_template:trivial(Template) of
+    case emqx_connector_template:is_const(Template) of
         true -> emqx_topic:words(bin(Topic));
         false -> {pattern, Template}
     end.

apps/emqx_connector/src/emqx_connector_template.erl

@@ -23,7 +23,7 @@
 -export([parse_deep/1]).
 -export([parse_deep/2]).
 -export([validate/2]).
--export([trivial/1]).
+-export([is_const/1]).
 -export([unparse/1]).
 -export([render/2]).
 -export([render/3]).
@@ -124,7 +124,6 @@ parse_accessor(Var) ->
         [<<>>] ->
             ?PH_VAR_THIS;
         Name ->
-            % TODO: lowercase?
             Name
     end.
 
@@ -140,9 +139,11 @@ validate(Allowed, Template) ->
             {error, [{Var, disallowed} || Var <- Disallowed]}
     end.
 
--spec trivial(t()) ->
+%% @doc Check if a template is constant with respect to rendering, i.e. does not
+%% contain any placeholders.
+-spec is_const(t()) ->
     boolean().
-trivial(Template) ->
+is_const(Template) ->
     validate([], Template) == ok.
 
 -spec unparse(t()) ->

apps/emqx_connector/test/emqx_connector_template_SUITE.erl

@@ -122,18 +122,18 @@ t_unparse(_) ->
         unicode:characters_to_binary(emqx_connector_template:unparse(Template))
     ).
 
-t_trivial(_) ->
+t_const(_) ->
     ?assertEqual(
         true,
-        emqx_connector_template:trivial(emqx_connector_template:parse(<<"">>))
+        emqx_connector_template:is_const(emqx_connector_template:parse(<<"">>))
     ),
     ?assertEqual(
         false,
-        emqx_connector_template:trivial(emqx_connector_template:parse(<<"a:${a},b:${b},c:$${c}">>))
+        emqx_connector_template:is_const(emqx_connector_template:parse(<<"a:${a},b:${b},c:$${c}">>))
     ),
     ?assertEqual(
         true,
-        emqx_connector_template:trivial(
+        emqx_connector_template:is_const(
             emqx_connector_template:parse(<<"a:$${a},b:$${b},c:$${c}">>)
         )
     ).