refactor: remove lazy type for authentication

The idea of using lazy type for authentication was to make the
config check easy to extend at runtime. However the reality
is: it's overly complicated.

It's more likely that people will just continue to implementing
the auth hook callbacks instead of injecting config schema
at runtime.

apps/emqx/src/emqx_config.erl

@@ -366,13 +366,6 @@ schema_default(Schema) ->
     case hocon_schema:field_schema(Schema, type) of
         ?ARRAY(_) ->
             [];
-        ?LAZY(?ARRAY(_)) ->
-            [];
-        ?LAZY(?UNION(Members)) ->
-            case [A || ?ARRAY(A) <- hoconsc:union_members(Members)] of
-                [_ | _] -> [];
-                _ -> #{}
-            end;
         _ ->
             #{}
     end.
@@ -407,8 +400,7 @@ merge_envs(SchemaMod, RawConf) ->
     Opts = #{
         required => false,
         format => map,
-        apply_override_envs => true,
+        apply_override_envs => true
-        check_lazy => true
     },
     hocon_tconf:merge_env_overrides(SchemaMod, RawConf, all, Opts).
 
@@ -451,9 +443,7 @@ compact_errors(Schema, Errors) ->
 do_check_config(SchemaMod, RawConf, Opts0) ->
     Opts1 = #{
         return_plain => true,
-        format => map,
+        format => map
-        %% Don't check lazy types, such as authenticate
-        check_lazy => false
     },
     Opts = maps:merge(Opts0, Opts1),
     {AppEnvs, CheckedConf} =

apps/emqx/src/emqx_schema.erl

@@ -2352,25 +2352,18 @@ authentication(Which) ->
             global -> ?DESC(global_authentication);
             listener -> ?DESC(listener_authentication)
         end,
-    %% The runtime module injection
+    %% poor man's dependency injection
-    %% from EMQX_AUTHENTICATION_SCHEMA_MODULE_PT_KEY
+    %% this is due to the fact that authn is implemented outside of 'emqx' app.
-    %% is for now only affecting document generation.
+    %% so it can not be a part of emqx_schema since 'emqx' app is supposed to
-    %% maybe in the future, we can find a more straightforward way to support
+    %% work standalone.
-    %% * document generation (at compile time)
+    Type =
-    %% * type checks before boot (in bin/emqx config generation)
-    %% * type checks at runtime (when changing configs via management API)
-    Type0 =
         case persistent_term:get(?EMQX_AUTHENTICATION_SCHEMA_MODULE_PT_KEY, undefined) of
-            undefined -> hoconsc:array(typerefl:map());
+            undefined ->
-            Module -> Module:root_type()
+                hoconsc:array(typerefl:map());
+            Module ->
+                Module:root_type()
         end,
-    %% It is a lazy type because when handling runtime update requests
+    hoconsc:mk(Type, #{desc => Desc}).
-    %% the config is not checked by emqx_schema, but by the injected schema
-    Type = hoconsc:lazy(Type0),
-    #{
-        type => Type,
-        desc => Desc
-    }.
 
 -spec qos() -> typerefl:type().
 qos() ->

apps/emqx_conf/src/emqx_conf.erl

@@ -296,8 +296,6 @@ hocon_schema_to_spec(Type, LocalModule) when ?IS_TYPEREFL(Type) ->
 hocon_schema_to_spec(?ARRAY(Item), LocalModule) ->
     {Schema, Refs} = hocon_schema_to_spec(Item, LocalModule),
     {#{type => array, items => Schema}, Refs};
-hocon_schema_to_spec(?LAZY(Item), LocalModule) ->
-    hocon_schema_to_spec(Item, LocalModule);
 hocon_schema_to_spec(?ENUM(Items), _LocalModule) ->
     {#{type => enum, symbols => Items}, []};
 hocon_schema_to_spec(?MAP(Name, Type), LocalModule) ->

apps/emqx_dashboard/src/emqx_dashboard_swagger.erl

@@ -609,8 +609,6 @@ hocon_schema_to_spec(Type, LocalModule) when ?IS_TYPEREFL(Type) ->
 hocon_schema_to_spec(?ARRAY(Item), LocalModule) ->
     {Schema, Refs} = hocon_schema_to_spec(Item, LocalModule),
     {#{type => array, items => Schema}, Refs};
-hocon_schema_to_spec(?LAZY(Item), LocalModule) ->
-    hocon_schema_to_spec(Item, LocalModule);
 hocon_schema_to_spec(?ENUM(Items), _LocalModule) ->
     {#{type => string, enum => Items}, []};
 hocon_schema_to_spec(?MAP(Name, Type), LocalModule) ->