[logger] Start using handler callback changing_config/3 in built-in handlers

The new parameter to this function, SetOrUpdate, indicates how
unspecified configuration data fields shall be set. The rule is that
if SetOrUpdate equals set, then default values shall be used, and if
SetOrUpdate equals update, then existing configuration values shall be
used. Consequently, these examples now apply to logger_std_h and
logger_disk_log_h:

set_handler_config(default, config, #{sync_mode_qlen => 20}) sets the
value of sync_mode_qlen to 20, and resets all other (writable) fields
in the config map to their default values.

update_handler_config(default, config, #{sync_mode_qlen => 20}) sets
the value of sync_mode_qlen to 20, and leaves all other fields in the
config map unchanged.

1 files changed, 12 insertions, 0 deletions

diff --git a/lib/kernel/test/logger_SUITE.erl b/lib/kernel/test/logger_SUITE.erl
index b7ccba8e70..d831d0d108 100644
--- a/lib/kernel/test/logger_SUITE.erl
+++ b/lib/kernel/test/logger_SUITE.erl
@@ -246,6 +246,18 @@ change_config(_Config) ->
     {ok,C4} = logger:get_handler_config(h1),
     C4 = C3#{custom:=new_custom},
 
+    %% Change handler config: Id and module can not be changed
+    {error,{illegal_config_change,Old,New}} =
+        logger:set_handler_config(h1,id,newid),
+    %% Check that only the faulty field is included in return
+    [{id,h1}] = maps:to_list(Old),
+    [{id,newid}] = maps:to_list(New),
+    %% Check that both fields are included when both are changed
+    {error,{illegal_config_change,
+            #{id:=h1,module:=?MODULE},
+            #{id:=newid,module:=newmodule}}} =
+        logger:set_handler_config(h1,#{id=>newid,module=>newmodule}),
+
     %% Change primary config: Single key
     PConfig0 = logger:get_primary_config(),
     ok = logger:set_primary_config(level,warning),