Fix get_env bug

src/lager_app.erl

@@ -138,11 +138,10 @@ maybe_install_sink_killer(_Sink, HWM, ReinstallTimer) ->
     error_logger:error_msg("Invalid value for 'killer_hwm': ~p or 'killer_reinstall_after': ~p", [HWM, ReinstallTimer]),
     throw({error, bad_config}).
 
-start_error_logger_handler({ok, false}, _HWM, _Whitelist) ->
+-spec start_error_logger_handler(boolean(), pos_integer(), list()) -> list().
+start_error_logger_handler(false, _HWM, _Whitelist) ->
     [];
-start_error_logger_handler(_, HWM, undefined) ->
-    start_error_logger_handler(ignore_me, HWM, {ok, []});
-start_error_logger_handler(_, HWM, {ok, WhiteList}) ->
+start_error_logger_handler(true, HWM, WhiteList) ->
     GlStrategy = case application:get_env(lager, error_logger_groupleader_strategy) of
                     undefined ->
                         handle;
@@ -200,13 +199,16 @@ configure_extra_sinks(Sinks) ->
     lists:foreach(fun({Sink, Proplist}) -> configure_sink(Sink, Proplist) end,
                   Sinks).
 
+-spec get_env(atom(), atom()) -> term().
 get_env(Application, Key) ->
     get_env(Application, Key, undefined).
+
 %% R15 doesn't know about application:get_env/3
+-spec get_env(atom(), atom(), term()) -> term().
 get_env(Application, Key, Default) ->
-    get_env_default(application:get_env(Application, Key),
-                    Default).
+    get_env_default(application:get_env(Application, Key), Default).
 
+-spec get_env_default('undefined' | {'ok', term()}, term()) -> term().
 get_env_default(undefined, Default) ->
     Default;
 get_env_default({ok, Value}, _Default) ->
@@ -235,9 +237,9 @@ boot() ->
     lager:update_loglevel_config(?DEFAULT_SINK),
 
     SavedHandlers = start_error_logger_handler(
-                      get_env(lager, error_logger_redirect),
-                      interpret_hwm(get_env(lager, error_logger_hwm)),
-                      get_env(lager, error_logger_whitelist)
+                                    get_env(lager, error_logger_redirect, true),
+                      interpret_hwm(get_env(lager, error_logger_hwm, 0)),
+                                    get_env(lager, error_logger_whitelist, [])
                      ),
 
     SavedHandlers.