Also format gracefully errors returned during module reload

diff --git a/src/gen_mod.erl b/src/gen_mod.erl
index 456afca07a830f973c646f7f67a953b4eb0bedcf..a30cc54626a96030227fc2da80dda028cc940b03 100644 (file)
--- a/src/gen_mod.erl
+++ b/src/gen_mod.erl
@@ -220,13 +220,15 @@ start_module(Host, Module, Opts0, Order, NeedValidation) ->
                    Err -> erlang:error({bad_return, Module, Err})
                end
            catch Class:Reason ->
+                   StackTrace = erlang:get_stacktrace(),
                    ets:delete(ejabberd_modules, {Module, Host}),
-                   ErrorText = format_start_error(
-                                 Module, Opts, Class, Reason,
-                                 erlang:get_stacktrace()),
+                   ErrorText = format_module_error(
+                                 Module, start, 2,
+                                 Opts, Class, Reason,
+                                 StackTrace),
                    ?CRITICAL_MSG(ErrorText, []),
                    maybe_halt_ejabberd(),
-                   erlang:raise(Class, Reason, erlang:get_stacktrace())
+                   erlang:raise(Class, Reason, StackTrace)
            end;
        {error, _ErrorText} ->
            maybe_halt_ejabberd()
@@ -280,14 +282,15 @@ reload_module(Host, Module, NewOpts, OldOpts, Order) ->
            try case Module:reload(Host, NewOpts, OldOpts) of
                    ok -> ok;
                    {ok, Pid} when is_pid(Pid) -> {ok, Pid};
-                   Err -> erlang:error(Err)
+                   Err -> erlang:error({bad_return, Module, Err})
                end
            catch Class:Reason ->
                    StackTrace = erlang:get_stacktrace(),
-                   ?CRITICAL_MSG("Failed to reload module ~s at ~s:~n"
-                                 "** Reason = ~p",
-                                 [Module, Host,
-                                  {Class, {Reason, StackTrace}}]),
+                   ErrorText = format_module_error(
+                                  Module, reload, 3,
+                                  NewOpts, Class, Reason,
+                                 StackTrace),
+                    ?CRITICAL_MSG(ErrorText, []),
                    erlang:raise(Class, Reason, StackTrace)
            end;
        false ->
@@ -707,38 +710,39 @@ get_submodules(Host, Module, Opts) ->
            []
     end.
 
--spec format_start_error(atom(), opts(),
-                        error | exit | throw, any(),
-                        [erlang:stack_item()]) -> iolist().
-format_start_error(Module, Opts, Class, Reason, St) ->
+-spec format_module_error(atom(), start | reload, non_neg_integer(), opts(),
+                         error | exit | throw, any(),
+                         [erlang:stack_item()]) -> iolist().
+format_module_error(Module, Fun, Arity, Opts, Class, Reason, St) ->
     IsLoaded = code:ensure_loaded(Module) == {module, Module},
-    IsStartExported = erlang:function_exported(Module, start, 2),
+    IsCallbackExported = erlang:function_exported(Module, Fun, Arity),
     case {Class, Reason} of
        {error, undef} when not IsLoaded ->
-           io_lib:format("Failed to load unknown module ~s: "
+           io_lib:format("Failed to ~s unknown module ~s: "
                          "make sure there is no typo and ~s.beam "
                          "exists inside either ~s or ~s "
                          "directory",
-                         [Module, Module,
+                         [Fun, Module, Module,
                           filename:dirname(code:which(?MODULE)),
                           ext_mod:modules_dir()]);
-       {error, undef} when not IsStartExported ->
-           io_lib:format("Failed to load module ~s because "
-                         "it doesn't export start/2 callback: "
-                         "is it really an ejabberd module?", [Module]);
+       {error, undef} when not IsCallbackExported ->
+           io_lib:format("Failed to ~s module ~s because "
+                         "it doesn't export ~s/~B callback: "
+                         "is it really an ejabberd module?",
+                         [Fun, Module, Fun, Arity]);
        {error, {bad_return, Module, Ret}} ->
-           io_lib:format("Module ~s returned unexpected value during "
-                         "startup: ~p; this is either not an ejabberd "
+           io_lib:format("Module ~s returned unexpected value from "
+                         "~s/~B: ~p; this is either not an ejabberd "
                          "module or it implements ejabbed API incorrectly",
-                         [Module, Ret]);
+                         [Module, Fun, Arity, Ret]);
        _ ->
            io_lib:format("Internal error of module ~s has "
-                         "occured during startup:~n"
+                         "occured during ~s:~n"
                          "** Options: ~p~n"
                          "** Class: ~p~n"
                          "** Reason: ~p~n"
                          "** Stacktrace: ~p",
-                         [Module, Opts, Class, Reason, St])
+                         [Module, Fun, Opts, Class, Reason, St])
     end.
 
 -spec db_type(binary() | global, module()) -> db_type();