Teach error_handler to call '$handle_undefined_function'

4 files changed, 119 insertions, 41 deletions

diff --git a/lib/kernel/doc/src/error_handler.xml b/lib/kernel/doc/src/error_handler.xml
index acbf9a2c6e..610b65f0a2 100644
--- a/lib/kernel/doc/src/error_handler.xml
+++ b/lib/kernel/doc/src/error_handler.xml
@@ -43,19 +43,39 @@
         A (possibly empty) list of arguments <c>Arg1,..,ArgN</c>
       </type_desc>
       <desc>
-        <p>This function is evaluated if a call is made to
+        <p>This function is called by the run-time system if a call is made to
           <c><anno>Module</anno>:<anno>Function</anno>(Arg1,.., ArgN)</c> and
           <c><anno>Module</anno>:<anno>Function</anno>/N</c> is undefined. Note that
           <c>undefined_function/3</c> is evaluated inside the process
           making the original call.</p>
-        <p>If <c><anno>Module</anno></c> is interpreted, the interpreter is invoked
-          and the return value of the interpreted
-          <c><anno>Function</anno>(Arg1,.., ArgN)</c> call is returned.</p>
-        <p>Otherwise, it returns, if possible, the value of
-          <c>apply(<anno>Module</anno>, <anno>Function</anno>, <anno>Args</anno>)</c> after an attempt has been
-          made to autoload <c><anno>Module</anno></c>. If this is not possible, the
-          call to <c><anno>Module</anno>:<anno>Function</anno>(Arg1,.., ArgN)</c> fails with
-          exit reason <c>undef</c>.</p>
+
+	<p>This function will first attempt to autoload
+	  <c><anno>Module</anno></c>. If that is not possible,
+	  an <c>undef</c> exception will be raised.</p>
+
+	<p>If it was possible to load <c><anno>Module</anno></c>
+	  and the function <c><anno>Function</anno>/N</c> is exported,
+	  it will be called.</p>
+
+	<p>Otherwise, if the function <c>'$handle_undefined_function'/2</c>
+	  is exported, it will be called as
+          <c>'$handle_undefined_function'(</c><anno>Function</anno>,
+	  <anno>Args</anno>).
+	</p>
+	<p>Otherwise an <c>undef</c> exception will be raised.</p>
+      </desc>
+    </func>
+    <func>
+      <name name="raise_undef_exception" arity="3"/>
+      <fsummary>Raise an undef exception</fsummary>
+      <type_desc variable="Args">
+        A (possibly empty) list of arguments <c>Arg1,..,ArgN</c>
+      </type_desc>
+      <desc>
+	<p>Raise an <c>undef</c> exception with a stacktrace indicating
+	that <c><anno>Module</anno>:<anno>Function</anno>/N</c> is
+	undefined.
+	</p>
       </desc>
     </func>
     <func>
diff --git a/lib/kernel/src/error_handler.erl b/lib/kernel/src/error_handler.erl
index f8bc5f499c..a3aa1f1dcf 100644
--- a/lib/kernel/src/error_handler.erl
+++ b/lib/kernel/src/error_handler.erl
@@ -23,10 +23,12 @@
 %% "error_handler: add no_native compiler directive"
 -compile(no_native).
 
-%% A simple error handler.
+%% Callbacks called from the run-time system.
+-export([undefined_function/3,undefined_lambda/3,breakpoint/3]).
 
--export([undefined_function/3, undefined_lambda/3, stub_function/3,
-	 breakpoint/3]).
+%% Exported utility functions.
+-export([raise_undef_exception/3]).
+-export([stub_function/3]).
 
 -spec undefined_function(Module, Function, Args) ->
 	any() when
@@ -41,12 +43,7 @@ undefined_function(Module, Func, Args) ->
 		true ->
 		    apply(Module, Func, Args);
 		false ->
-		    case check_inheritance(Module, Args) of
-			{value, Base, Args1} ->
-			    apply(Base, Func, Args1);
-			none ->
-			    crash(Module, Func, Args)
-		    end
+		    call_undefined_function_handler(Module, Func, Args)
 	    end;
 	{module, _} ->
 	    crash(Module, Func, Args);
@@ -77,6 +74,14 @@ undefined_lambda(Module, Fun, Args) ->
 breakpoint(Module, Func, Args) ->
     (int()):eval(Module, Func, Args).
 
+-spec raise_undef_exception(Module, Function, Args) -> no_return() when
+      Module :: atom(),
+      Function :: atom(),
+      Args :: list().
+
+raise_undef_exception(Module, Func, Args) ->
+    crash({Module,Func,Args,[]}).
+
 %% Used to make the call to the 'int' module a "weak" one, to avoid
 %% building strong components in xref or dialyzer.
 
@@ -130,27 +135,11 @@ ensure_loaded(Module) ->
 stub_function(Mod, Func, Args) ->
     exit({undef,[{Mod,Func,Args,[]}]}).
 
-check_inheritance(Module, Args) ->
-    Attrs = erlang:get_module_info(Module, attributes),
-    case lists:keyfind(extends, 1, Attrs) of
-	{extends, [Base]} when is_atom(Base), Base =/= Module ->
-	    %% This is just a heuristic for detecting abstract modules
-	    %% with inheritance so they can be handled; it would be
-	    %% much better to do it in the emulator runtime
-	    case lists:keyfind(abstract, 1, Attrs) of
-		{abstract, [true]} ->
-		    case lists:reverse(Args) of
-			[M|Rs] when tuple_size(M) > 1,
-			element(1,M) =:= Module,
-			tuple_size(element(2,M)) > 0,
-			is_atom(element(1,element(2,M))) ->
-			    {value, Base, lists:reverse(Rs, [element(2,M)])};
-			_ ->
-			    {value, Base, Args}
-		    end;
-		_ ->
-		    {value, Base, Args}
-	    end;
-	_ ->
-	    none
+call_undefined_function_handler(Module, Func, Args) ->
+    Handler = '$handle_undefined_function',
+    case erlang:function_exported(Module, Handler, 2) of
+	false ->
+	    crash(Module, Func, Args);
+	true ->
+	    Module:Handler(Func, Args)
     end.
diff --git a/lib/kernel/test/Makefile b/lib/kernel/test/Makefile
index 7fd3afe93c..8d2d55777b 100644
--- a/lib/kernel/test/Makefile
+++ b/lib/kernel/test/Makefile
@@ -48,6 +48,7 @@ MODULES= \
 	erl_distribution_SUITE \
 	erl_distribution_wb_SUITE \
 	erl_prim_loader_SUITE \
+	error_handler_SUITE \
 	error_logger_SUITE \
 	error_logger_warn_SUITE \
 	file_SUITE \
diff --git a/lib/kernel/test/error_handler_SUITE.erl b/lib/kernel/test/error_handler_SUITE.erl
new file mode 100644
index 0000000000..2a86d39b74
--- /dev/null
+++ b/lib/kernel/test/error_handler_SUITE.erl
@@ -0,0 +1,68 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2013. All Rights Reserved.
+%%
+%% The contents of this file are subject to the Erlang Public License,
+%% Version 1.1, (the "License"); you may not use this file except in
+%% compliance with the License. You should have received a copy of the
+%% Erlang Public License along with this software. If not, it can be
+%% retrieved online at http://www.erlang.org/.
+%%
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and limitations
+%% under the License.
+%%
+%% %CopyrightEnd%
+%%
+-module(error_handler_SUITE).
+
+-export([all/0,suite/0,groups/0,init_per_suite/1,end_per_suite/1,
+	 init_per_group/2,end_per_group/2,
+	 undefined_function_handler/1]).
+
+%% Callback from error_handler.
+-export(['$handle_undefined_function'/2]).
+
+suite() -> [{ct_hooks,[ts_install_cth]}].
+
+all() ->
+    [undefined_function_handler].
+
+groups() ->
+    [].
+
+init_per_suite(Config) ->
+    Config.
+
+end_per_suite(_Config) ->
+    ok.
+
+init_per_group(_GroupName, Config) ->
+    Config.
+
+end_per_group(_GroupName, Config) ->
+    Config.
+
+
+%%-----------------------------------------------------------------
+
+undefined_function_handler(_) ->
+    42 = ?MODULE:forty_two(),
+    42 = (id(?MODULE)):forty_two(),
+    {ok,{a,b,c}} = ?MODULE:one_arg({a,b,c}),
+    {ok,{a,b,c}} = (id(?MODULE)):one_arg({a,b,c}),
+    {'EXIT',{undef,[{?MODULE,undef_and_not_handled,[[1,2,3]],[]}|_]}} =
+	(catch ?MODULE:undef_and_not_handled([1,2,3])),
+    ok.
+
+'$handle_undefined_function'(forty_two, []) ->
+    42;
+'$handle_undefined_function'(one_arg, [Arg]) ->
+    {ok,Arg};
+'$handle_undefined_function'(Func, Args) ->
+    error_handler:raise_undef_exception(?MODULE, Func, Args).
+
+id(I) ->
+    I.