Bind erlang:get_stacktrace prior to making other calls

If we bind too late there might be an exception triggered
in the terminate function and we will not get the correct
stacktrace as a result.

src/cowboy_handler.erl

@@ -47,8 +47,9 @@ execute(Req, Env=#{handler := Handler, handler_opts := HandlerOpts}) ->
 		{Mod, Req2, State, Opts} ->
 			Mod:upgrade(Req2, Env, Handler, State, Opts)
 	catch Class:Reason ->
+		StackTrace = erlang:get_stacktrace(),
 		terminate({crash, Class, Reason}, Req, HandlerOpts, Handler),
-		erlang:raise(Class, Reason, erlang:get_stacktrace())
+		erlang:raise(Class, Reason, StackTrace)
 	end.
 
 -spec terminate(any(), Req | undefined, any(), module()) -> ok when Req::cowboy_req:req().

src/cowboy_loop.erl

@@ -82,8 +82,9 @@ call(Req0, Env, Handler, HandlerState0, Message) ->
 		{stop, Req, HandlerState} ->
 			terminate(Req, Env, Handler, HandlerState, stop)
 	catch Class:Reason ->
+		StackTrace = erlang:get_stacktrace(),
 		cowboy_handler:terminate({crash, Class, Reason}, Req0, HandlerState0, Handler),
-		erlang:raise(Class, Reason, erlang:get_stacktrace())
+		erlang:raise(Class, Reason, StackTrace)
 	end.
 
 suspend(Req, Env, Handler, HandlerState) ->

src/cowboy_rest.erl

@@ -1622,8 +1622,9 @@ switch_handler({switch_handler, Mod, Opts}, Req, #state{handler_state=HandlerSta
 
 -spec error_terminate(cowboy_req:req(), #state{}, atom(), any()) -> no_return().
 error_terminate(Req, #state{handler=Handler, handler_state=HandlerState}, Class, Reason) ->
+	StackTrace = erlang:get_stacktrace(),
 	cowboy_handler:terminate({crash, Class, Reason}, Req, HandlerState, Handler),
-	erlang:raise(Class, Reason, erlang:get_stacktrace()).
+	erlang:raise(Class, Reason, StackTrace).
 
 terminate(Req, #state{handler=Handler, handler_state=HandlerState}) ->
 	Result = cowboy_handler:terminate(normal, Req, HandlerState, Handler),

src/cowboy_websocket.erl

@@ -503,9 +503,10 @@ handler_call(State=#state{handler=Handler}, HandlerState,
 		{stop, HandlerState2} ->
 			websocket_close(State, HandlerState2, stop)
 	catch Class:Reason ->
+		StackTrace = erlang:get_stacktrace(),
 		websocket_send_close(State, {crash, Class, Reason}),
 		handler_terminate(State, HandlerState, {crash, Class, Reason}),
-		erlang:raise(Class, Reason, erlang:get_stacktrace())
+		erlang:raise(Class, Reason, StackTrace)
 	end.
 
 -spec handler_call_result(#state{}, any(), parse_state(), fun(), commands()) -> no_return().