From 19baa213c5a69d4cd0fbe3e430a6c08a78e7acbb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Tue, 18 Jan 2011 16:56:04 +0100
Subject: Refuse to compile functions with too many arguments

---
 lib/stdlib/src/erl_lint.erl        | 22 +++++++++++++++++-----
 lib/stdlib/test/erl_lint_SUITE.erl | 22 +++++++++++++++++++---
 2 files changed, 36 insertions(+), 8 deletions(-)

(limited to 'lib/stdlib')

diff --git a/lib/stdlib/src/erl_lint.erl b/lib/stdlib/src/erl_lint.erl
index 0c2d3db8ec..cfb9f0ca98 100644
--- a/lib/stdlib/src/erl_lint.erl
+++ b/lib/stdlib/src/erl_lint.erl
@@ -2,7 +2,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 1996-2010. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2011. 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
@@ -60,6 +60,10 @@ value_option(Flag, Default, On, OnVal, Off, OffVal, Opts) ->
               (_Opt, Def) -> Def
           end, Default, Opts).
 
+%% The maximum number of arguments allowed for a function.
+
+-define(MAX_ARGUMENTS, 255).
+
 %% The error and warning info structures, {Line,Module,Descriptor},
 %% are kept in their seperate fields in the lint state record together
 %% with the name of the file (when a new file is entered, marked by
@@ -226,6 +230,9 @@ format_error({obsolete_guard, {F, A}}) ->
     io_lib:format("~p/~p obsolete", [F, A]);
 format_error({reserved_for_future,K}) ->
     io_lib:format("atom ~w: future reserved keyword - rename or quote", [K]);
+format_error({too_many_arguments,Arity}) ->
+    io_lib:format("too many arguments (~w) - "
+		  "maximum allowed is ~w", [Arity,?MAX_ARGUMENTS]);
 %% --- patterns and guards ---
 format_error(illegal_pattern) -> "illegal pattern";
 format_error(illegal_bin_pattern) ->
@@ -1307,13 +1314,18 @@ define_function(Line, Name, Arity, St0) ->
         true ->
             add_error(Line, {redefine_function,NA}, St1);
         false ->
-            St2 = St1#lint{defined=gb_sets:add_element(NA, St1#lint.defined)},
-            case imported(Name, Arity, St2) of
-                {yes,_M} -> add_error(Line, {define_import,NA}, St2);
-                no -> St2
+	    St2 = function_check_max_args(Line, Arity, St1),
+            St3 = St2#lint{defined=gb_sets:add_element(NA, St2#lint.defined)},
+            case imported(Name, Arity, St3) of
+                {yes,_M} -> add_error(Line, {define_import,NA}, St3);
+                no -> St3
             end
     end.
 
+function_check_max_args(Line, Arity, St) when Arity > ?MAX_ARGUMENTS ->
+    add_error(Line, {too_many_arguments,Arity}, St);
+function_check_max_args(_, _, St) -> St.
+
 %% clauses([Clause], VarTable, State) -> {VarTable, State}.
 
 clauses(Cs, Vt, St) ->
diff --git a/lib/stdlib/test/erl_lint_SUITE.erl b/lib/stdlib/test/erl_lint_SUITE.erl
index d0c0d68b4a..c4158abf32 100644
--- a/lib/stdlib/test/erl_lint_SUITE.erl
+++ b/lib/stdlib/test/erl_lint_SUITE.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 1999-2010. All Rights Reserved.
+%% Copyright Ericsson AB 1999-2011. 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
@@ -54,7 +54,8 @@
 	 otp_7550/1,
          otp_8051/1,
 	 format_warn/1,
-	 on_load/1, on_load_successful/1, on_load_failing/1
+	 on_load/1, on_load_successful/1, on_load_failing/1,
+	 too_many_arguments/1
         ]).
 
 % Default timetrap timeout (set in init_per_testcase).
@@ -77,7 +78,7 @@ all(suite) ->
      otp_5362, otp_5371, otp_7227, otp_5494, otp_5644, otp_5878, otp_5917, otp_6585,
      otp_6885, export_all, bif_clash,
      behaviour_basic, behaviour_multiple, otp_7550, otp_8051, format_warn,
-     on_load].
+     on_load,too_many_arguments].
 
 unused_vars_warn(suite) ->
     [unused_vars_warn_basic, unused_vars_warn_lc, unused_vars_warn_rec, 
@@ -2913,6 +2914,21 @@ on_load_failing(Config) when is_list(Config) ->
     ?line [] = run(Config, Ts),
     ok.
 
+too_many_arguments(doc) ->
+    "Test that too many arguments is not accepted.";
+too_many_arguments(suite) -> [];
+too_many_arguments(Config) when is_list(Config) ->
+    Ts = [{too_many_1,
+	   <<"f(_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_,_) -> ok.">>,
+	   [],
+	   {errors,
+	    [{1,erl_lint,{too_many_arguments,256}}],[]}}
+	 ],
+	  
+    ?line [] = run(Config, Ts),
+    ok.
+
+
 run(Config, Tests) ->
     F = fun({N,P,Ws,E}, BadL) ->
                 case catch run_test(Config, P, Ws) of
-- 
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