stdlib: Correct maps module exceptions upon errors

Bad input to maps module function will now yield exceptions:
  * {badmap,NotMap} or,
  * badarg

2 files changed, 99 insertions, 35 deletions

diff --git a/lib/stdlib/src/maps.erl b/lib/stdlib/src/maps.erl
index ba4d6a5c87..3877c150ec 100644
--- a/lib/stdlib/src/maps.erl
+++ b/lib/stdlib/src/maps.erl
@@ -19,31 +19,15 @@
 
 -module(maps).
 
--export([
-	fold/3,
-	map/2,
-	size/1,
-    without/2,
-    with/2,
-    get/3
-    ]).
+-export([get/3,fold/3, map/2, size/1,
+         without/2, with/2]).
 
 
 %%% BIFs
--export([
-	get/2,
-	find/2,
-	from_list/1,
-	is_key/2,
-	keys/1,
-	merge/2,
-	new/0,
-	put/3,
-	remove/2,
-	to_list/1,
-	update/3,
-	values/1
-    ]).
+-export([get/2, find/2, from_list/1,
+         is_key/2, keys/1, merge/2,
+         new/0, put/3, remove/2,
+         to_list/1, update/3, values/1]).
 
 -spec get(Key,Map) -> Value when
     Key :: term(),
@@ -150,13 +134,15 @@ values(_) -> erlang:nif_error(undef).
         Value :: term(),
         Default :: term().
 
-get(Key, Map, Default) ->
+get(Key,Map,Default) when is_map(Map) ->
     case maps:find(Key, Map) of
         {ok, Value} ->
             Value;
         error ->
             Default
-    end.
+    end;
+get(Key,Map,Default) ->
+    erlang:error({badmap,Map},[Key,Map,Default]).
 
 
 -spec fold(Fun,Init,Map) -> Acc when
@@ -169,8 +155,10 @@ get(Key, Map, Default) ->
     K :: term(),
     V :: term().
 
-fold(Fun, Init, Map) when is_function(Fun,3), is_map(Map) ->
-    lists:foldl(fun({K,V},A) -> Fun(K,V,A) end,Init,maps:to_list(Map)).
+fold(Fun,Init,Map) when is_function(Fun,3), is_map(Map) ->
+    lists:foldl(fun({K,V},A) -> Fun(K,V,A) end,Init,maps:to_list(Map));
+fold(Fun,Init,Map) ->
+    erlang:error(error_type(Map),[Fun,Init,Map]).
 
 -spec map(Fun,Map1) -> Map2 when
     Fun :: fun((K, V1) -> V2),
@@ -180,18 +168,22 @@ fold(Fun, Init, Map) when is_function(Fun,3), is_map(Map) ->
     V1 :: term(),
     V2 :: term().
 
-map(Fun, Map) when is_function(Fun, 2), is_map(Map) ->
+map(Fun,Map) when is_function(Fun, 2), is_map(Map) ->
     maps:from_list(lists:map(fun
 		({K,V}) ->
 		    {K,Fun(K,V)}
-	    end,maps:to_list(Map))).
+	    end,maps:to_list(Map)));
+map(Fun,Map) ->
+    erlang:error(error_type(Map),[Fun,Map]).
 
 
 -spec size(Map) -> non_neg_integer() when
     Map :: map().
 
 size(Map) when is_map(Map) ->
-    erlang:map_size(Map).
+    erlang:map_size(Map);
+size(Val) ->
+    erlang:error({badmap,Val},[Val]).
 
 
 -spec without(Ks,Map1) -> Map2 when
@@ -200,8 +192,10 @@ size(Map) when is_map(Map) ->
     Map2 :: map(),
     K :: term().
 
-without(Ks, M) when is_list(Ks), is_map(M) ->
-    maps:from_list([{K,V}||{K,V} <- maps:to_list(M), not lists:member(K, Ks)]).
+without(Ks,M) when is_list(Ks), is_map(M) ->
+    maps:from_list([{K,V}||{K,V} <- maps:to_list(M), not lists:member(K, Ks)]);
+without(Ks,M) ->
+    erlang:error(error_type(M),[Ks,M]).
 
 
 -spec with(Ks, Map1) -> Map2 when
@@ -210,5 +204,11 @@ without(Ks, M) when is_list(Ks), is_map(M) ->
     Map2 :: map(),
     K :: term().
 
-with(Ks, M) when is_list(Ks), is_map(M) ->
-    maps:from_list([{K,V}||{K,V} <- maps:to_list(M), lists:member(K, Ks)]).
+with(Ks,M) when is_list(Ks), is_map(M) ->
+    maps:from_list([{K,V}||{K,V} <- maps:to_list(M), lists:member(K, Ks)]);
+with(Ks,M) ->
+    erlang:error(error_type(M),[Ks,M]).
+
+
+error_type(M) when is_map(M) -> badarg;
+error_type(V) -> {badmap, V}.
diff --git a/lib/stdlib/test/maps_SUITE.erl b/lib/stdlib/test/maps_SUITE.erl
index dda20a615b..1d9c041a74 100644
--- a/lib/stdlib/test/maps_SUITE.erl
+++ b/lib/stdlib/test/maps_SUITE.erl
@@ -34,13 +34,20 @@
 -export([init_per_testcase/2]).
 -export([end_per_testcase/2]).
 
--export([t_get_3/1,t_with_2/1,t_without_2/1]).
+-export([t_get_3/1,
+         t_fold_3/1,t_map_2/1,t_size_1/1,
+         t_with_2/1,t_without_2/1]).
+
+-define(badmap(V,F,Args), {'EXIT', {{badmap,V}, [{maps,F,Args,_}|_]}}).
+-define(badarg(F,Args), {'EXIT', {badarg, [{maps,F,Args,_}|_]}}).
 
 suite() ->
     [{ct_hooks, [ts_install_cth]}].
 
 all() ->
-    [t_get_3,t_with_2,t_without_2].
+    [t_get_3,
+     t_fold_3,t_map_2,t_size_1,
+     t_with_2,t_without_2].
 
 init_per_suite(Config) ->
     Config.
@@ -63,6 +70,9 @@ t_get_3(Config) when is_list(Config) ->
     value1 = maps:get(key1, Map, DefaultValue),
     value2 = maps:get(key2, Map, DefaultValue),
     DefaultValue = maps:get(key3, Map, DefaultValue),
+
+    %% error case
+    ?badmap(a,get,[[a,b],a,def]) = (catch maps:get([a,b],id(a),def)),
     ok.
 
 t_without_2(_Config) ->
@@ -70,6 +80,11 @@ t_without_2(_Config) ->
     M0 = maps:from_list([{{k,I},{v,I}}||I<-lists:seq(1,100)]),
     M1 = maps:from_list([{{k,I},{v,I}}||I<-lists:seq(1,100) -- Ki]),
     M1 = maps:without([{k,I}||I <- Ki],M0),
+
+    %% error case
+    ?badmap(a,without,[[a,b],a]) = (catch maps:without([a,b],id(a))),
+    ?badmap(a,without,[{a,b},a]) = (catch maps:without({a,b},id(a))),
+    ?badarg(without,[a,#{}]) = (catch maps:without(a,#{})),
     ok.
 
 t_with_2(_Config) ->
@@ -77,4 +92,53 @@ t_with_2(_Config) ->
     M0 = maps:from_list([{{k,I},{v,I}}||I<-lists:seq(1,100)]),
     M1 = maps:from_list([{{k,I},{v,I}}||I<-Ki]),
     M1 = maps:with([{k,I}||I <- Ki],M0),
+
+    %% error case
+    ?badmap(a,with,[[a,b],a]) = (catch maps:with([a,b],id(a))),
+    ?badmap(a,with,[{a,b},a]) = (catch maps:with({a,b},id(a))),
+    ?badarg(with,[a,#{}]) = (catch maps:with(a,#{})),
+    ok.
+
+
+t_fold_3(Config) when is_list(Config) ->
+    Vs = lists:seq(1,200),
+    M0 = maps:from_list([{{k,I},I}||I<-Vs]),
+    #{ {k,1} := 1, {k,200} := 200} = M0,
+    Tot0 = lists:sum(Vs),
+    Tot1 = maps:fold(fun({k,_},V,A) -> A + V end, 0, M0),
+    true = Tot0 =:= Tot1,
+
+    %% error case
+    ?badmap(a,fold,[_,0,a]) = (catch maps:fold(fun(_,_,_) -> ok end,0,id(a))),
+    ?badarg(fold,[<<>>,0,#{}]) = (catch maps:fold(id(<<>>),0,#{})),
     ok.
+
+t_map_2(Config) when is_list(Config) ->
+    Vs = lists:seq(1,200),
+    M0 = maps:from_list([{{k,I},I}||I<-Vs]),
+    #{ {k,1} := 1, {k,200} := 200} = M0,
+    M1 = maps:map(fun({k,_},V) -> V + 42 end, M0),
+    #{ {k,1} := 43, {k,200} := 242} = M1,
+
+    %% error case
+    ?badmap(a,map,[_,a]) = (catch maps:map(fun(_,_) -> ok end, id(a))),
+    ?badarg(map,[<<>>,#{}]) = (catch maps:map(id(<<>>),#{})),
+    ok.
+
+
+t_size_1(Config) when is_list(Config) ->
+      0 = maps:size(#{}),
+     10 = maps:size(maps:from_list([{{"k",I},I}||I<-lists:seq(1,10)])),
+     20 = maps:size(maps:from_list([{{"k",I},I}||I<-lists:seq(1,20)])),
+     30 = maps:size(maps:from_list([{{"k",I},I}||I<-lists:seq(1,30)])),
+     40 = maps:size(maps:from_list([{{"k",I},I}||I<-lists:seq(1,40)])),
+     50 = maps:size(maps:from_list([{{"k",I},I}||I<-lists:seq(1,50)])),
+     60 = maps:size(maps:from_list([{{"k",I},I}||I<-lists:seq(1,60)])),
+    600 = maps:size(maps:from_list([{{"k",I},I}||I<-lists:seq(1,600)])),
+
+    %% error case
+    ?badmap(a,size,[a]) = (catch maps:size(id(a))),
+    ?badmap(<<>>,size,[<<>>]) = (catch maps:size(id(<<>>))),
+    ok.
+
+id(I) -> I.