Raise more descriptive error messages for failed map operations

According to EEP-43 for maps, a 'badmap' exception should be
generated when an attempt is made to update non-map term such as:

   <<>>#{a=>42}

That was not implemented in the OTP 17.

José Valim suggested that we should take the opportunity to
improve the errors coming from map operations:

  http://erlang.org/pipermail/erlang-questions/2015-February/083588.html

This commit implement better errors from map operations similar
to his suggestion.

When a map update operation (Map#{...}) or a BIF that expects a map
is given a non-map term, the exception will be:

  {badmap,Term}

This kind of exception is similar to the {badfun,Term} exception
from operations that expect a fun.

When a map operation requires a key that is not present in a map,
the following exception will be raised:

  {badkey,Key}

José Valim suggested that the exception should be
{badkey,Key,Map}. We decided not to do that because the map
could potentially be huge and cause problems if the error
propagated through links to other processes.

For BIFs, it could be argued that the exceptions could be simply
'badmap' and 'badkey', because the bad map and bad key can be found in
the argument list for the BIF in the stack backtrace. However, for the
map update operation (Map#{...}), the bad map or bad key will not be
included in the stack backtrace, so that information must be included
in the exception reason itself. For consistency, the BIFs should raise
the same exceptions as update operation.

If more than one key is missing, it is undefined which of
keys that will be reported in the {badkey,Key} exception.

3 files changed, 128 insertions, 60 deletions

diff --git a/erts/emulator/test/map_SUITE.erl b/erts/emulator/test/map_SUITE.erl
index 72b8ad91ef..39549282c0 100644
--- a/erts/emulator/test/map_SUITE.erl
+++ b/erts/emulator/test/map_SUITE.erl
@@ -79,7 +79,8 @@
 
 	%% instruction-level tests
 	t_has_map_fields/1,
-	y_regs/1
+	y_regs/1,
+	badmap_17/1
     ]).
 
 -include_lib("stdlib/include/ms_transform.hrl").
@@ -140,7 +141,8 @@ all() -> [
 
 	%% instruction-level tests
 	t_has_map_fields,
-	y_regs
+	y_regs,
+	badmap_17
     ].
 
 groups() -> [].
@@ -676,9 +678,10 @@ t_map_size(Config) when is_list(Config) ->
     N  = map_size(maps:from_list([{float(I),I}||I<-Is])),
 
     %% Error cases.
-    {'EXIT',{badarg,_}} = (catch map_size([])),
-    {'EXIT',{badarg,_}} = (catch map_size(<<1,2,3>>)),
-    {'EXIT',{badarg,_}} = (catch map_size(1)),
+    do_badmap(fun(T) ->
+                    {'EXIT',{{badmap,T},_}} =
+                      (catch map_size(T))
+              end),
     ok.
 
 build_and_check_size([K|Ks],N,M0) ->
@@ -878,9 +881,11 @@ t_update_map_expressions(Config) when is_list(Config) ->
     #{ "aa" := {$a,$a}, "ac":=41, "dc":=42 } =
         (maps:from_list([{[K1,K2],{K1,K2}}|| K1 <- Ks, K2 <- Ks]))#{ "ac" := 41, "dc" => 42 },
 
-    %% Error cases, FIXME: should be 'badmap'?
-    {'EXIT',{badarg,_}} = (catch (id(<<>>))#{ a := 42, b => 2 }),
-    {'EXIT',{badarg,_}} = (catch (id([]))#{ a := 42, b => 2 }),
+    %% Error cases.
+    do_badmap(fun(T) ->
+		      {'EXIT',{{badmap,T},_}} =
+			  (catch (T)#{a:=42,b=>2})
+	      end),
     ok.
 
 t_update_assoc(Config) when is_list(Config) ->
@@ -895,8 +900,10 @@ t_update_assoc(Config) when is_list(Config) ->
     M2 = M0#{3.0:=wrong,3.0=>new},
 
     %% Errors cases.
-    BadMap = id(badmap),
-    {'EXIT',{badarg,_}} = (catch BadMap#{nonexisting=>val}),
+    do_badmap(fun(T) ->
+		      {'EXIT',{{badmap,T},_}} =
+			  (catch T#{nonexisting=>val})
+	      end),
     ok.
 
 
@@ -963,9 +970,6 @@ t_update_assoc_large(Config) when is_list(Config) ->
     #{10:=a0,20:=b0,13.0:=new,"40":="d0",<<"50">>:="e0"} = M2,
     M2 = M0#{13.0:=wrong,13.0=>new},
 
-    %% Errors cases.
-    BadMap = id(badmap),
-    {'EXIT',{badarg,_}} = (catch BadMap#{nonexisting=>M0}),
     ok.
 
 t_update_exact(Config) when is_list(Config) ->
@@ -987,12 +991,17 @@ t_update_exact(Config) when is_list(Config) ->
 	1 := update2, 1.0 := new_val2, 1.0 => new_val3,
 	1.0 => new_val4 },
 
-
     %% Errors cases.
-    {'EXIT',{badarg,_}} = (catch M0#{nonexisting:=val}),
-    {'EXIT',{badarg,_}} = (catch M0#{1.0:=v,1.0=>v2}),
-    {'EXIT',{badarg,_}} = (catch M0#{42.0:=v,42:=v2}),
-    {'EXIT',{badarg,_}} = (catch M0#{42=>v1,42.0:=v2,42:=v3}),
+    do_badmap(fun(T) ->
+		      {'EXIT',{{badmap,T},_}} =
+			  (catch T#{nonexisting=>val})
+	      end),
+    Empty = id(#{}),
+    {'EXIT',{{badkey,nonexisting},_}} = (catch Empty#{nonexisting:=val}),
+    {'EXIT',{{badkey,nonexisting},_}} = (catch M0#{nonexisting:=val}),
+    {'EXIT',{{badkey,1.0},_}} = (catch M0#{1.0:=v,1.0=>v2}),
+    {'EXIT',{{badkey,42},_}} = (catch M0#{42.0:=v,42:=v2}),
+    {'EXIT',{{badkey,42.0},_}} = (catch M0#{42=>v1,42.0:=v2,42:=v3}),
 
     ok.
 
@@ -1071,10 +1080,10 @@ t_update_exact_large(Config) when is_list(Config) ->
     M2 = M0#{13.0=>wrong,13.0:=new},
 
     %% Errors cases.
-    {'EXIT',{badarg,_}} = (catch M0#{nonexisting:=val}),
-    {'EXIT',{badarg,_}} = (catch M0#{1.0:=v,1.0=>v2}),
-    {'EXIT',{badarg,_}} = (catch M0#{42.0:=v,42:=v2}),
-    {'EXIT',{badarg,_}} = (catch M0#{42=>v1,42.0:=v2,42:=v3}),
+    {'EXIT',{{badkey,nonexisting},_}} = (catch M0#{nonexisting:=val}),
+    {'EXIT',{{badkey,1.0},_}} = (catch M0#{1.0:=v,1.0=>v2}),
+    {'EXIT',{{badkey,42},_}} = (catch M0#{42.0:=v,42:=v2}),
+    {'EXIT',{{badkey,42.0},_}} = (catch M0#{42=>v1,42.0:=v2,42:=v3}),
 
     ok.
 
@@ -1766,12 +1775,17 @@ t_bif_map_get(Config) when is_list(Config) ->
     "tuple hi" = maps:get({1,1.0}, M1),
     "v3" = maps:get(<<"k2">>, M1),
 
-    %% error case
-    {'EXIT',{badarg, [{maps,get,_,_}|_]}} = (catch maps:get(a,[])),
-    {'EXIT',{badarg, [{maps,get,_,_}|_]}} = (catch maps:get(a,<<>>)),
-    {'EXIT',{bad_key,[{maps,get,_,_}|_]}} = (catch maps:get({1,1}, #{{1,1.0} => "tuple"})),
-    {'EXIT',{bad_key,[{maps,get,_,_}|_]}} = (catch maps:get(a,#{})),
-    {'EXIT',{bad_key,[{maps,get,_,_}|_]}} = (catch maps:get(a,#{b=>1, c=>2})),
+    %% error cases
+    do_badmap(fun(T) ->
+		      {'EXIT',{{badmap,T},[{maps,get,_,_}|_]}} =
+			  (catch maps:get(a, T))
+	      end),
+
+    {'EXIT',{{badkey,{1,1}},[{maps,get,_,_}|_]}} =
+	(catch maps:get({1,1}, #{{1,1.0} => "tuple"})),
+    {'EXIT',{{badkey,a},[{maps,get,_,_}|_]}} = (catch maps:get(a, #{})),
+    {'EXIT',{{badkey,a},[{maps,get,_,_}|_]}} =
+	(catch maps:get(a, #{b=>1, c=>2})),
     ok.
 
 t_bif_map_find(Config) when is_list(Config) ->
@@ -1804,8 +1818,10 @@ t_bif_map_find(Config) when is_list(Config) ->
     error = maps:find(1, #{ 1.0  => "float"}),
     error = maps:find({1.0,1}, #{ a=>a, {1,1.0} => "tuple hi"}), % reverse types in tuple key
 
-    {'EXIT',{badarg,[{maps,find,_,_}|_]}} = (catch maps:find(a,id([]))),
-    {'EXIT',{badarg,[{maps,find,_,_}|_]}} = (catch maps:find(a,id(<<>>))),
+    do_badmap(fun(T) ->
+		      {'EXIT',{{badmap,T},[{maps,find,_,_}|_]}} =
+			  (catch maps:find(a, T))
+	      end),
     ok.
 
 
@@ -1830,8 +1846,10 @@ t_bif_map_is_key(Config) when is_list(Config) ->
     false = maps:is_key(1.0, maps:put(1, "number", M1)),
 
     %% error case
-    {'EXIT',{badarg,[{maps,is_key,_,_}|_]}} = (catch maps:is_key(a,id([]))),
-    {'EXIT',{badarg,[{maps,is_key,_,_}|_]}} = (catch maps:is_key(a,id(<<>>))),
+    do_badmap(fun(T) ->
+		      {'EXIT',{{badmap,T},[{maps,is_key,_,_}|_]}} =
+			  (catch maps:is_key(a, T))
+	      end),
     ok.
 
 t_bif_map_keys(Config) when is_list(Config) ->
@@ -1845,11 +1863,10 @@ t_bif_map_keys(Config) when is_list(Config) ->
     [4,int,"hi",<<"key">>] = lists:sort(maps:keys(M1)),
 
     %% error case
-    {'EXIT',{badarg,[{maps,keys,_,_}|_]}} = (catch maps:keys(1 bsl 65 + 3)),
-    {'EXIT',{badarg,[{maps,keys,_,_}|_]}} = (catch maps:keys(154)),
-    {'EXIT',{badarg,[{maps,keys,_,_}|_]}} = (catch maps:keys(atom)),
-    {'EXIT',{badarg,[{maps,keys,_,_}|_]}} = (catch maps:keys([])),
-    {'EXIT',{badarg,[{maps,keys,_,_}|_]}} = (catch maps:keys(<<>>)),
+    do_badmap(fun(T) ->
+		      {'EXIT',{{badmap,T},[{maps,keys,_,_}|_]}} =
+			  (catch maps:keys(T))
+	      end),
     ok.
 
 t_bif_map_new(Config) when is_list(Config) ->
@@ -1921,9 +1938,14 @@ t_bif_map_merge(Config) when is_list(Config) ->
     ok = check_keys_exist(Ks1 ++ Ks2, M11),
 
     %% error case
-    {'EXIT',{badarg,[{maps,merge,_,_}|_]}} = (catch maps:merge((1 bsl 65 + 3), <<>>)),
-    {'EXIT',{badarg,[{maps,merge,_,_}|_]}} = (catch maps:merge(<<>>, id(#{ a => 1}))),
-    {'EXIT',{badarg,[{maps,merge,_,_}|_]}} = (catch maps:merge(id(#{ a => 2}), <<>> )),
+    do_badmap(fun(T) ->
+		      {'EXIT',{{badmap,T},[{maps,merge,_,_}|_]}} =
+			  (catch maps:merge(#{}, T)),
+		      {'EXIT',{{badmap,T},[{maps,merge,_,_}|_]}} =
+			  (catch maps:merge(T, #{})),
+		      {'EXIT',{{badmap,T},[{maps,merge,_,_}|_]}} =
+			  (catch maps:merge(T, T))
+	      end),
     ok.
 
 
@@ -1962,11 +1984,10 @@ t_bif_map_put(Config) when is_list(Config) ->
     true = is_members([number,wat,3,"hello",<<"other value">>],maps:values(M6)),
 
     %% error case
-    {'EXIT',{badarg,[{maps,put,_,_}|_]}} = (catch maps:put(1,a,1 bsl 65 + 3)),
-    {'EXIT',{badarg,[{maps,put,_,_}|_]}} = (catch maps:put(1,a,154)),
-    {'EXIT',{badarg,[{maps,put,_,_}|_]}} = (catch maps:put(1,a,atom)),
-    {'EXIT',{badarg,[{maps,put,_,_}|_]}} = (catch maps:put(1,a,[])),
-    {'EXIT',{badarg,[{maps,put,_,_}|_]}} = (catch maps:put(1,a,<<>>)),
+    do_badmap(fun(T) ->
+		      {'EXIT',{{badmap,T},[{maps,put,_,_}|_]}} =
+			  (catch maps:put(1, a, T))
+	      end),
     ok.
 
 is_members(Ks,Ls) when length(Ks) =/= length(Ls) -> false;
@@ -2009,11 +2030,10 @@ t_bif_map_remove(Config) when is_list(Config) ->
     #{ "hi" := "hello", int := 3, 4 := number} = maps:remove(18446744073709551629,maps:remove(<<"key">>,M0)),
 
     %% error case
-    {'EXIT',{badarg,[{maps,remove,_,_}|_]}} = (catch maps:remove(a,1 bsl 65 + 3)),
-    {'EXIT',{badarg,[{maps,remove,_,_}|_]}} = (catch maps:remove(1,154)),
-    {'EXIT',{badarg,[{maps,remove,_,_}|_]}} = (catch maps:remove(a,atom)),
-    {'EXIT',{badarg,[{maps,remove,_,_}|_]}} = (catch maps:remove(1,[])),
-    {'EXIT',{badarg,[{maps,remove,_,_}|_]}} = (catch maps:remove(a,<<>>)),
+    do_badmap(fun(T) ->
+		      {'EXIT',{{badmap,T},[{maps,remove,_,_}|_]}} =
+	(catch maps:remove(a, T))
+	      end),
      ok.
 
 t_bif_map_update(Config) when is_list(Config) ->
@@ -2036,10 +2056,10 @@ t_bif_map_update(Config) when is_list(Config) ->
 	4 := number, 18446744073709551629 := wazzup} = maps:update(18446744073709551629, wazzup, M0),
 
     %% error case
-    {'EXIT',{badarg,[{maps,update,_,_}|_]}} = (catch maps:update(1,none,{})),
-    {'EXIT',{badarg,[{maps,update,_,_}|_]}} = (catch maps:update(1,none,<<"value">>)),
-    {'EXIT',{badarg,[{maps,update,_,_}|_]}} = (catch maps:update(5,none,M0)),
-
+    do_badmap(fun(T) ->
+		      {'EXIT',{{badmap,T},[{maps,update,_,_}|_]}} =
+			  (catch maps:update(1, none, T))
+	      end),
     ok.
 
 
@@ -2066,10 +2086,10 @@ t_bif_map_values(Config) when is_list(Config) ->
     true = is_members([number,3,"hello2",<<"value2">>]++Vs,maps:values(M5)),
 
     %% error case
-    {'EXIT',{badarg,[{maps,values,_,_}|_]}} = (catch maps:values(1 bsl 65 + 3)),
-    {'EXIT',{badarg,[{maps,values,_,_}|_]}} = (catch maps:values(atom)),
-    {'EXIT',{badarg,[{maps,values,_,_}|_]}} = (catch maps:values([])),
-    {'EXIT',{badarg,[{maps,values,_,_}|_]}} = (catch maps:values(<<>>)),
+    do_badmap(fun(T) ->
+		      {'EXIT',{{badmap,T},[{maps,values,_,_}|_]}} =
+			  (catch maps:values(T))
+	      end),
     ok.
 
 t_erlang_hash(Config) when is_list(Config) ->
@@ -2268,8 +2288,10 @@ t_bif_map_to_list(Config) when is_list(Config) ->
 				  <<"hi">>=>v6,3=>v7,"hi"=>v8,hi=>v9,{hi,3}=>v10})),
 
     %% error cases
-    {'EXIT', {badarg,_}} = (catch maps:to_list(id(a))),
-    {'EXIT', {badarg,_}} = (catch maps:to_list(id(42))),
+    do_badmap(fun(T) ->
+		      {'EXIT', {{badmap,T},_}} =
+			  (catch maps:to_list(T))
+	      end),
     ok.
 
 
@@ -2811,6 +2833,26 @@ y_regs_update(Map0, Val0) ->
     _ = id({K1,K2,Val0,Val1}),			%Force use of Y registers.
     Map2.
 
+do_badmap(Test) ->
+    Terms = [Test,fun erlang:abs/1,make_ref(),self(),0.0/id(-1),
+	     <<0:1024>>,<<1:1>>,<<>>,<<1,2,3>>,
+	     [],{a,b,c},[a,b],atom,10.0,42,(1 bsl 65) + 3],
+    [Test(T) || T <- Terms].
+
+%% Test that a module compiled with the OTP 17 compiler will
+%% generate the correct 'badmap' exception.
+badmap_17(Config) ->
+    case ?MODULE of
+	map_SUITE -> do_badmap_17(Config);
+	_ -> {skip,"Run in map_SUITE"}
+    end.
+
+do_badmap_17(Config) ->
+    Mod = badmap_17,
+    DataDir = test_server:lookup_config(data_dir, Config),
+    Beam = filename:join(DataDir, Mod),
+    {module,Mod} = code:load_abs(Beam),
+    do_badmap(fun Mod:update/1).
 
 %% Use this function to avoid compile-time evaluation of an expression.
 id(I) -> I.
diff --git a/erts/emulator/test/map_SUITE_data/badmap_17.beam b/erts/emulator/test/map_SUITE_data/badmap_17.beam
new file mode 100644
index 0000000000..277fc34b94
--- /dev/null
+++ b/erts/emulator/test/map_SUITE_data/badmap_17.beam
diff --git a/erts/emulator/test/map_SUITE_data/badmap_17.erl b/erts/emulator/test/map_SUITE_data/badmap_17.erl
new file mode 100644
index 0000000000..0ec65e0e33
--- /dev/null
+++ b/erts/emulator/test/map_SUITE_data/badmap_17.erl
@@ -0,0 +1,26 @@
+-module(badmap_17).
+-export([update/1]).
+
+%% Compile this source file with OTP 17.
+
+update(Map) ->
+    try
+	update_1(Map),
+	error(update_did_not_fail)
+    catch
+	error:{badmap,Map} ->
+	    ok
+    end,
+    try
+	update_2(Map),
+	error(update_did_not_fail)
+    catch
+	error:{badmap,Map} ->
+	    ok
+    end.
+
+update_1(M) ->
+    M#{a=>42}.
+
+update_2(M) ->
+    M#{a:=42}.