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authorBjörn Gustavsson <[email protected]>2018-08-10 07:43:31 +0200
committerBjörn Gustavsson <[email protected]>2018-08-13 09:26:36 +0200
commit7e1eb2ed1f724945884d839bd8a99154e9382849 (patch)
tree42dd357548847ad0197c825157a2b091838a6099 /lib/compiler
parent77d307e6c3e705e14843101d4c5348c6c079ace0 (diff)
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Correct error behavior of is_map_key/2 in guards
Consider the following functions: foo() -> bar(not_a_map). bar(M) when not is_map_key(a, M) -> ok; bar(_) -> error. What will `foo/0` return? It depends. If the module is compiled with the default compiler options, the return value will be `ok`. If the module is compiled with the `inline` option, the return value will be `error`. The correct value is `error`, because the call to `is_map_key/2` when the second argument is not a map should fail the entire guard. That is the way other failing guards BIFs are handled. For example: foo() -> bar(not_a_tuple). bar(T) when not element(1, T) -> ok; bar(_) -> error. `foo/0` always returns `error` (whether the code is inlined or not). This bug can be fixed by changing the classification of `is_map_key/2` in the `erl_internal` module. It is now classified as a type test, which is incorrect because type tests should not fail. Reclassifying it as a plain guard BIF corrects the bug. This correction also fixes the internal consistency check failure which was reported in: https://bugs.erlang.org/browse/ERL-699
Diffstat (limited to 'lib/compiler')
-rw-r--r--lib/compiler/src/v3_codegen.erl5
-rw-r--r--lib/compiler/test/map_SUITE.erl46
2 files changed, 45 insertions, 6 deletions
diff --git a/lib/compiler/src/v3_codegen.erl b/lib/compiler/src/v3_codegen.erl
index 6cd114abf7..e9152ba88f 100644
--- a/lib/compiler/src/v3_codegen.erl
+++ b/lib/compiler/src/v3_codegen.erl
@@ -1621,11 +1621,6 @@ test_cg(is_boolean, [#k_atom{val=Val}], Fail, I, Vdb, Bef, St) ->
false -> [{jump,{f,Fail}}]
end,
{Is,Aft,St};
-test_cg(is_map_key, As, Fail, I, Vdb, Bef, St) ->
- [Key,Map] = cg_reg_args(As, Bef),
- Aft = clear_dead(Bef, I, Vdb),
- F = {f,Fail},
- {[{test,is_map,F,[Map]},{test,has_map_fields,F,Map,{list,[Key]}}],Aft,St};
test_cg(Test, As, Fail, I, Vdb, Bef, St) ->
Args = cg_reg_args(As, Bef),
Aft = clear_dead(Bef, I, Vdb),
diff --git a/lib/compiler/test/map_SUITE.erl b/lib/compiler/test/map_SUITE.erl
index 9182c1b5ed..c004dca834 100644
--- a/lib/compiler/test/map_SUITE.erl
+++ b/lib/compiler/test/map_SUITE.erl
@@ -1212,10 +1212,25 @@ t_guard_bifs(Config) when is_list(Config) ->
true = map_guard_empty_2(),
true = map_guard_head(#{a=>1}),
false = map_guard_head([]),
+
true = map_get_head(#{a=>1}),
+ false = map_get_head(#{}),
+ false = map_get_head([]),
+
+ true = map_get_head_not(#{a=>false}),
+ false = map_get_head_not(#{a=>true}),
+ false = map_get_head(#{}),
false = map_get_head([]),
+
true = map_is_key_head(#{a=>1}),
false = map_is_key_head(#{}),
+ false = map_is_key_head(not_a_map),
+
+ false = map_is_key_head_not(#{a=>1}),
+ true = map_is_key_head_not(#{b=>1}),
+ true = map_is_key_head_not(#{}),
+ false = map_is_key_head_not(not_a_map),
+
true = map_guard_body(#{a=>1}),
false = map_guard_body({}),
true = map_guard_pattern(#{a=>1, <<"hi">> => "hi" }),
@@ -1224,6 +1239,25 @@ t_guard_bifs(Config) when is_list(Config) ->
true = map_guard_ill_map_size(),
true = map_field_check_sequence(#{a=>1}),
false = map_field_check_sequence(#{}),
+
+ %% The guard BIFs used in a body.
+
+ v = map_get(a, id(#{a=>v})),
+ {'EXIT',{{badkey,a},_}} =
+ (catch map_get(a, id(#{}))),
+ {'EXIT',{{badmap,not_a_map},_}} =
+ (catch map_get(a, id(not_a_map))),
+
+ true = is_map_key(a, id(#{a=>1})),
+ false = is_map_key(b, id(#{a=>1})),
+ false = is_map_key(b, id(#{})),
+ {'EXIT',{{badmap,not_a_map},_}} =
+ (catch is_map_key(b, id(not_a_map))),
+
+ {true,v} = erl_699(#{k=>v}),
+ {'EXIT',{{badkey,k},_}} = (catch erl_699(#{})),
+ {'EXIT',{{badmap,not_a_map},_}} = (catch erl_699(not_a_map)),
+
ok.
map_guard_empty() when is_map(#{}); false -> true.
@@ -1236,8 +1270,14 @@ map_guard_head(_) -> false.
map_get_head(M) when map_get(a, M) =:= 1 -> true;
map_get_head(_) -> false.
+map_get_head_not(M) when not map_get(a, M) -> true;
+map_get_head_not(_) -> false.
+
map_is_key_head(M) when is_map_key(a, M) -> true;
-map_is_key_head(M) -> false.
+map_is_key_head(_) -> false.
+
+map_is_key_head_not(M) when not is_map_key(a, M) -> true;
+map_is_key_head_not(_) -> false.
map_guard_body(M) -> is_map(M).
@@ -1254,6 +1294,10 @@ map_field_check_sequence(M)
map_field_check_sequence(_) ->
false.
+erl_699(M) ->
+ %% Used to cause an internal consistency failure.
+ {is_map_key(k, M),maps:get(k, M)}.
+
t_guard_sequence(Config) when is_list(Config) ->
{1, "a"} = map_guard_sequence_1(#{seq=>1,val=>id("a")}),
{2, "b"} = map_guard_sequence_1(#{seq=>2,val=>id("b")}),