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author | Björn Gustavsson <[email protected]> | 2018-08-10 07:43:31 +0200 |
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committer | Björn Gustavsson <[email protected]> | 2018-08-13 09:26:36 +0200 |
commit | 7e1eb2ed1f724945884d839bd8a99154e9382849 (patch) | |
tree | 42dd357548847ad0197c825157a2b091838a6099 /lib/compiler | |
parent | 77d307e6c3e705e14843101d4c5348c6c079ace0 (diff) | |
download | otp-7e1eb2ed1f724945884d839bd8a99154e9382849.tar.gz otp-7e1eb2ed1f724945884d839bd8a99154e9382849.tar.bz2 otp-7e1eb2ed1f724945884d839bd8a99154e9382849.zip |
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.erl | 5 | ||||
-rw-r--r-- | lib/compiler/test/map_SUITE.erl | 46 |
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")}), |