Fix TypedDict.get("missing_key") with string literal (#9906)

Previously this would throw an error, however according to PEP 589
.get() should be allowed for arbitrary expressions with type str, while
only [] throws an error.

Author: freundTech

mypy/plugins/default.py

@@ -237,8 +237,7 @@ def typed_dict_get_callback(ctx: MethodContext) -> Type:
         for key in keys:
             value_type = get_proper_type(ctx.type.items.get(key))
             if value_type is None:
-                ctx.api.msg.typeddict_key_not_found(ctx.type, key, ctx.context)
-                return AnyType(TypeOfAny.from_error)
+                return ctx.default_return_type
 
             if len(ctx.arg_types) == 1:
                 output_types.append(value_type)

test-data/unit/check-literal.test

@@ -2227,7 +2227,7 @@ d[c_key]                      # E: TypedDict "Outer" has no key 'c'
 
 reveal_type(d.get(a_key, u))  # N: Revealed type is 'Union[builtins.int, __main__.Unrelated]'
 reveal_type(d.get(b_key, u))  # N: Revealed type is 'Union[builtins.str, __main__.Unrelated]'
-d.get(c_key, u)               # E: TypedDict "Outer" has no key 'c'
+reveal_type(d.get(c_key, u))  # N: Revealed type is 'builtins.object'
 
 reveal_type(d.pop(a_key))     # E: Key 'a' of TypedDict "Outer" cannot be deleted \
                               # N: Revealed type is 'builtins.int'
@@ -2271,11 +2271,11 @@ reveal_type(a[int_key_good])         # N: Revealed type is 'builtins.int'
 reveal_type(b[int_key_good])         # N: Revealed type is 'builtins.int'
 reveal_type(c[str_key_good])         # N: Revealed type is 'builtins.int'
 reveal_type(c.get(str_key_good, u))  # N: Revealed type is 'Union[builtins.int, __main__.Unrelated]'
+reveal_type(c.get(str_key_bad, u))   # N: Revealed type is 'builtins.object'
 
 a[int_key_bad]                       # E: Tuple index out of range
 b[int_key_bad]                       # E: Tuple index out of range
 c[str_key_bad]                       # E: TypedDict "MyDict" has no key 'missing'
-c.get(str_key_bad, u)                # E: TypedDict "MyDict" has no key 'missing'
 [builtins fixtures/dict.pyi]
 [typing fixtures/typing-typeddict.pyi]
 [out]
@@ -2342,12 +2342,12 @@ reveal_type(test.get(good_keys, 3))               # N: Revealed type is 'Union[_
 reveal_type(test.pop(optional_keys))              # N: Revealed type is 'Union[__main__.D, __main__.E]'
 reveal_type(test.pop(optional_keys, 3))           # N: Revealed type is 'Union[__main__.D, __main__.E, Literal[3]?]'
 reveal_type(test.setdefault(good_keys, AAndB()))  # N: Revealed type is 'Union[__main__.A, __main__.B]'
+reveal_type(test.get(bad_keys))                   # N: Revealed type is 'builtins.object*'
+reveal_type(test.get(bad_keys, 3))                # N: Revealed type is 'builtins.object'
 del test[optional_keys]
 
 
 test[bad_keys]                  # E: TypedDict "Test" has no key 'bad'
-test.get(bad_keys)              # E: TypedDict "Test" has no key 'bad'
-test.get(bad_keys, 3)           # E: TypedDict "Test" has no key 'bad'
 test.pop(good_keys)             # E: Key 'a' of TypedDict "Test" cannot be deleted \
                                 # E: Key 'b' of TypedDict "Test" cannot be deleted
 test.pop(bad_keys)              # E: Key 'a' of TypedDict "Test" cannot be deleted \
@@ -2436,14 +2436,12 @@ good_keys: Literal['b', 'c']
 
 x[bad_keys]         # E: TypedDict "D1" has no key 'd' \
                     # E: TypedDict "D2" has no key 'a'
-x.get(bad_keys)     # E: TypedDict "D1" has no key 'd' \
-                    # E: TypedDict "D2" has no key 'a'
-x.get(bad_keys, 3)  # E: TypedDict "D1" has no key 'd' \
-                    # E: TypedDict "D2" has no key 'a'
 
 reveal_type(x[good_keys])           # N: Revealed type is 'Union[__main__.B, __main__.C]'
 reveal_type(x.get(good_keys))       # N: Revealed type is 'Union[__main__.B, __main__.C]'
 reveal_type(x.get(good_keys, 3))    # N: Revealed type is 'Union[__main__.B, Literal[3]?, __main__.C]'
+reveal_type(x.get(bad_keys))        # N: Revealed type is 'builtins.object*'
+reveal_type(x.get(bad_keys, 3))     # N: Revealed type is 'builtins.object'
 
 [builtins fixtures/dict.pyi]
 [typing fixtures/typing-typeddict.pyi]

test-data/unit/check-typeddict.test

@@ -969,8 +969,8 @@ d.get('x', 1, 2) # E: No overload variant of "get" of "Mapping" matches argument
                  # N: Possible overload variants: \
                  # N:     def get(self, k: str) -> object \
                  # N:     def [V] get(self, k: str, default: Union[int, V]) -> object
-x = d.get('z') # E: TypedDict "D" has no key 'z'
-reveal_type(x) # N: Revealed type is 'Any'
+x = d.get('z')
+reveal_type(x) # N: Revealed type is 'builtins.object*'
 s = ''
 y = d.get(s)
 reveal_type(y) # N: Revealed type is 'builtins.object*'
@@ -1689,8 +1689,7 @@ td: Union[TDA, TDB]
 
 reveal_type(td.get('a'))  # N: Revealed type is 'builtins.int'
 reveal_type(td.get('b'))  # N: Revealed type is 'Union[builtins.str, builtins.int]'
-reveal_type(td.get('c'))  # E: TypedDict "TDA" has no key 'c' \
-                          # N: Revealed type is 'Union[Any, builtins.int]'
+reveal_type(td.get('c'))  # N: Revealed type is 'builtins.object*'
 
 reveal_type(td['a'])  # N: Revealed type is 'builtins.int'
 reveal_type(td['b'])  # N: Revealed type is 'Union[builtins.str, builtins.int]'

test-data/unit/pythoneval.test

@@ -1074,14 +1074,14 @@ D = TypedDict('D', {'x': int, 'y': str})
 d: D
 reveal_type(d.get('x'))
 reveal_type(d.get('y'))
-d.get('z')
+reveal_type(d.get('z'))
 d.get()
 s = ''
 reveal_type(d.get(s))
 [out]
 _testTypedDictGet.py:7: note: Revealed type is 'builtins.int'
 _testTypedDictGet.py:8: note: Revealed type is 'builtins.str'
-_testTypedDictGet.py:9: error: TypedDict "D" has no key 'z'
+_testTypedDictGet.py:9: note: Revealed type is 'builtins.object*'
 _testTypedDictGet.py:10: error: All overload variants of "get" of "Mapping" require at least one argument
 _testTypedDictGet.py:10: note: Possible overload variants:
 _testTypedDictGet.py:10: note:     def get(self, key: str) -> object