Fix module and protocol subtyping, module hasattr (#13778)

Fixes
#13771 (comment)

Author: hauntsaninja

mypy/checker.py

@@ -6472,8 +6472,14 @@ def partition_union_by_attr(
         return with_attr, without_attr
 
     def has_valid_attribute(self, typ: Type, name: str) -> bool:
-        if isinstance(get_proper_type(typ), AnyType):
+        p_typ = get_proper_type(typ)
+        if isinstance(p_typ, AnyType):
             return False
+        if isinstance(p_typ, Instance) and p_typ.extra_attrs and p_typ.extra_attrs.mod_name:
+            # Presence of module_symbol_table means this check will skip ModuleType.__getattr__
+            module_symbol_table = p_typ.type.names
+        else:
+            module_symbol_table = None
         with self.msg.filter_errors() as watcher:
             analyze_member_access(
                 name,
@@ -6487,6 +6493,7 @@ def has_valid_attribute(self, typ: Type, name: str) -> bool:
                 chk=self,
                 # This is not a real attribute lookup so don't mess with deferring nodes.
                 no_deferral=True,
+                module_symbol_table=module_symbol_table,
             )
         return not watcher.has_new_errors()
 

mypy/subtypes.py

@@ -1082,6 +1082,7 @@ def find_member(
             and name not in ["__getattr__", "__setattr__", "__getattribute__"]
             and not is_operator
             and not class_obj
+            and itype.extra_attrs is None  # skip ModuleType.__getattr__
         ):
             for method_name in ("__getattribute__", "__getattr__"):
                 # Normally, mypy assumes that instances that define __getattr__ have all

mypy/types.py

@@ -1192,6 +1192,9 @@ def __eq__(self, other: object) -> bool:
     def copy(self) -> ExtraAttrs:
         return ExtraAttrs(self.attrs.copy(), self.immutable.copy(), self.mod_name)
 
+    def __repr__(self) -> str:
+        return f"ExtraAttrs({self.attrs!r}, {self.immutable!r}, {self.mod_name!r})"
+
 
 class Instance(ProperType):
     """An instance type of form C[T1, ..., Tn].

test-data/unit/check-isinstance.test

@@ -2895,6 +2895,13 @@ else:
     mod.y  # E: Module has no attribute "y"
     reveal_type(mod.x)  # N: Revealed type is "builtins.int"
 
+if hasattr(mod, "x"):
+    mod.y  # E: Module has no attribute "y"
+    reveal_type(mod.x)  # N: Revealed type is "builtins.int"
+else:
+    mod.y  # E: Module has no attribute "y"
+    reveal_type(mod.x)  # N: Revealed type is "builtins.int"
+
 [file mod.py]
 x: int
 [builtins fixtures/module.pyi]

test-data/unit/check-modules.test

@@ -1672,11 +1672,11 @@ mod_any: Any = m
 mod_int: int = m  # E: Incompatible types in assignment (expression has type Module, variable has type "int")
 
 reveal_type(mod_mod)  # N: Revealed type is "types.ModuleType"
-mod_mod.a  # E: Module has no attribute "a"
+reveal_type(mod_mod.a)  # N: Revealed type is "Any"
 reveal_type(mod_mod2)  # N: Revealed type is "types.ModuleType"
-mod_mod2.a  # E: Module has no attribute "a"
+reveal_type(mod_mod2.a)  # N: Revealed type is "Any"
 reveal_type(mod_mod3)  # N: Revealed type is "types.ModuleType"
-mod_mod3.a  # E: Module has no attribute "a"
+reveal_type(mod_mod3.a)  # N: Revealed type is "Any"
 reveal_type(mod_any)  # N: Revealed type is "Any"
 
 [file m.py]
@@ -1736,7 +1736,7 @@ if bool():
 else:
     x = n
 
-x.a  # E: Module has no attribute "a"
+reveal_type(x.nope)  # N: Revealed type is "Any"
 reveal_type(x.__file__)  # N: Revealed type is "builtins.str"
 
 [file m.py]

test-data/unit/fine-grained-inspect.test

@@ -236,7 +236,7 @@ class C: ...
 [builtins fixtures/module.pyi]
 [out]
 ==
-{"<pack.bar>": ["C", "__annotations__", "__doc__", "__file__", "__name__", "__package__", "bar", "x"], "ModuleType": ["__file__"]}
+{"<pack.bar>": ["C", "__annotations__", "__doc__", "__file__", "__name__", "__package__", "bar", "x"], "ModuleType": ["__file__", "__getattr__"]}
 
 [case testInspectModuleDef]
 # inspect2: --show=definition --include-kind foo.py:2:1

test-data/unit/lib-stub/types.pyi

@@ -1,12 +1,13 @@
-from typing import TypeVar
+from typing import Any, TypeVar
 import sys
 
 _T = TypeVar('_T')
 
 def coroutine(func: _T) -> _T: pass
 
 class ModuleType:
-    __file__ = ... # type: str
+    __file__: str
+    def __getattr__(self, name: str) -> Any: pass
 
 if sys.version_info >= (3, 10):
     class Union: