Add __path__ to package __init__ (#9454)

Resolves #1422

Co-authored-by: hauntsaninja <>

Author: hauntsaninja

mypy/nodes.py

@@ -99,10 +99,11 @@ def get_column(self) -> int:
 
 
 implicit_module_attrs: Final = {
-    "__name__": "__builtins__.str",
-    "__doc__": None,  # depends on Python version, see semanal.py
-    "__file__": "__builtins__.str",
-    "__package__": "__builtins__.str",
+    '__name__': '__builtins__.str',
+    '__doc__': None,  # depends on Python version, see semanal.py
+    '__path__': None,  # depends on if the module is a package
+    '__file__': '__builtins__.str',
+    '__package__': '__builtins__.str'
 }
 
 

mypy/semanal.py

@@ -427,6 +427,17 @@ def add_implicit_module_attrs(self, file_node: MypyFile) -> None:
                 else:
                     typ = UnionType([UnboundType('__builtins__.str'),
                                      UnboundType('__builtins__.unicode')])
+            elif name == '__path__':
+                if not file_node.is_package_init_file():
+                    continue
+                # Need to construct the type ourselves, to avoid issues with __builtins__.list
+                # not being subscriptable or typing.List not getting bound
+                sym = self.lookup_qualified("__builtins__.list", Context())
+                if not sym:
+                    continue
+                node = sym.node
+                assert isinstance(node, TypeInfo)
+                typ = Instance(node, [self.str_type()])
             else:
                 assert t is not None, 'type should be specified for {}'.format(name)
                 typ = UnboundType(t)

test-data/unit/check-incomplete-fixture.test

@@ -12,14 +12,6 @@ import m
 m.x # E: "object" has no attribute "x"
 [file m.py]
 
-[case testListMissingFromStubs]
-from typing import List
-def f(x: List[int]) -> None: pass
-[out]
-main:1: error: Module "typing" has no attribute "List"
-main:1: note: Maybe your test fixture does not define "builtins.list"?
-main:1: note: Consider adding [builtins fixtures/list.pyi] to your test description
-
 [case testDictMissingFromStubs]
 from typing import Dict
 def f(x: Dict[int]) -> None: pass

test-data/unit/check-modules.test

@@ -2888,6 +2888,16 @@ from mystery import a, b as b, c as d
 tmp/stub.pyi:1: error: Cannot find implementation or library stub for module named "mystery"
 tmp/stub.pyi:1: note: See https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-imports
 
+[case testPackagePath]
+import p
+reveal_type(p.__path__)  # N: Revealed type is "builtins.list[builtins.str]"
+p.m.__path__  # E: "object" has no attribute "__path__"
+
+[file p/__init__.py]
+from . import m as m
+[file p/m.py]
+[builtins fixtures/list.pyi]
+
 [case testReExportAllInStub]
 from m1 import C
 from m1 import D  # E: Module "m1" has no attribute "D"
@@ -3121,4 +3131,4 @@ main:2: error: Cannot find implementation or library stub for module named "blea
 # flags: --ignore-missing-imports
 import bleach.xyz
 from bleach.abc import fgh
-[file bleach/__init__.pyi]
+[file bleach/__init__.pyi]

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

@@ -1437,7 +1437,7 @@ x = 1
 [file b/foo.py]
 [file b/__init__.py.2]
 # Dummy change
-[builtins fixtures/bool.pyi]
+[builtins fixtures/primitives.pyi]
 [out]
 ==
 

test-data/unit/fixtures/args.pyi

@@ -1,6 +1,6 @@
 # Builtins stub used to support *args, **kwargs.
 
-from typing import TypeVar, Generic, Iterable, Tuple, Dict, Any, overload, Mapping
+from typing import TypeVar, Generic, Iterable, Sequence, Tuple, Dict, Any, overload, Mapping
 
 Tco = TypeVar('Tco', covariant=True)
 T = TypeVar('T')
@@ -22,6 +22,8 @@ class tuple(Iterable[Tco], Generic[Tco]): pass
 
 class dict(Iterable[T], Mapping[T, S], Generic[T, S]): pass
 
+class list(Generic[T], Sequence[T]): pass
+
 class int:
     def __eq__(self, o: object) -> bool: pass
 class str: pass

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

@@ -20,4 +20,8 @@ class bytes: pass
 class function: pass
 class ellipsis: pass
 
+from typing import Generic, Sequence, TypeVar
+_T = TypeVar('_T')
+class list(Generic[_T], Sequence[_T]): pass
+
 # Definition of None is implicit