Fix TreeMaker Protocol, removing almost all # type: ignore

jaraco/path.py

@@ -2,6 +2,8 @@
 Tools for working with files and file systems
 """
 
+from __future__ import annotations
+
 import os
 import re
 import itertools
@@ -16,9 +18,10 @@
 import ctypes
 import importlib
 import pathlib
-from typing import Dict, Protocol, Union
-from typing import runtime_checkable
+from typing import TYPE_CHECKING, Dict, Protocol, Union, runtime_checkable
 
+if TYPE_CHECKING:
+    from typing_extensions import Self
 
 log = logging.getLogger(__name__)
 
@@ -290,24 +293,20 @@ class Symlink(str):
 
 @runtime_checkable
 class TreeMaker(Protocol):
-    def __truediv__(self, *args, **kwargs): ...  # pragma: no cover
-
-    def mkdir(self, **kwargs): ...  # pragma: no cover
-
-    def write_text(self, content, **kwargs): ...  # pragma: no cover
-
-    def write_bytes(self, content): ...  # pragma: no cover
-
-    def symlink_to(self, target): ...  # pragma: no cover
+    def __truediv__(self, other, /) -> Self: ...
+    def mkdir(self, *, exist_ok) -> object: ...
+    def write_text(self, content, /, *, encoding) -> object: ...
+    def write_bytes(self, content, /) -> object: ...
+    def symlink_to(self, target, /) -> object: ...
 
 
-def _ensure_tree_maker(obj: Union[str, TreeMaker]) -> TreeMaker:
-    return obj if isinstance(obj, TreeMaker) else pathlib.Path(obj)  # type: ignore[return-value]
+def _ensure_tree_maker(obj: str | TreeMaker) -> TreeMaker:
+    return obj if isinstance(obj, TreeMaker) else pathlib.Path(obj)
 
 
 def build(
     spec: FilesSpec,
-    prefix: Union[str, TreeMaker] = pathlib.Path(),  # type: ignore[assignment]
+    prefix: str | TreeMaker = pathlib.Path(),
 ):
     """
     Build a set of files/directories, as described by the spec.
@@ -339,23 +338,24 @@ def build(
 
 
 @functools.singledispatch
-def create(content: Union[str, bytes, FilesSpec], path):
+def create(content: str | bytes | FilesSpec, path: TreeMaker) -> None:
     path.mkdir(exist_ok=True)
-    build(content, prefix=path)  # type: ignore[arg-type]
+    # Mypy only looks at the signature of the main singledispatch method. So it must contain the complete Union
+    build(content, prefix=path)  # type: ignore[arg-type] # python/mypy#11727
 
 
 @create.register
-def _(content: bytes, path):
+def _(content: bytes, path: TreeMaker) -> None:
     path.write_bytes(content)
 
 
 @create.register
-def _(content: str, path):
+def _(content: str, path: TreeMaker) -> None:
     path.write_text(content, encoding='utf-8')
 
 
 @create.register
-def _(content: Symlink, path):
+def _(content: Symlink, path: TreeMaker) -> None:
     path.symlink_to(content)
 
 

tests/test_path.py

@@ -1,4 +1,5 @@
 import os
+import pathlib
 import platform
 
 import pytest
@@ -43,3 +44,12 @@ def test_is_hidden_Darwin():
     target = os.path.expanduser('~/Library')
     assert path.is_hidden(target)
     assert path.is_hidden_Darwin(target)
+
+
+def test_TreeMaker_Protocol() -> None:
+    # Ensure the validity of the TreeMaker Protocol both statically and at runtime
+    tree_maker: path.TreeMaker
+    tree_maker = pathlib.Path()
+    assert isinstance(tree_maker, path.TreeMaker)
+    tree_maker = path.Recording()
+    assert isinstance(tree_maker, path.TreeMaker)