Merge pull request #296 from python/refactor/compat-package

Refactor compatibility module

importlib_resources/_common.py

@@ -12,7 +12,7 @@
 from typing import Union, Optional, cast
 from .abc import ResourceReader, Traversable
 
-from ._compat import wrap_spec
+from .future.adapters import wrap_spec
 
 Package = Union[types.ModuleType, str]
 Anchor = Package

importlib_resources/abc.py

@@ -3,8 +3,9 @@
 import itertools
 import pathlib
 from typing import Any, BinaryIO, Iterable, Iterator, NoReturn, Text, Optional
+from typing import runtime_checkable, Protocol
 
-from ._compat import runtime_checkable, Protocol, StrPath
+from .compat.py38 import StrPath
 
 
 __all__ = ["ResourceReader", "Traversable", "TraversableResources"]

importlib_resources/compat/py38.py

@@ -0,0 +1,11 @@
+import os
+import sys
+
+from typing import Union
+
+
+if sys.version_info >= (3, 9):
+    StrPath = Union[str, os.PathLike[str]]
+else:
+    # PathLike is only subscriptable at runtime in 3.9+
+    StrPath = Union[str, "os.PathLike[str]"]

importlib_resources/compat/py39.py

@@ -0,0 +1,10 @@
+import sys
+
+
+__all__ = ['ZipPath']
+
+
+if sys.version_info >= (3, 10):
+    from zipfile import Path as ZipPath  # type: ignore
+else:
+    from zipp import Path as ZipPath  # type: ignore

importlib_resources/future/adapters.py

@@ -0,0 +1,46 @@
+import pathlib
+from contextlib import suppress
+from types import SimpleNamespace
+
+from .. import readers, _adapters
+
+
+class TraversableResourcesLoader(_adapters.TraversableResourcesLoader):
+    """
+    Adapt loaders to provide TraversableResources and other
+    compatibility.
+
+    Ensures the readers from importlib_resources are preferred
+    over stdlib readers.
+    """
+
+    def get_resource_reader(self, name):
+        return self._standard_reader() or super().get_resource_reader(name)
+
+    def _standard_reader(self):
+        return self._zip_reader() or self._namespace_reader() or self._file_reader()
+
+    def _zip_reader(self):
+        with suppress(AttributeError):
+            return readers.ZipReader(self.spec.loader, self.spec.name)
+
+    def _namespace_reader(self):
+        with suppress(AttributeError, ValueError):
+            return readers.NamespaceReader(self.spec.submodule_search_locations)
+
+    def _file_reader(self):
+        try:
+            path = pathlib.Path(self.spec.origin)
+        except TypeError:
+            return None
+        if path.exists():
+            return readers.FileReader(SimpleNamespace(path=path))
+
+
+def wrap_spec(package):
+    """
+    Override _adapters.wrap_spec to use TraversableResourcesLoader
+    from above. Ensures that future behavior is always available on older
+    Pythons.
+    """
+    return _adapters.SpecLoaderAdapter(package.__spec__, TraversableResourcesLoader)

importlib_resources/readers.py

@@ -9,7 +9,7 @@
 from . import abc
 
 from ._itertools import only
-from ._compat import ZipPath
+from .compat.py39 import ZipPath
 
 
 def remove_duplicates(items):