fix: fix type hints for delete_existing_files()

[jameslamb]

Contributes to #87

Resolves these errors from mypy:

_rapids_dependency_file_generator.py:32: error: Value of type variable "AnyStr" of "walk" cannot be "Union[PathLike[Any], Any]"  [type-var]
_rapids_dependency_file_generator.py:33: error: Need type annotation for "fn"  [var-annotated]
_rapids_dependency_file_generator.py:33: error: Argument 1 to "filter" has incompatible type "Callable[[Any], Any]"; expected "Callable[[Union[PathLike[Any], Any]], TypeGuard[Never]]"  [arg-type]
_rapids_dependency_file_generator.py:33: error: Item "PathLike[Any]" of "Union[PathLike[Any], Any]" has no attribute "endswith"  [union-attr]

os.PathLike is not intended to be used as a generic type hint wherever you might have a string that represents a filepath. It has a different, very specific purpose. From https://docs.python.org/3/library/os.html#os.PathLike

An abstract base class for objects representing a file system path, e.g. pathlib.PurePath.

delete_existing_files() is always passed a Python string, so it's type hint should be str.

dependency-file-generator/src/rapids_dependency_file_generator/_cli.py

Lines 24 to 34 in 6b0247a

	parser.add_argument(
	"--clean",
	nargs="?",
	default=None,
	const="",
	help=(
	"Delete any files previously created by dfg before running. An optional "
	"path to clean may be provided, otherwise the current working directory "
	"is used as the root from which to clean."
	),
	)

dependency-file-generator/src/rapids_dependency_file_generator/_cli.py

Lines 117 to 118 in 6b0247a

	if args.clean == "":
	args.clean = os.path.dirname(os.path.abspath(args.config))

dependency-file-generator/src/rapids_dependency_file_generator/_cli.py

Lines 148 to 149 in 6b0247a

	if args.clean:
	delete_existing_files(args.clean)

import os

p = os.path.dirname(os.path.abspath("README.md"))

type(p)
# <class 'str'>

isinstance(p, os.PathLike)
# False

How I tested this

mypy \
    --ignore-missing-imports \
    --explicit-package-bases \
    ./src

[bdice]

Maybe we can make fewer, larger PRs to cut down on the number of reviews? It seems like there are quite a few of these typing-related changes and doing them two lines at a time seems slow.

[jameslamb]

Sure, I'll start making them a bit bigger. Was trying to keep them small and focused so they'd be easier to review but I might not have found the right balance there.

After this + #94 are merged I think this typing work could be finished in just 1 or maybe 2 more PRs.

[GPUtester]

🎉 This PR is included in version 1.13.9 🎉

The release is available on:

• GitHub release
• PyPI release
• Conda release - rapidsai
• Conda release - rapidsai-nightly

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