Inconsistent listdir() and rmdir() method signature across class hierarchy

[DimitriPapadopoulos]

Problem description

The listdir() and rmdir() signatures are inconsistent across this class hierarchy:

BaseStore                             zarr/_storage/store.py
└── Store                             zarr/_storage/store.py
    ├── ABSStore                      zarr/_storage/absstore.py
    ├── MemoryStore                   zarr/storage.py
    ├── DirectoryStore                zarr/storage.py
    ├── FSStore                       zarr/storage.py
    ├── ZipStore                      zarr/storage.py
    ├── LRUStoreCache                 zarr/storage.py
    ├── SQLiteStore                   zarr/storage.py
    └── ConsolidatedMetadataStore     zarr/storage.py

class Store(BaseStore):
    [...]
    def listdir(self, path: str = "") -> List[str]:
    [...]
    def rmdir(self, path: str = "") -> None:
    [...]

class ABSStore(Store):
    [...]
    def listdir(self, path=None):
    [...]
    def rmdir(self, path=None):
    [...]

class MemoryStore(Store):
    [...]
    def listdir(self, path: Path = None) -> List[str]:
    [...]
    def rmdir(self, path: Path = None):
    [...]

class DirectoryStore(Store):
    [...]
    def listdir(self, path=None):
    [...]
    def rmdir(self, path=None):
    [...]

class FSStore(Store):
    [...]
    def listdir(self, path=None):
    [...]
    def rmdir(self, path=None):
    [...]

class ZipStore(Store):
    [...]
    def listdir(self, path=None):
    [...]

class LRUStoreCache(Store):
    [...]
    def listdir(self, path: Path = None):
    [...]

class SQLiteStore(Store):
    [...]
    def listdir(self, path=None):
    [...]
    def rmdir(self, path=None):
    [...]

class ConsolidatedMetadataStore(Store):
    [...]
    def listdir(self, path):
    [...]

• Argument path should consistently be either a str or a Path
• The default value of path should consistently be either "" or None.
• ConsolidatedMetadataStore.listdir() needs a default value.

[DimitriPapadopoulos]

One problem is that BaseStore/Store are defined in zarr/_storage/store.py, where Path has not been defined so far, while most subclasses are defined in zarr/storage.py, which defines:

zarr-python/zarr/storage.py

Line 86 in f0677c2

Path = Union[str, bytes, None]

[DimitriPapadopoulos]

But then why bytes? All paths should be str, shouldn't they?

[joshmoore]

@jakirkham: did you ever get a chance to look at this one?

[DimitriPapadopoulos]

Can Path be replaced by pathlib.Path? If not, re-using a well-known class name is confusing. Otherwise, switching should not be a problem for Python >= 3.8.