ValueError when defining an Azure UPath with protocol "abfss"

[jslorrma]

Description

When attempting to define a UPath with the Azure protocol "abfss", a ValueError is raised:

File .../lib/python3.11/site-packages/upath/implementations/cloud.py:104, in AzurePath.__init__(self, protocol, *args, **storage_options)
    102 print(self.drive, len(self.parts))
    103 if not self.drive and len(self.parts) > 1:
--> 104     raise ValueError("non key-like path provided (bucket/container missing)")

ValueError: non key-like path provided (bucket/container missing)

Steps to Reproduce

Define a UPath with the "abfss" protocol:

from upath import UPath
from azure.identity import DefaultAzureCredential

credential = DefaultAzureCredential(exclude_managed_identity_credential=True)
UPath("abfss://<container>@<account_name>.dfs.core.windows.net/<path>/", credential=credential)

Analysis

From my debugging and analysis the root cause of this issue is that the "abfss" protocol is missing in the WrappedFileSystemFlavour.protocol_config["netloc_is_anchor"] list here. This list only includes "abfs", "az", and "adl" from the adlfs filesystem protocols. Consequently, paths like "abfs://container/path..." function as expected, but paths starting with "abfss"-protocol trigger an error. On closer look, it turns out that the absence of "abfss" in the netloc_is_anchor list causes the splitdrive method here of WrappedFileSystemFlavour to return an empty drive.

def splitdrive(self, path: PathOrStr) -> tuple[str, str]:
    if self.netloc_is_anchor:  # <-- this evaluates to False in case of "abfss" is used in UPath
    ...
    else:
        # all other cases don't have a drive
        return "", path

Question

Is the exclusion of the "abfss" protocol in the netloc_is_anchor list intentional or a mistake?