fs.ls("/") raises error after fs.rm("/", recursive=True) for memory filesystem

[benlindsay]

To replicate this error, run this:

import fsspec

fs = fsspec.filesystem("memory")
fs.rm("/", recursive=True)
fs.ls("/")

Which results in the following traceback:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/.../site-packages/fsspec/implementations/memory.py", line 91, in ls
    raise FileNotFoundError(path)
FileNotFoundError

I would expect it to return an empty list as it does before the ls.rm() call.

[martindurant]

Good point, there is an implicit root directory in pseudo_dirs that the rm will have deleted, but we should enforce that it is always present.

[martindurant]

Since you cannot delete "/" (or ""), should it raise to attempt to do so, or silently ignore removing the root?

[benlindsay]

I'm leaning towards silently ignoring removing the root, but open to whatever makes the most sense. My thought is that in a real filesystem, if you do rm -rf /, I would theoretically expect the root directory to still be there after that's all done, although I don't intend to actually try it 😅. Also, if we think about how this would apply in a DirFileSystem context, if, say, we have a DirFileSystem representing an S3 bucket, I think the DirFileSystem shouldn't be able to reach outside of that directory, so removing "/" should just remove the contents of the bucket, not the bucket itself. Thoughts?