ARROW-8213: [Python][Dataset] Opening a dataset with a local incorrect path gives confusing error message

[kszucs]

Workaround until it is properly handled in the C++ implementation.

[github-actions]

https://issues.apache.org/jira/browse/ARROW-8213

[pitrou]

Well, can you try to fix it in the C++ implementation? :-) Or do you want me to do it?

[jorisvandenbossche]

Well, can you try to fix it in the C++ implementation? :-) Or do you want me to do it?

I thought you didn't want to deal with non-URIs on the C++ FileSystem level?

[pitrou]

There's a C++ function called FileSystemFromUriOrPath. I don't remember why the Python side doesn't use it.

[pitrou]

@jorisvandenbossche Opinions on this?

[jorisvandenbossche]

Thanks for that fix! Yeah, I think catching "empty scheme" in the error message is the most straightforward way to handle it

[kszucs]

I don't like this kind of error handling because it is error prone, bound to an error message instead of an error type or kind - I'm fine with it as a workaround though.

[wesm]

+1, this seems okay to me, we can iterate/improve this logic surely