BUG: Recognize chained fsspec URLs

[snitish]

• closes BUG: Chained urls (allowed by fsspec) not recognized by is_fsspec_url #48978
• Tests added and passed if fixing a bug or adding a new feature
• All code checks passed.
• Added type annotations to new arguments/methods/functions.
• Added an entry in the latest doc/source/whatsnew/v3.0.0.rst file if fixing a bug or adding a new feature.

The new (::[A-Za-z0-9+\-+.]+)* part of the regex will allow for optional ::<alphanumeric+-.>-like strings before the :// section of the URL, which will enable it to recognize chained fsspec URLs.

[mroeschke]

Just confirming that there isn't a solution alluded to in #48978 (comment) where fsspec provides an API already to validate fsspec URLs?

[snitish]

Just confirming that there isn't a solution alluded to in #48978 (comment) where fsspec provides an API already to validate fsspec URLs?

I checked the latest fsspec API reference and couldn't find any public functions for validating URLs.
https://filesystem-spec.readthedocs.io/en/latest/api.html

[mroeschke]

Thanks @snitish

[JMBurley]

Thanks @snitish!

I thought the bug was going to get closed the same week as when I documented the root cause and the bullet point solution. Took a few years in the end!

[ligon]

Wow, I filed this bug in October 2022. I am super pleased to have it fixed. It would be churlish to complain about the amount of time it's taken--instead, I am just impressed by how inexorable progress seems to be!

[snitish]

Thanks @JMBurley for the outline you provided - it helped me fix this bug in no time.
@ligon glad I could be of help :)