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What errors can you get from hyperlink.parse?

Mostly you get hyperlink.URLParseError, but you can occasionally get a ValueError as well.

I write a lot of code that uses hyperlink.parse. I want to make sure my code can handle all the exceptions which are thrown by hyperlink, and react accordingly.

The hyperlink URL parser is fairly robust, and handles quite a few strings that don’t look like URLs to me, for example:

>>> import hyperlink
>>> hyperlink.parse("")
DecodedURL(url=URL.from_text(''))

It throws a URLParseError for most invalid URLs:

>>> hyperlink.parse("http://http://")
…
hyperlink._url.URLParseError: port must not be empty: 'http:'

It throws a ValueError in a handful of cases, if you include whitespace in the scheme:

>>> hyperlink.parse(" http://")
…
ValueError: invalid scheme: ' http'. Only alphanumeric, "+", "-", and "." allowed. Did you meant to call URL.from_text()?

It throws a TypeError if you pass a value that isn’t a str:

>>> hyperlink.parse(b"")
…
TypeError: expected str for text, got b''

All of my new code is type checked, so it’s unlikely I’d encounter this in practice.

Given that URLParseError is a subclass of ValueError, it would be sensible to wrap calls to hyperlink.parse with try … except ValueError. Based on a cursory read of the hyperlink source code, I can’t see any places where it could throw a different exception type.