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 give it in an invalid scheme, say by extra whitespace or invalid characters:
>>> hyperlink.parse(" http://")
…
ValueError: invalid scheme: ' http'. Only alphanumeric, "+", "-", and "." allowed. Did you meant to call URL.from_text()?
>>> hyperlink.parse("h_t_t_p://")
…
ValueError: invalid scheme: 'h_t_t_p'. 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.