bpo-42967: coerce bytes separator to string in urllib.parse_qs(l)

[Fidget-Spinner]

urllib.parse_qsl previously (and currently) deals with bytes query string by coercing them to string internally. After bpo-42967 was fixed, a new separator argument was added. This patch follows the rest of parse_qsl by coercing the separator to string too.

https://bugs.python.org/issue42967

[Fidget-Spinner]

Off topic: wow the bot is more alert than I thought. I never knew mentioning a bpo in the description would also cause it to link

[encukou]

Would it make sense to disallow mixing types (e.g. string qs with bytes separator)?
qs, separator, _coerce_result = _coerce_args(qs, separator) should do that.

[Fidget-Spinner]

Would it make sense to disallow mixing types (e.g. string qs with bytes separator)?
qs, separator, _coerce_result = _coerce_args(qs, separator) should do that.

Yeap I thought about that for a while :). The problem is it will break existing code:

# currently this works
urllib.parse_qsl(b"qwerty")

# but after patch:
urllib.parse_qsl(b"qwerty")
# TypeError: Cannot mix str and non-str arguments

Because the default separator argument is a string "&", passing in bytes will make _coerce_args complain about mixing types.

[orsenthil]

@Fidget-Spinner - This change looks good to me.

Ouch! - We missed this in the original PR. Using the same ticket or a new ticket is fine with with me.

[Fidget-Spinner]

@Fidget-Spinner - This change looks good to me.

Ouch! - We missed this in the original PR. Using the same ticket or a new ticket is fine with with me.

Good thing this isn't a regression against prior versions (IMO, I may be wrong here). Because currently, the following still works, and all existing user code should look like this:

urllib.parse_qsl("qwerty")
urllib.parse_qsl(b"qwerty")

It's only triggered when separator is bytes. And this can only happen when specifically using the new argument in the new patch. Though it's still less-than-ideal so I'm glad Petr caught it.

Edit: Hmm considering this is bugfix. I'm guessing backport to 3.8 only?

[github-actions]

This PR is stale because it has been open for 30 days with no activity.

[Fidget-Spinner]

A very gentle ping @orsenthil

[orsenthil]

Oh, thanks @Fidget-Spinner. Sorry, I missed this.

[bedevere-bot]

@orsenthil: Please replace # with GH- in the commit message next time. Thanks!

[miss-islington]

Thanks @Fidget-Spinner for the PR, and @orsenthil for merging it 🌮🎉.. I'm working now to backport this PR to: 3.9.
🐍🍒⛏🤖

[miss-islington]

Thanks @Fidget-Spinner for the PR, and @orsenthil for merging it 🌮🎉.. I'm working now to backport this PR to: 3.8.
🐍🍒⛏🤖

[bedevere-bot]

GH-25344 is a backport of this pull request to the 3.9 branch.

[bedevere-bot]

GH-25345 is a backport of this pull request to the 3.8 branch.