Message 238637 - Python tracker

Message238637

Author	vstinner
Recipients	Claudiu.Popa, berker.peksag, brett.cannon, martin.panter, paul.moore, serhiy.storchaka, vstinner
Date	2015-03-20.10:16:23
SpamBayes Score	-1.0
Marked as misclassified	Yes
Message-id	<1426846584.17.0.944374682295.issue23681@psf.upfronthosting.co.za>
In-reply-to

Content
> This will help when someone writes something like `b'abcd'[2] == b'c'` What if someone writes line[-1] == 0 and line is a Unicode string? Should we emit a warning? I patched locally PyUnicode_RichCompare() to emit a warning. Hum, there are many warnings in argparse, http.client, and many other modules. I don't think that it's a good idea. It looks common to use a string for a sentinel (ex: state = "UNKNOWN") and then store an int (ex: state = 0). So comparison need to check the type (ex: isinstance(state, str) and state == "UNKNOWN") which is verbose and annoying. So no, we should not emit a warning :-)

Content

> This will help when someone writes something like `b'abcd'[2] == b'c'`

What if someone writes line[-1] == 0 and line is a Unicode string? Should we emit a warning?

I patched locally PyUnicode_RichCompare() to emit a warning. Hum, there are *many* warnings in argparse, http.client, and many other modules. I don't think that it's a good idea. It looks common to use a string for a sentinel (ex: state = "UNKNOWN") and then store an int (ex: state = 0). So comparison need to check the type (ex: isinstance(state, str) and state == "UNKNOWN") which is verbose and annoying.

So no, we should not emit a warning :-)

History
Date	User	Action	Args
2015-03-20 10:16:24	vstinner	set	recipients: + vstinner, brett.cannon, paul.moore, Claudiu.Popa, berker.peksag, martin.panter, serhiy.storchaka
2015-03-20 10:16:24	vstinner	set	messageid: <1426846584.17.0.944374682295.issue23681@psf.upfronthosting.co.za>
2015-03-20 10:16:24	vstinner	link	issue23681 messages
2015-03-20 10:16:23	vstinner	create