I was just saying that using the bool return value as an index is a bit
obscure, compared to using it as a condition in an if statement. But even
in the more common use, returning the matched string is still a chance in
behavior.
On Mon, Aug 9, 2021, 10:13 AM Chris Angelico <ros...@gmail.com> wrote:
> On Tue, Aug 10, 2021 at 12:03 AM Simão Afonso
> <simao.afo...@powertools-tech.com> wrote:
> >
> > On 2021-08-09 23:57:42, Chris Angelico wrote:
> > > On Mon, Aug 9, 2021 at 10:32 PM Samuel Freilich <sfreil...@google.com>
> wrote:
> > > > Even without it being used in as complicated a way as that it's
> still not backward compatible because of the trivial case, as
> foo.endswith("") is True.
> > >
> > > I was talking specifically about the original, which can be depended
> > > upon to return True or False. Changing the return value would break
> > > anything that depends on that.
> > >
> > > Not sure what you're referring to.
> >
> > I think this is the problem:
> >
> > > >>> "str".endswith("") is True
> > > True
> > > >>> "" is True
> > > <stdin>:1: SyntaxWarning: "is" with a literal. Did you mean "=="?
> > > False
> >
> > Even if you use the return value as a bool, it will flip the result.
>
> Yep, that's also a problem, but I don't understand why my comment
> about "can be used eg for indexing" was being quoted for context
> there. I was talking about how you could do something like this:
>
> protocol = ("ws:", "wss:")[url.startswith("https:")]
>
> If the return value changes, this breaks.
>
> ChrisA
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