[Python-Dev] TypeError messages

[Antoine Pitrou]

On Sat, 21 Feb 2015 21:39:32 +0000
MRAB <python at mrabarnett.plus.com> wrote:

> On 2015-02-21 17:14, Antoine Pitrou wrote:
> > On Fri, 20 Feb 2015 14:05:11 +0000
> > Brett Cannon <brett at python.org> wrote:
> >> On Thu Feb 19 2015 at 5:52:07 PM Serhiy Storchaka <storchaka at gmail.com>
> >> wrote:
> >>
> >> > Different patterns for TypeError messages are used in the stdlib:
> >> >
> >> >      expected X, Y found
> >> >      expected X, found Y
> >> >      expected X, but Y found
> >> >      expected X instance, Y found
> >> >      X expected, not Y
> >> >      expect X, not Y
> >> >      need X, Y found
> >> >      X is required, not Y
> >> >      Z must be X, not Y
> >> >      Z should be X, not Y
> >> >
> >> > and more.
> >> >
> >> > What the pattern is most preferable?
> >> >
> >>
> >> My preference is for "expected X, but found Y".
> >
> > If we are busy nitpicking, why are we saying "found Y"? Nothing was
> > *found* by the callee, it just *got* an argument.
> >
> Well, it depends on the reason for the message.
> 
> If you're passing an argument, then 'found' is the wrong word, but if
> you're parsing, say, a regex, then 'got' is the wrong word.

I don't think parsing would raise a TypeError, would it?

Regards

Antoine.