[Distutils] PEP 517 again

[Nathaniel Smith]

[removed Guido from CC]

On Aug 26, 2017 02:29, "Paul Moore" <p.f.moore at gmail.com> wrote:

On 26 August 2017 at 03:17, Guido van Rossum <guido at python.org> wrote:
> In pretty much any other context, if you have an operation that returns an
> regular value or an error value, the error value should be None.
(Exceptions
> include e.g. returning a non-negative int or -1 for errors, or True for
> success and False for errors.)

So, given that build_sdist returns the path of the newly built sdist,
the correct way to signal "I didn't manage to build a sdist" would be
to return None.

Now that it's put this way, it seems glaringly obvious to me that this
is the correct thing to do.


Eh... I would really prefer something that's (a) more explicit about what
specifically went wrong, and (b) harder to return by accident. It's not at
all obvious that if the list of requirements is 'None' that means 'this
build supports making sdists in general but cannot make them from this
source tree but might still be able to make a wheel'. And if you forget to
put in a return statement, then python returns None for you, which seems
like it could lead to some super confusing error modes.

-n
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