PEP 484: Add NoReturn type #218
Conversation
pep-0484.txt
Outdated
| The ``NoReturn`` type | ||
| --------------------- | ||
|
|
||
| ``typing`` module provides a special type ``NoReturn`` to annotate functions |
There was a problem hiding this comment.
I think a "The" before typing is required here.
pep-0484.txt
Outdated
|
|
||
| The ``NoReturn`` type is only valid as a return annotation of functions, | ||
| and considered an error if appears in other positions:: | ||
|
|
There was a problem hiding this comment.
if appears -> if it appears
pep-0484.txt
Outdated
| from typing import List, NoReturn | ||
|
|
||
| # All of the following are errors | ||
| def bad1(x: Noreturn) -> int: |
|
@DimitrisJim Thanks, fixed! |
pep-0484.txt
Outdated
| from typing import NoReturn | ||
|
|
||
| def stop() -> NoReturn: | ||
| raise Exception('no way') |
There was a problem hiding this comment.
Can you make this RuntimeException? raise Exception is such an anti-pattern I don't ever want to see it. :-)
pep-0484.txt
Outdated
| def stop() -> NoReturn: | ||
| raise Exception('no way') | ||
|
|
||
| Such return annotation is used in ``typeshed`` stubs for functions |
There was a problem hiding this comment.
Such return -> The NoReturn (mostly to avoid using "such" twice in one sentence :-).
Also, drop "in typeshed".
pep-0484.txt
Outdated
| if x > 0: | ||
| return x | ||
| stop() | ||
| return 'whatever works' # No error reported by checkers that |
There was a problem hiding this comment.
I find this debatable. Why would you have dead code that doesn't type-check? (Though maybe we've had this discussion already? I don't feel strongly about it, just wonder if maybe PEP 484 isn't the place to require this.)
There was a problem hiding this comment.
This is how mypy behaves (in fact, and in documentation). I softened the formulation in the new commit (as well as fixed two other things).
I don't have a strong opinion here either, but I think it maybe worth keeping mypy and PEP "in sync".
|
LGTM. Let's see if @markshannon has anything to say. |
|
@markshannon, calling twice? |
|
I'll just merge it. |
As discussed in python/typing#165, it is time to document the
NoReturntype.@gvanrossum Please take a look when you will have time.