10155 Add type hints to twisted.internet.task.

[wsanchez]

Add type hints for twisted.internet.task

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Merge pull request #123 from twisted/4356-branch-name-with-trac-id

Author: <github_username>, <github_usernames_if_more_authors>
Reviewer: <github_username>, <github_username_if_more_reviewers>
Fixes: ticket:<trac_ticket_number>, ticket:<another_if_more_in_one_PR>

Long description providing a summary of these changes.
(as long as you wish)

[adiroiban]

Looks good. Thanks!

I don't understand why TypeVar is used , so I only left a comment.

But if this is not reviewed by someone else in 2 weeks, I think that this can be merged.

---

In the docstring for errback I see

Passing a string as `fail' is deprecated, and will be punished with
a warning message.

I think that t his was already deprecated and maybe can be removed in this PR as a drive by.

[wiml]

This (and the return value) should be typed to indicate that the deferred fires with the same-type object as was passed to iterator, rather than just an arbitrary iterator

[wsanchez]

Can you suggest something, cuz I see an iterator of _TaskResultT… that's not specific enough?

[wsanchez]

@wiml poke poke

[wiml]

Same comment as for Cooperator.coiterate()

[wsanchez]

Same question…

[wsanchez]

Perhaps the question here is whether Iterator[_TaskResultT] used throughout CooperativeTask should instead be a _TaskIteratorT which is defined as TypeVar("_TaskIterableT", bound=Iterator[_TaskResultT]).

I'm not sure that the type of the Iterator (of _TaskResultT) being preserved here is important (that it: part of the API). And I'm not sure if _TaskIteratorT as I suggested above will accomplish that… @graingert: thoughts?

The documentation for coiterate just says that you get back a Deferred that fires on completion, not what that it's return is… so perhaps we should be actually typing return value as Deferred[None]?

[wsanchez]

I think I've addressed all of the comment except for @wiml's suggestion on coiterate, since I'm not sure what to change there.

[adiroiban]

Thanks for the update.

I think that this can be merged and there is not much use keep it pending without a review.

if someone is not happy with it, we can always have a followup PR.

Thanks again!

addressable later

[wsanchez]

Thanks