Deprecate the use of settings objects as context managers

[Zac-HD]

This API was a bad idea and should be removed, leaving settings to be determined by global state or decorators only. Using a settings object as a context manager is somewhat ambiguous (should it happen when the test is defined, or executed? certainly not within a test...) and just plain unnecessary.

[Zac-HD]

I tried just adding note_deprecation(...) to settings.__enter__ in _settings.py, and running the tests to see what breaks - the main task of this issue is to mechanically fix (or delete) our tests anywhere we're using this, and write a minor release note to explain to users that they should stop too.

Of our tests: 1115 failed, 743 passed. Not recommended for new contributors 😭

[alexwlchan]

I have some time for open-source this weekend, I might pick this up if nobody minds?

[Zac-HD]

If you have some time I'd love a review for my open PRs, and after (or before) that this one is all yours.

[alexwlchan]

👍 Any particular order, or oldest first?

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On 14 Jun 2018, at 21:35, Zac Hatfield-Dodds ***@***.***> wrote: If you have some time I'd love a review for my open PRs, and after (or before) that this one is all yours. — You are receiving this because you commented. Reply to this email directly, view it on GitHub, or mute the thread.

[Zac-HD]

Whatever works for you, but I'd suggest #1295, #1270, #1304, #1282 as a value-for-effort order. Thanks!

[alexwlchan]

I’m going to have a quick look at this.

[alexwlchan]

Ah, we use settings as a context manager in engine.py, where I think we do want to scope it to within a single run() method. That seems to be the root of most of the test breakages,

It’s not immediately obvious to me how we unpick it from there, but it’s been a while since I‘ve had to think about this code…

[Zac-HD]

The obvious option to me would be to add a private context manager function _with_settings(s), which does exactly the same thing but isn't public API - the alternative would be to manually pass the object around everywhere, and that gets ugly (and unmaintainable) very quickly.. Then it's just a matter of removing the context manager use from our docs and tests...

Do you still want to do this, or shall I?

[alexwlchan]

Do you still want to do this, or shall I?

I’m doing it. Hopefully at least a WIP PR by the end of the day.