On 21/02/2019 07:32, Glyph wrote:
Yeah, this is part of carly, that I posted earlier. It stems from the
need to get the results of method calls when you have no reference to
the object being calls, or sometimes a result that's a deferred you
need to wait on, particularly in a test, but have no way of doing so.
I just can't parse this sentence.
Sorry, some typos in there are not helping ;-(
Breaking it down:
you have no reference to the object being calls,
How do you have no reference to the object being called? Aren't you
calling it?
That test case I linked to shows one example, the original ones were
from abstracting out JML's original post here:
https://jml.io/pages/how-to-disconnect-in-twisted-really.html
In any case you either have a Deferred or you don't; if you do, then
it's clear you should wait on it,
Yes, but where to wait is the question here. I'd like to leave that
choice to the user (see back in the thread for the details).
This is the test situation where I hit this issue:
https://github.com/cjw296/carly/blob/master/tests/test_untracked_deferred.py#L28-L35
I'd originally wanted to have that read:
@inlineCallbacks
def test1(self):
...
result = yield pita.asyncMethod.called()
with ShouldRaise(Exception(1)):
yield result
Now, which I'm actually happier with the end result here, I think the
above it legit, if unusual, and that assert trips it up.
Some type annotations might make it a bit clearer what the two states
here are :).
If those annotations were there, what would they look like? (I did link
to the whole test file, which has all the detail I think you could need,
it's pretty self contained and not that long)
As it is, it looks to me you want a Deferred to come *out*
of a 'yield', which should definitely never happen.
I disagree, in this specific case.
If this assert were
to be removed, it would be done in such a way that would implicitly wait
for the Deferred in question to fire: you should /never/ receive a
Deferred as an argument to a function, or as the result of an
(inlineCallbacks) 'yield' or (async def) 'await'. It breaks the whole
model of what 'awaiting' means.
Well, I'd agree 90% of the time, but test_untracked_deferred.py is where
that's no always true.
Anyway, I'm happy with the API I have now, and it neatly works around
that assert, so ¯\_(ツ)_/¯.
Chris
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