Hey Vladimir,
thanks for your considerations (relating to
http://pytest.org/dev/yieldfixture.html )
I am going to write a condensed reply to the few points where i disagree.
TLDR, i suggest to go for ``yield_fixture`` for pytest-2.4.
On Sat, Sep 28, 2013 at 22:29 +0200, Vladimir Keleshev wrote:
> Now, to comment on disadvantages:
> Yield-style fixtures present us with a superset of
> functionality of what return-style fixtures can achieve.
> I would even like to say that except for backwards-compatibility
> and user habit concerns, there is no need for return-style
> fixtures at all, if yield-style is available. So I would
> even argue that yield-style fixtures should take the main
> place in fixture documentation, and return-style fixtures
> mentioned for backwards compatibility (as funcargs are).
We can discuss this for 2.5 but not for 2.4. It's too
massive a change at this point. Also, from giving
courses to non-expert Pythonistas i know that "yield"
(as much as inheritance and other concepts) are not easy
concepts if if they are in computer science.
> 4.2 There is a high chance (in my experience) of mistyping
> `return` for `yield` like:
>
> @fixture
> def db():
> db = DB()
> return db
> db.clear()
>
> Even worse, this fixture could still appear to work, until
> some later time, when they system runs out of file
> descriptors, for example.
I think this error is highly unlikely because "return" for
almost everybody marks the end of the function.
So for pytest-2.4 we are left with a choice between a new
"yield_fixture" decorator or passing a ``yieldctx=True``
to the existing one. To make it easier for people to use
yield fixtures everywhere a decorator might be preferable.
You could write:
from pytest import yield_fixture as fixture
and use yield style everywhere. Not using yield in a
yield_fixture then would get you an error. Using
yield in a @pytest.fixture would work as before.
Originally i didn't want to go with a separate decorator
because it duplicates API and docstrings. But maybe this can
be mediated by just saying "same as pytest.fixture but
use 'yield' instead of 'return" for providing a fixture instance,
see http:/... for details."
Sounds like a plan?
holger
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