[Twisted-Python] defer.inlineCallbacks dosn't work with cython, deferredGenerator does.

[Andrew Bennetts]

On Tue, Apr 10, 2012 at 12:41:17PM +0800, gelin yan wrote:
[…]
>     When trying to run inlineCallbacks with Cython, a TypeError would come
> out like:
> 
> TypeError: inlineCallbacks requires <built-in function test> to produce a
> generator; instead got <cy3.__pyx_scope_struct__test object at 0x02808848)
> 
> test is the function where inlineCallbacks uses.
> 
> It looks like cython changes the name test to  cy3.__pyx_scope_struct__test
> internally so generator can't work properly.

inlineCallbacks doesn't care what the function name is.  The problem here is
that inlineCallbacks expects to be passed a generator function[1], and instead
it is being passed some other sort of object.  The ugly cy3.__blah name is a red
herring.

-Andrew.

[1] Without the check that produces this error, a common and very confusing
    error is to decorate a non-generator function (i.e. one with no yield
    statement) with @inlineCallbacks, which would appear to work but would then
    mysteriously fail to do anything useful when executed.