PyException_Check and the Python Cassandra Driver

[abrugh]

Hi,

I think there's something wrong with Cython 0.25.0

How things should and do work:

• Make a new virtualenv
• pip install cython=0.24.1
• pip install cassandra-driver==3.7.0 (i tried 3.2.0 and 3.0.0 too)
• start python
• import cassandra.cluster

Where things break

• Make a new virtualenv
• pip install cython==0.25.0
• pip install cassandra-driver==3.7.0
• There will be an error about PyException_Check being implicitly declared but the install completes
• start python
• import cassandra.cluster
• You will set another error about PyException_Check

I honestly know nothing about Cython other than its a black box for making Python faster. But the fact that the only variable between the two scenarios above is the Cython version leads me to believe it's an issue with Cython and not the Cassandra driver.

Sorry of this doesn't meet criteria for a bug report. I'm happy to supply more info.

[jhgg]

Am having this exact same issue as of recent.

[jhgg]

It looks like this symbol has somehow appeared:

$ nm -g /home/deploy/virtualenvs/discord/local/lib/python2.7/site-packages/cassandra/cluster.so | grep PyException
                 U PyException_Check

This doesn't exist in the .so generated by cython 0.24.1

[ngoldbaum]

I've uploaded cluster.c here: https://gist.github.com/ngoldbaum/ff58cd6d51002ca6dc574e34ff5016cd

The problematic call to the nonexistent PyException_Check is being generated by code in the cython file that looks like this:

for exc in [f for f in results if isinstance(f, Exception)]:
    ...

[ngoldbaum]

In fact the following test code after being cythonized produces a call to PyException_Check:

results = ['foo', 'bar']

for exc in [f for f in results if isinstance(f, Exception)]:
    pass

$ cython test.pyx
$ ag PyException_Check test.c
998:    __pyx_t_6 = PyException_Check(__pyx_t_2);

[ngoldbaum]

Under cython 0.24.1 the same line looks like:

__pyx_t_6 = PyObject_IsInstance(__pyx_t_2, __pyx_builtin_Exception); if (unlikely(__pyx_t_6 == -1)) __PYX_ERR(0, 3, __pyx_L1_error)

[jhgg]

Fairly certain the bug is here:

cython/Cython/Compiler/PyrexTypes.py

Line 1218 in d8c5467

type_check = 'Py%s_Check' % type_name.capitalize()

It is generating the incorrect type check.

[ngoldbaum]

I think this was caused by b1d7b0d, ping @robertwb

[1st1]

Exactly the same problem in uvloop. Here's a Travis CI log.