Cannot install/build on Python 3.7-dev

[hugovk]

aws-cli depends on PyYAML>=3.10,<=3.12.

However, when running on Python 3.7-dev on Travis CI, PyYAML cannot be built:

    ext/_yaml.c:24215:11: error: ‘PyThreadState’ has no member named ‘exc_type’
         tstate->exc_type = local_type;
               ^
    ext/_yaml.c:24216:11: error: ‘PyThreadState’ has no member named ‘exc_value’
         tstate->exc_value = local_value;
               ^
    ext/_yaml.c:24217:11: error: ‘PyThreadState’ has no member named ‘exc_traceback’
         tstate->exc_traceback = local_tb;
               ^
    error: command 'gcc' failed with exit status 1

https://travis-ci.org/hugovk/aws-cli/jobs/335698944#L1466

This also affects other projects which depend on aws-cli, like pika:

  ext/_yaml.c: In function ‘__Pyx__ExceptionSave’:
  ext/_yaml.c:24143:19: error: ‘PyThreadState’ has no member named ‘exc_type’
       *type = tstate->exc_type;
                     ^
  ext/_yaml.c:24144:20: error: ‘PyThreadState’ has no member named ‘exc_value’
       *value = tstate->exc_value;
                      ^
  ext/_yaml.c:24145:17: error: ‘PyThreadState’ has no member named ‘exc_traceback’
       *tb = tstate->exc_traceback;
                   ^
  ext/_yaml.c: In function ‘__Pyx__ExceptionReset’:
  ext/_yaml.c:24152:22: error: ‘PyThreadState’ has no member named ‘exc_type’
     member named ‘exc_traceback’
       tstate->exc_traceback = local_tb;
             ^
  error: command 'gcc' failed with exit status 1
  
  ----------------------------------------
  Failed building wheel for PyYAML
  Running setup.py clean for PyYAML
Failed to build PyYAML

https://travis-ci.org/pika/pika/jobs/335516418

Any idea what's up?

[lukebakken]

There may be a workaround in aws/aws-cli#2290

Pinning awscli is a valid workaround, at least for Pika.

[The-Compiler]

I think the Cython code just needs to be regenerated to be compatible with Python 3.7? Installing from git+https://github.com/yaml/pyyaml.git instead seems to work for me.

See cython/cython#1955

[lmazuel]

I also have the same problem with 3.7-dev, but the error is not exactly the same (but considering the generic title of this issue, I think it's the right place :))
https://travis-ci.org/Azure/azure-sdk-for-python/jobs/341574626

../../../virtualenv/python3.7-dev/lib/python3.7/site-packages/yaml/__init__.py:70: in load
    loader = Loader(stream)
../../../virtualenv/python3.7-dev/lib/python3.7/site-packages/yaml/cyaml.py:31: in __init__
    CParser.__init__(self, stream)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
>   ???
E   AttributeError: 'str' object has no attribute 'read'
ext/_yaml.pyx:269: AttributeError

All other Python jobs are working as expected.

[jaraco]

Installing from [github] seems to work for me.

Same for me. pip install git+https://github.com/yaml/pyyaml.git. Of course, this workaround is a clumsy one, requiring manual intervention on any project adopting Python 3.7. It would be nice to see a updated release with wheels on PyPI to help ease the transition for other projects as they seek to support Python 3.7.

[wumpus]

Somewhat ironic, but the latest checkin to git 298e079 adds a fallback to the install process to use pure python if the C compile fails. So installing from git can have 2 pretty different outcomes, with different bugs.