Cannot install/build on Python 3.7-dev

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?

[ingydotnet]

PyYAML-3.13 has been released and it works with Python 3.7.

[lyricnz]

homebrew just updated python3 to 3.7, which caused this to become a Big Problem. Expect a bunch of people arriving here with the same issue.