Jython: ImportError: No module named pkg_resources

[Stewori]

This is probably a Jython issue, but I'd like to have a fallback, since pytypes used to work with Jython apart from this.
As far as I understand, this is about some functionality of setuptools.
I didn't explicitly run setup.py on Jython, so something might be ill-configured.
However, I also didn't do such a thing on CPython, but there it runs out of the box.

How to fix it?

[Stewori]

Note: I tried it with jython-standalone and after using the installer.
With the installer, the error is different, but also biols down to pkg_resources:

'/home/stefan/jython2.7.1/bin/jython' tests/test_typechecker.py
Traceback (most recent call last):
  File "tests/test_typechecker.py", line 28, in <module>
    import pytypes
  File "/data/workspace/linux/pytypes/pytypes/__init__.py", line 560, in <module>
    from .typelogger import dump_cache, log_type, typelogged, typelogged_module, \
  File "/data/workspace/linux/pytypes/pytypes/typechecker.py", line 62, in _pytypes___import__
    res = _python___import__(name, globls, locls, fromlist, level)
  File "/data/workspace/linux/pytypes/pytypes/typelogger.py", line 30, in <module>
    import pkg_resources
  File "/data/workspace/linux/pytypes/pytypes/typechecker.py", line 62, in _pytypes___import__
    res = _python___import__(name, globls, locls, fromlist, level)
  File "/home/stefan/jython2.7.1/Lib/site-packages/pkg_resources/__init__.py", line 74, in <module>
    __import__('pkg_resources.extern.packaging.requirements')
  File "/data/workspace/linux/pytypes/pytypes/typechecker.py", line 62, in _pytypes___import__
    res = _python___import__(name, globls, locls, fromlist, level)
  File "/home/stefan/jython2.7.1/Lib/site-packages/pkg_resources/_vendor/packaging/requirements.py", line 9, in <module>
    from pkg_resources.extern.pyparsing import stringStart, stringEnd, originalTextFor, ParseException
  File "/data/workspace/linux/pytypes/pytypes/typechecker.py", line 62, in _pytypes___import__
    res = _python___import__(name, globls, locls, fromlist, level)
  File "/home/stefan/jython2.7.1/Lib/site-packages/pkg_resources/extern/__init__.py", line 43, in load_module
    __import__(extant)
  File "/home/stefan/jython2.7.1/Lib/site-packages/pkg_resources/extern/__init__.py", line 43, in load_module
    __import__(extant)
  File "/data/workspace/linux/pytypes/pytypes/typechecker.py", line 62, in _pytypes___import__
    res = _python___import__(name, globls, locls, fromlist, level)
  File "/home/stefan/jython2.7.1/Lib/site-packages/pkg_resources/_vendor/pyparsing.py", line 4720, in <module>
    _reBracketExpr = Literal("[") + Optional("^").setResultsName("negate") + Group( OneOrMore( _charRange | _singleChar ) ).setResultsName("body") + "]"
  File "/home/stefan/jython2.7.1/Lib/site-packages/pkg_resources/_vendor/pyparsing.py", line 1201, in setResultsName
    newself = self.copy()
  File "/home/stefan/jython2.7.1/Lib/site-packages/pkg_resources/_vendor/pyparsing.py", line 1160, in copy
    cpy = copy.copy( self )
  File "/home/stefan/jython2.7.1/Lib/copy.py", line 88, in copy
    rv = reductor(2)
  File "/data/workspace/linux/pytypes/pytypes/typechecker.py", line 62, in _pytypes___import__
    res = _python___import__(name, globls, locls, fromlist, level)
UnboundLocalError: local variable 'globls' referenced before assignment

If I remove pkg_resources from typelogger.py and set the version to some constant, both variants pass again.

[agronholm]

Jython does come with setuptools preinstalled, does it not? Installing it normally should make it work. I don't quite understand how the above error relates to pkg_resources.

[agronholm]

On second look, I see that importing pkg_resources causes the pytypes code to be imported. This is an import order issue. I'll look into it.

[Stewori]

That fixed the issue in principle, thank you.
However, it does not work with Jython-standalone.jar. I guess only the installer pre-installs setuptools.
I find the version string not important enough to break workability with jython-standalone.jar, so I will add some fallback (i.e. hard-coded version-string), unless we see a better solution.
Also, if we find a better solution over time, we can fix this later.

Do you know if it's possible to include Jython into travis tests?

[agronholm]

From Travis documentation:

Python 2.4 and Jython are not supported and there are no plans to support them in the future.

[agronholm]

So I'd say it's possible but not without some degree of hacking.

[agronholm]

There is an alternative to setuptools_scm, named pbr but it adds its own complexity to the build process. The upside is that it doesn't require pkg_resources at runtime.

[Stewori]

Okay, let's stick to setuptools_scm now. You'll probably not like the workaround in 872bd33, I also don't like it.
Still I think this hack is an acceptable price for getting it work with jython-standalone; at least at the moment.
If you don't have further concerns, I'd file a release soon (just writing the release notes...)

[agronholm]

Re: authors/notices: yeah, looks okay to me.

[agronholm]

Anyways, the hack is ugly but it doesn't matter if it's just temporary workaround.

[Stewori]

Seems like I broke travis with the assert. Removed it as of d07414f
This can be closed for now I'd say.