[Distutils] [issue148] setup_requires dependency removal causes installation failure

[Ian Wienand]

New submission from Ian Wienand:

I noticed the following issue installing the keyring package [1]

---
Downloading/unpacking keyring
  Downloading keyring-1.2.2.zip (79Kb): 79Kb downloaded
  Running setup.py egg_info for package keyring
    zip_safe flag not set; analyzing archive contents...
    
    Installed /tmp/easy_install-u0ESXQ/pytest-runner-1.2/hgtools-2.0.3-py2.6.egg
    
    Installed /root/build/keyring/pytest_runner-1.2-py2.6.egg
    Traceback (most recent call last):
      File "<string>", line 14, in <module>
      File "/root/build/keyring/setup.py", line 114, in <module>
        setup_mod.setup(**setup_params)
      File "/usr/lib64/python2.6/distutils/core.py", line 152, in setup
        dist.run_commands()
      File "/usr/lib64/python2.6/distutils/dist.py", line 975, in run_commands
        self.run_command(cmd)
      File "/usr/lib64/python2.6/distutils/dist.py", line 995, in run_command
        cmd_obj.run()
      File "<string>", line 12, in replacement_run
      File "/usr/lib/python2.6/site-packages/setuptools/command/egg_info.py", line 254, in find_sources
        mm.run()
      File "/usr/lib/python2.6/site-packages/setuptools/command/egg_info.py", line 308, in run
        self.add_defaults()
      File "/usr/lib/python2.6/site-packages/setuptools/command/egg_info.py", line 335, in add_defaults
        rcfiles = list(walk_revctrl())
      File "/usr/lib/python2.6/site-packages/setuptools/command/sdist.py", line 46, in walk_revctrl
        for item in ep.load()(dirname):
      File "/usr/lib/python2.6/site-packages/pkg_resources.py", line 1948, in load
        entry = __import__(self.module_name, globals(),globals(), ['__name__'])
    ImportError: No module named hgtools.plugins
    Complete output from command python setup.py egg_info:
    zip_safe flag not set; analyzing archive contents...
---

The dependency chain works out to be

keyring -> pytest-runner -> hgtools

hgtools is a "setup_requires" dependency for pytest-runner.  This
means the following code is run:

/usr/lib/python2.6/site-packages/setuptools/dist.py
---
class Distribution(_Distribution):
    def __init__():
     ...
        if attrs and 'setup_requires' in attrs:
            self.fetch_build_eggs(attrs.pop('setup_requires'))

    def fetch_build_eggs(self, requires):
        """Resolve pre-setup requirements"""
        from pkg_resources import working_set, parse_requirements
        for dist in working_set.resolve(
            parse_requirements(requires), installer=self.fetch_build_egg
        ):
            working_set.add(dist)
---

That goes fine, hgtools gets installed into whatever /tmp directory, is added to sys.path and pytest-runner is happy.

However, the temporary hgtools has registered some entry points with its distribution object in working_set.  It then disappears but doesn't remove itself.  Later on in sdist.py we have

---
def walk_revctrl(dirname=''):
    """Find all files under revision control"""
    for ep in pkg_resources.iter_entry_points('setuptools.file_finders'):
        for item in ep.load()(dirname):
            yield item
----

pkg_resources.iter_entry_points walks all the distribution objects in working_set, finds hgtools' entry points for this "setuptools.file_finders" stuff, tries to call it and a backtrace ensues because that temporary directory with hgtools has now gone.

This also explains why it works when run the second time around; pytest-runner is already there, so we don't need to look at its setup_requires and the problematic distribution doesn't get added.

Somehow or other, hgtools needs to get removed from the working_set in dist.py before it is removed?


[1] https://bugzilla.redhat.com/show_bug.cgi?id=924038

----------
messages: 709
nosy: iwienand
priority: bug
status: unread
title: setup_requires dependency removal causes installation failure

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Setuptools tracker <setuptools at bugs.python.org>
<http://bugs.python.org/setuptools/issue148>
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