Beets: Errors when installed munkres is > 1.0.x

[Freso]

Problem

When invoking beets, beets errors out on munkres versions newer than 1.0.x. This was introduced by https://github.com/beetbox/beets/pull/3146.

Running this command in verbose (-vv) mode:

> beet -vv import .
Traceback (most recent call last):
  File "/usr/lib/python3.7/site-packages/pkg_resources/__init__.py", line 583, in _build_master
    ws.require(__requires__)
  File "/usr/lib/python3.7/site-packages/pkg_resources/__init__.py", line 900, in require
    needed = self.resolve(parse_requirements(requirements))
  File "/usr/lib/python3.7/site-packages/pkg_resources/__init__.py", line 791, in resolve
    raise VersionConflict(dist, req).with_context(dependent_req)
pkg_resources.ContextualVersionConflict: (munkres 1.1.2 (/usr/lib/python3.7/site-packages), Requirement.parse('munkres~=1.0.0'), {'beets'})

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/bin/beet", line 6, in <module>
    from pkg_resources import load_entry_point
  File "/usr/lib/python3.7/site-packages/pkg_resources/__init__.py", line 3191, in <module>
    @_call_aside
  File "/usr/lib/python3.7/site-packages/pkg_resources/__init__.py", line 3175, in _call_aside
    f(*args, **kwargs)
  File "/usr/lib/python3.7/site-packages/pkg_resources/__init__.py", line 3204, in _initialize_master_working_set
    working_set = WorkingSet._build_master()
  File "/usr/lib/python3.7/site-packages/pkg_resources/__init__.py", line 585, in _build_master
    return cls._build_from_requirements(__requires__)
  File "/usr/lib/python3.7/site-packages/pkg_resources/__init__.py", line 598, in _build_from_requirements
    dists = ws.resolve(reqs, Environment())
  File "/usr/lib/python3.7/site-packages/pkg_resources/__init__.py", line 786, in resolve
    raise DistributionNotFound(req, requirers)
pkg_resources.DistributionNotFound: The 'munkres~=1.0.0' distribution was not found and is required by beets

Setup

• OS: Linux (Arch Linux)
• Python version: 3.7.2
• beets version: 1.4.7.r359.g80f4f0a0-1 (from pacman -Qi output, beet --version also break due to munkres dependency)
• Turning off plugins made problem go away (yes/no): Didn't try.

My configuration (output of beet config) is:

Not relevant.

[Freso]

@jackwilsdon wrote:

We could add a conditional version dependency to require munkres 1.0.x on Python <3.5 and allow 1.1.x on >=3.5 if that would solve it @Freso?

I just looked at munkres’ source. Ugh. This would be a non-issue if they'd actually declared supported Python versions in their setup.{py,cfg}, then pip et al would automatically pull in the right version for their Python version without downstream like us having to work around this. :(

If a conditional can solve it, then yeah, I guess that's a fine way to go. Preferably with a note (# FIXME etc.) to remove the additional logic when 3.5 support is dropped.

[Freso]

Also reported this upstream: https://github.com/bmc/munkres/issues/31

[jackwilsdon]

I'm somewhat confused by your setup @Freso, how have you installed the new version of beets without munkres~=1.0.0? Surely when installing via pip it would have pulled the older munkres version? Do you have something else installed on your system which depends on the newer version of munkres?

I'm still up for adding a conditional version, just trying to work out why your machine has the wrong version.

[sampsyo]

Following up from @jackwilsdon's proposal in https://github.com/beetbox/beets/pull/3146#issuecomment-466988412, maybe the right policy would be:

• Python < 3.5 (including Python 2)? Then munkres~=1.0.0 (as it stands).
• Python 3.5? Then munkres!=1.1.0,!=1.1.1 (i.e., anything but the versions that used the 3.6-specific type annotations).
• Python > 3.5? Then munkres>=1.0.0 (anything goes, basically).

Would that cover all the cases?

[Freso]

@jackwilsdon I have beets installed through my package manager and the beets-git AUR package (that I maintain). This means that the version of munkres being installed is what Arch Linux's "python-munkres" package has.