[4.6.0b0] MalformedVersionError

[dhirschfeld]

Since 4.6.0b0 didn't seem to work with my conda build I attempted to downgrade to the latest stable but got an error!

λ conda install conda=4.5.11
Collecting package metadata: failed

MalformedVersionError: Malformed version string '~': invalid character(s)

[dhirschfeld]

Some debug output:

<snip>
DEBUG conda.core.solve:solve_final_state(212): solving prefix C:\Miniconda3
  specs_to_remove: frozenset()
  specs_to_add: frozenset({MatchSpec("conda=4.5.11")})
  prune: False
Collecting package metadata: ...working... TRACE conda.gateways.disk.test:file_path_is_writable(25): checking path is writable C:\Miniconda3\pkgs\urls.txt
DEBUG conda.core.package_cache_data:_check_writable(252): package cache directory 'C:\Miniconda3\pkgs' writable: True
failed
Traceback (most recent call last):
  File "C:\Miniconda3\lib\site-packages\conda\models\version.py", line 38, in __call__
    return cls._cache_[arg]
KeyError: '~'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Miniconda3\lib\site-packages\conda\models\version.py", line 38, in __call__
    return cls._cache_[arg]
KeyError: '~'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Miniconda3\lib\site-packages\conda\exceptions.py", line 987, in __call__
    return func(*args, **kwargs)
  File "C:\Miniconda3\lib\site-packages\conda\cli\main.py", line 84, in _main
    exit_code = do_call(args, p)
  File "C:\Miniconda3\lib\site-packages\conda\cli\conda_argparse.py", line 81, in do_call
    exit_code = getattr(module, func_name)(args, parser)
  File "C:\Miniconda3\lib\site-packages\conda\cli\main_install.py", line 21, in execute
    install(args, parser, 'install')
  File "C:\Miniconda3\lib\site-packages\conda\cli\install.py", line 250, in install
    force_reinstall=context.force_reinstall or context.force,
  File "C:\Miniconda3\lib\site-packages\conda\core\solve.py", line 107, in solve_for_transaction
    force_remove, force_reinstall)
  File "C:\Miniconda3\lib\site-packages\conda\core\solve.py", line 145, in solve_for_diff
    force_remove)
  File "C:\Miniconda3\lib\site-packages\conda\core\solve.py", line 235, in solve_final_state
    ssc = self._collect_all_metadata(ssc)
  File "C:\Miniconda3\lib\site-packages\conda\core\solve.py", line 285, in _collect_all_metadata
    index, r = self._prepare(prepared_specs)
  File "C:\Miniconda3\lib\site-packages\conda\core\solve.py", line 667, in _prepare
    self.subdirs, prepared_specs)
  File "C:\Miniconda3\lib\site-packages\conda\core\index.py", line 204, in get_reduced_index
    push_record(prefix_rec)
  File "C:\Miniconda3\lib\site-packages\conda\core\index.py", line 190, in push_record
    combined_depends = record.combined_depends
  File "C:\Miniconda3\lib\site-packages\conda\models\records.py", line 314, in combined_depends
    result = {ms.name: ms for ms in MatchSpec.merge(self.depends)}
  File "C:\Miniconda3\lib\site-packages\conda\models\match_spec.py", line 443, in merge
    match_specs = tuple(cls(s) for s in match_specs if s)
  File "C:\Miniconda3\lib\site-packages\conda\models\match_spec.py", line 443, in <genexpr>
    match_specs = tuple(cls(s) for s in match_specs if s)
  File "C:\Miniconda3\lib\site-packages\conda\models\match_spec.py", line 50, in __call__
    return super(MatchSpecType, cls).__call__(**parsed)
  File "C:\Miniconda3\lib\site-packages\conda\models\match_spec.py", line 172, in __init__
    self._match_components = self._build_components(**kwargs)
  File "C:\Miniconda3\lib\site-packages\conda\models\match_spec.py", line 381, in _build_components
    return frozendict(_make_component(key, value) for key, value in iteritems(kwargs))
  File "C:\Miniconda3\lib\site-packages\conda\models\match_spec.py", line 381, in <genexpr>
    return frozendict(_make_component(key, value) for key, value in iteritems(kwargs))
  File "C:\Miniconda3\lib\site-packages\conda\models\match_spec.py", line 395, in _make_component
    matcher = _implementors[field_name](value)
  File "C:\Miniconda3\lib\site-packages\conda\models\version.py", line 40, in __call__
    val = cls._cache_[arg] = super(SingleStrArgCachingType, cls).__call__(arg)
  File "C:\Miniconda3\lib\site-packages\conda\models\version.py", line 486, in __init__
    vspec_str, matcher, is_exact = self.get_matcher(vspec)
  File "C:\Miniconda3\lib\site-packages\conda\models\version.py", line 557, in get_matcher
    self.matcher_vo = VersionOrder(vspec_str)
  File "C:\Miniconda3\lib\site-packages\conda\models\version.py", line 40, in __call__
    val = cls._cache_[arg] = super(SingleStrArgCachingType, cls).__call__(arg)
  File "C:\Miniconda3\lib\site-packages\conda\models\version.py", line 179, in __init__
    raise MalformedVersionError(vstr, "invalid character(s)")
conda.models.version.MalformedVersionError: Malformed version string '~': invalid character(s)

[dhirschfeld]

Instrumenting self.depends from the failing MatchSpec.merge:

conda/conda/models/records.py

Lines 311 to 318 in 21a24f0

	@property
	def combined_depends(self):
	from .match_spec import MatchSpec
	result = {ms.name: ms for ms in MatchSpec.merge(self.depends)}
	result.update({ms.name: ms for ms in MatchSpec.merge(
	MatchSpec(spec, optional=True) for spec in self.constrains or ()
	)})
	return tuple(itervalues(result))

...gives me:

################################################################################
# self.depends = ('appdirs ~=1.4.3', 'python 3.6.*', 'pytz', 'setuptools', 'six ~=1.10')
################################################################################

[dhirschfeld]

I was eventually able to downgrade by patching the function to replace ~= with >= 😌

...though it doesn't seem to be functional :/

[kalefranz]

Do you know what package that was?

[dhirschfeld]

Sorry, I'm not sure - I probably should have printed repr(self) too I guess.

I'm currently still trying to install 4.5.11 - after upgrading conda doesn't seem to like downgrading again :/

[dhirschfeld]

Let me know if you need more debug info and I can try and reproduce since my current env is basically stuffed :|

[kalefranz]

What channels were you using at the time? And what platform?

And I hear you on the downgrade thing. I do want the ratcheting effect that you're running into for the general case, but we need to provide an escape hatch for users like you :)

[kalefranz]

I can't figure out where these ~= operators are coming from. I originally thought this was probably related to #7761, but now it doesn't appear so. This is happens when directly reading repodata it appears, so those operators must actually be used in packages somewhere.

[kalefranz]

While I'd still like to understand where the ~= was coming from, I think #7780 should take care of everything here. Including a new config parameter allow_conda_downgrades (for now undocumented).

[mariusvniekerk]

~= is almost certainly from some pip installed thing?

[jorisvandenbossche]

Not sure it is helpful (it is a different error message, and I also can't further debug at the moment), but I ran into a similar issue last week when conda updated to 4.6.

I got the following when trying to go back to 4.5:

(base) joris@joris-XPS-13-9350:~/scipy$ conda install conda=4.5
Collecting package metadata: / WARNING conda.core.index:push_record(193): Skipping conda-forge/linux-64::ipywidgets-5.2.3-py27_0 due to InvalidVersionSpecError: ==1.*
WARNING conda.core.index:push_record(193): Skipping conda-forge/linux-64::ipywidgets-5.2.3-py36_0 due to InvalidVersionSpecError: ==1.*
WARNING conda.core.index:push_record(193): Skipping conda-forge/linux-64::ipywidgets-5.2.3-py35_0 due to InvalidVersionSpecError: ==1.*
done
Solving environment: failed

InvalidVersionSpecError: Invalid version spec: ==1.*

It seemed that if I removed conda-forge and conda-canary channels from my condarc file, the problem went away and I could downgrade conda again / install other packages again.

[kalefranz]

@jorisvandenbossche The bulk of what you're seeing should just be warnings, but I don't know why your environment failed to solve. Can you provide the output of conda install conda=4.5 -vv?

[kalefranz]

Ok, here's the PEP definition for the ~= operator: https://www.python.org/dev/peps/pep-0440/#compatible-release

[kalefranz]

There's also ===, which we never implemented support for.

[dhirschfeld]

@jorisvandenbossche ipywidgets should be fixed:

conda-forge/ipywidgets-feedstock#51

[jorisvandenbossche]

That seems to be the case, as I can no longer reproduce it!

[dhirschfeld]

FWIW the culprit was fs:

PrefixRecord(
    name='fs',
    version='2.0.24',
    build='pypi_0',
    build_number=0,
    channel=Channel("pypi"),
    subdir='pypi',
    fn='fs-2.0.24.dist-info',
    depends=('appdirs ~=1.4.3', 'python 3.6.*', 'pytz', 'setuptools', 'six ~=1.10'), 
    constrains=(),
    package_type='virtual_python_wheel',
	<snip>
)

[github-actions]

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