Mismatched comparison operations for Specifiers

[jbylund]

I just found this behavior a little surprising, and I feel like I'd be prone to make the assumption that a == b => not(a != b), doesn't seem to be mentioned in the docs: https://packaging.pypa.io/en/latest/specifiers.html

In [9]: lt4 = packaging.specifiers.Specifier("<4")

In [10]: lt4point0 = packaging.specifiers.Specifier("<4.0")

In [11]: lt4 == lt4point0
Out[11]: True

In [12]: lt4 != lt4point0
Out[12]: True

[pradyunsg]

packaging/packaging/specifiers.py

Line 143 in 2864588

return self._canonical_spec == other._canonical_spec

packaging/packaging/specifiers.py

Line 154 in 2864588

return self._spec != other._spec

Seems like a relatively simple fix -- both should use _canonical_spec. :)