Canonicalize version before comparing specifiers (#283)

* Add failing tests

* Canonicalize version before comparing specifiers

* Update changelog

CHANGELOG.rst

@@ -4,7 +4,7 @@ Changelog
 *unreleased*
 ~~~~~~~~~~~~
 
-No unreleased changes.
+* Canonicalize version before comparing specifiers. (:issue:`282`)
 
 20.3 - 2020-03-05
 ~~~~~~~~~~~~~~~~~

packaging/specifiers.py

@@ -10,6 +10,7 @@
 
 from ._compat import string_types, with_metaclass
 from ._typing import MYPY_CHECK_RUNNING
+from .utils import canonicalize_version
 from .version import Version, LegacyVersion, parse
 
 if MYPY_CHECK_RUNNING:  # pragma: no cover
@@ -134,7 +135,8 @@ def __str__(self):
 
     def __hash__(self):
         # type: () -> int
-        return hash(self._spec)
+        operator, version = self._spec
+        return hash((operator, canonicalize_version(version)))
 
     def __eq__(self, other):
         # type: (object) -> bool
@@ -146,7 +148,7 @@ def __eq__(self, other):
         elif not isinstance(other, self.__class__):
             return NotImplemented
 
-        return self._spec == other._spec
+        return hash(self) == hash(other)
 
     def __ne__(self, other):
         # type: (object) -> bool

tests/test_specifiers.py

@@ -253,6 +253,12 @@ def test_comparison_true(self, left, right, op):
         assert op(left, Specifier(right))
         assert op(Specifier(left), right)
 
+    @pytest.mark.parametrize(("left", "right"), [("==2.8.0", "==2.8")])
+    def test_comparison_canonicalizes(self, left, right):
+        assert Specifier(left) == Specifier(right)
+        assert left == Specifier(right)
+        assert Specifier(left) == right
+
     @pytest.mark.parametrize(
         ("left", "right", "op"),
         itertools.chain(
@@ -961,6 +967,12 @@ def test_comparison_false(self, left, right, op):
         assert not op(left, SpecifierSet(right))
         assert not op(SpecifierSet(left), right)
 
+    @pytest.mark.parametrize(("left", "right"), [("==2.8.0", "==2.8")])
+    def test_comparison_canonicalizes(self, left, right):
+        assert SpecifierSet(left) == SpecifierSet(right)
+        assert left == SpecifierSet(right)
+        assert SpecifierSet(left) == right
+
     def test_comparison_non_specifier(self):
         assert SpecifierSet("==1.0") != 12
         assert not SpecifierSet("==1.0") == 12