Narrow >V post-release exclusion to match spec

src/packaging/specifiers.py

@@ -52,15 +52,12 @@ def _public_version(version: Version) -> Version:
     return version.__replace__(local=None)
 
 
-def _base_version(version: Version) -> Version:
-    if (
-        version.pre is None
-        and version.post is None
-        and version.dev is None
-        and version.local is None
-    ):
-        return version
-    return version.__replace__(pre=None, post=None, dev=None, local=None)
+def _post_base(version: Version) -> Version:
+    """The version that *version* is a post-release of.
+
+    1.0.post1 -> 1.0, 1.0a1.post0 -> 1.0a1, 1.0.post0.dev1 -> 1.0.
+    """
+    return version.__replace__(post=None, dev=None, local=None)
 
 
 def _earliest_prerelease(version: Version) -> Version:
@@ -594,14 +591,12 @@ def _compare_greater_than(self, prospective: Version, spec_str: str) -> bool:
         if not prospective > spec:
             return False
 
-        # This special case is here so that, unless the specifier itself
-        # includes is a post-release version, that we do not accept
-        # post-release versions for the version mentioned in the specifier
-        # (e.g. >3.1 should not match 3.0.post0, but should match 3.2.post0).
+        # The spec says: ">V MUST NOT allow a post-release of the specified
+        # version unless the specified version is itself a post-release."
         if (
             not spec.is_postrelease
             and prospective.is_postrelease
-            and _base_version(prospective) == _base_version(spec)
+            and _post_base(prospective) == spec
         ):
             return False
 

tests/test_specifiers.py

@@ -780,6 +780,43 @@ def test_specifier_prereleases_detection(
             ("<=2.0.dev1", "1.0a1", None, None, True),
             ("<2.0", "2.0a1", None, None, False),
             ("<2.0a2", "2.0a1", None, None, True),
+            # >V.devN: post-releases of V.devN itself are excluded
+            # (V.devN can't have post-releases in PEP 440, so nothing
+            # to exclude; these just confirm ordering still works)
+            (">1.0.dev1", "1.0.dev0", None, None, False),
+            (">1.0.dev1", "1.0.dev2", None, None, True),
+            # >V.devN: post-releases of the base release are NOT
+            # post-releases of V.devN, so they are accepted
+            (">1.0.dev1", "1.0.post0", None, None, True),
+            (">1.0.dev1", "1.0.post1", None, None, True),
+            (">1.0.dev0", "1.0.post0", None, None, True),
+            # >V.preN: post-releases of the base release are NOT
+            # post-releases of V.preN, so they are accepted
+            (">1.0a1", "1.0.post0", None, None, True),
+            (">1.0b1", "1.0.post0", None, None, True),
+            (">1.0rc1", "1.0.post0", None, None, True),
+            # >V.preN: post-releases of the pre-release itself
+            # ARE excluded
+            (">1.0a1", "1.0a1.post0", None, None, False),
+            (">1.0b2", "1.0b2.post0", None, None, False),
+            (">1.0rc1", "1.0rc1.post0", None, None, False),
+            # >V.preN: post of a different pre is not a post-release
+            # of V.preN either
+            (">1.0a1", "1.0a2.post0", None, None, True),
+            (">1.0b1", "1.0b2.post0", None, None, True),
+            # >V.devN: non-post-release versions above V.devN
+            (">1.0.dev1", "1.0", None, None, True),
+            (">1.0.dev1", "1.0a1", None, None, True),
+            (">1.0.dev1", "1.1", None, None, True),
+            # >V (final): post-releases of V are still excluded
+            (">1.0", "1.0.post0", None, None, False),
+            (">1.0", "1.0.post1", None, None, False),
+            # >V (final): post-releases of a different base are fine
+            (">1.0", "2.0.post0", None, None, True),
+            (">1.0", "0.9.post0", None, None, False),
+            # >V.devN: locals and different bases
+            (">1.0.dev1", "1.1.post0", None, None, True),
+            (">1.0.dev1", "0.9.post0", None, None, False),
             # <V.postN: pre-releases of V.postN itself are excluded
             ("<1.0.post1", "1.0.post1.dev0", None, None, False),
             ("<1.0.post0", "1.0.post0.dev0", None, None, False),
@@ -1962,6 +1999,23 @@ def test_filter_exclusionary_bridges(
             (">=1!0,!=1!1.*,!=1!2.*,<1!3", True, "0!5.0", False),
             (">=1!0,!=1!1.*,!=1!2.*,<1!3", False, "1!0.5", True),
             (">=1!0,!=1!1.*,!=1!2.*,<1!3", False, "0!5.0", False),
+            # >V.devN combined with other specifiers: post-releases of
+            # the base release are accepted (they are not post-releases
+            # of V.devN).
+            (">1.0.dev1,==1.0.post0", None, "1.0.post0", True),
+            (">1.0.dev1,==1.0.post1", None, "1.0.post1", True),
+            (">1.0a1,==1.0.post0", None, "1.0.post0", True),
+            (">1.0.dev1,<=2.0", None, "1.0.post0", True),
+            (">1.0.dev1,<=2.0", None, "1.0", True),
+            # >V.preN: post of the pre-release itself is still excluded
+            (">1.0a1,<=2.0", True, "1.0a1.post0", False),
+            # With an upper bound that includes post-releases
+            (">1.0.dev1,<=1.0.post1", None, "1.0.post0", True),
+            (">1.0.dev1,<=1.0.post1", None, "1.0.post1", True),
+            (">1.0.dev1,<=1.0.post1", None, "1.0", True),
+            # != can remove some versions but post-releases still match
+            (">1.0.dev1,!=1.0,<=2.0", None, "1.0.post0", True),
+            (">1.0.dev1,!=1.0,!=1.0.post0,<=2.0", None, "1.0.post1", True),
             # <V.postN combined with other specifiers: pre-releases of
             # the base release are accepted (they are not pre-releases
             # of V.postN).