version: fix zero padding for version comparisons

src/poetry/core/version/pep440/segments.py

@@ -50,11 +50,11 @@ def __post_init__(self) -> None:
         ]
         object.__setattr__(self, "text", ".".join(parts))
         object.__setattr__(self, "precision", len(parts))
-        object.__setattr__(
-            self,
-            "_compare_key",
-            (self.major, self.minor or 0, self.patch or 0, *self.extra),
-        )
+
+        compare_key = [self.major, self.minor or 0, self.patch or 0, *self.extra]
+        while compare_key and compare_key[-1] == 0:
+            del compare_key[-1]
+        object.__setattr__(self, "_compare_key", tuple(compare_key))
 
     @classmethod
     def from_parts(cls, *parts: int) -> Release:

tests/constraints/version/test_version.py

@@ -287,6 +287,7 @@ def test_equality() -> None:
 def test_allows() -> None:
     v = Version.parse("1.2.3")
     assert v.allows(v)
+    assert not v.allows(Version.parse("1.2"))
     assert not v.allows(Version.parse("2.2.3"))
     assert not v.allows(Version.parse("1.3.3"))
     assert not v.allows(Version.parse("1.2.4"))
@@ -296,6 +297,33 @@ def test_allows() -> None:
     assert v.allows(Version.parse("1.2.3+build"))
 
 
+@pytest.mark.parametrize(
+    ("version1", "version2"),
+    [
+        ("1", "1.0"),
+        ("1", "1.0.0"),
+        ("1", "1.0.0.0"),
+        ("1.2", "1.2.0"),
+        ("1.2", "1.2.0.0"),
+        ("1.2", "1.2.0.0.0"),
+        ("1.2.3", "1.2.3.0"),
+        ("1.2.3", "1.2.3.0.0"),
+        ("1.2.3.4", "1.2.3.4.0"),
+        ("1.2.3.4", "1.2.3.4.0.0"),
+        ("1.2.3.4a1", "1.2.3.4.0a1"),
+    ],
+)
+def test_allows_zero_padding(version1: str, version2: str) -> None:
+    v1 = Version.parse(version1)
+    v2 = Version.parse(version2)
+    assert v1.allows(v2)
+    assert v2.allows(v1)
+    assert v1.allows_all(v2)
+    assert v2.allows_all(v1)
+    assert v1.allows_any(v2)
+    assert v2.allows_any(v1)
+
+
 def test_allows_with_local() -> None:
     v = Version.parse("1.2.3+build.1")
     assert v.allows(v)

tests/version/pep440/test_segments.py

@@ -8,11 +8,39 @@
 
 
 def test_release_post_init_minor_and_patch() -> None:
+    """
+    Minor and patch must not be None but zero if there are extra parts.
+    """
     release = Release(1, extra=(0,))
     assert release.minor == 0
     assert release.patch == 0
 
 
+def test_release_post_init_zero_version() -> None:
+    """
+    Smoke test for edge case (because zeros are stripped for comparison).
+    """
+    Release(0)
+
+
+@pytest.mark.parametrize("precision1", range(1, 6))
+@pytest.mark.parametrize("precision2", range(1, 6))
+def test_release_equal_zero_padding(precision1: int, precision2: int) -> None:
+    release1 = Release.from_parts(*range(1, precision1 + 1))
+    if precision1 > precision2:
+        # e.g. 1.2.3 != 1.2
+        release2 = Release.from_parts(*range(1, precision2 + 1))
+        assert release1 != release2
+        assert release2 != release1
+    else:
+        # e.g. 1.2 == 1.2.0
+        release2 = Release.from_parts(
+            *range(1, precision1 + 1), *[0] * (precision2 - precision1)
+        )
+        assert release1 == release2
+        assert release2 == release1
+
+
 @pytest.mark.parametrize(
     "parts,result",
     [