Fixes unstable next breaking version when major is 0 (#475)

src/poetry/core/semver/version.py

@@ -20,7 +20,7 @@
 @dataclasses.dataclass(frozen=True)
 class Version(PEP440Version, VersionRangeConstraint):
     """
-    A parsed semantic version number.
+    A version constraint representing a single version.
     """
 
     @property
@@ -32,21 +32,17 @@ def stable(self) -> Version:
         if self.is_stable():
             return self
 
-        return self.next_patch()
+        post = self.post if self.pre is None else None
+        return Version(release=self.release, post=post, epoch=self.epoch)
 
     def next_breaking(self) -> Version:
-        if self.major == 0:
-            if self.minor is not None and self.minor != 0:
-                return self.next_minor()
+        if self.major > 0 or self.minor is None:
+            return self.stable.next_major()
 
-            if self.precision == 1:
-                return self.next_major()
-            elif self.precision == 2:
-                return self.next_minor()
+        if self.minor > 0 or self.patch is None:
+            return self.stable.next_minor()
 
-            return self.next_patch()
-
-        return self.stable.next_major()
+        return self.stable.next_patch()
 
     @property
     def min(self) -> Version:

tests/semver/test_helpers.py

@@ -244,6 +244,30 @@ def test_parse_constraint_tilde(input: str, constraint: VersionRange) -> None:
                 Version.from_parts(0, 0, 3), Version.from_parts(0, 0, 4), True
             ),
         ),
+        (
+            "^0.0.3-alpha.21",
+            VersionRange(
+                Version.from_parts(0, 0, 3, pre=ReleaseTag("alpha", 21)),
+                Version.from_parts(0, 0, 4),
+                True,
+            ),
+        ),
+        (
+            "^0.1.3-alpha.21",
+            VersionRange(
+                Version.from_parts(0, 1, 3, pre=ReleaseTag("alpha", 21)),
+                Version.from_parts(0, 2, 0),
+                True,
+            ),
+        ),
+        (
+            "^0.0.0-alpha.21",
+            VersionRange(
+                Version.from_parts(0, 0, 0, pre=ReleaseTag("alpha", 21)),
+                Version.from_parts(0, 0, 1),
+                True,
+            ),
+        ),
     ],
 )
 def test_parse_constraint_caret(input: str, constraint: VersionRange) -> None:
@@ -392,6 +416,15 @@ def test_parse_constraints_with_trailing_comma(
         ("^1", ">=1,<2"),
         ("^1.0", ">=1.0,<2.0"),
         ("^1.0.0", ">=1.0.0,<2.0.0"),
+        ("^1.0.0-alpha.1", ">=1.0.0-alpha.1,<2.0.0"),
+        ("^0", ">=0,<1"),
+        ("^0.1", ">=0.1,<0.2"),
+        ("^0.0.2", ">=0.0.2,<0.0.3"),
+        ("^0.1.2", ">=0.1.2,<0.2.0"),
+        ("^0-alpha.1", ">=0-alpha.1,<1"),
+        ("^0.1-alpha.1", ">=0.1-alpha.1,<0.2"),
+        ("^0.0.2-alpha.1", ">=0.0.2-alpha.1,<0.0.3"),
+        ("^0.1.2-alpha.1", ">=0.1.2-alpha.1,<0.2.0"),
         ("~1", ">=1,<2"),
         ("~1.0", ">=1.0,<1.1"),
         ("~1.0.0", ">=1.0.0,<1.1.0"),

tests/semver/test_version.py

@@ -49,6 +49,145 @@ def test_parse_invalid(value: str | None) -> None:
         Version.parse(value)  # type: ignore[arg-type]
 
 
+@pytest.mark.parametrize(
+    "version, expected",
+    [
+        ("1", "1"),
+        ("1.2", "1.2"),
+        ("1.2.3", "1.2.3"),
+        ("2!1.2.3", "2!1.2.3"),
+        ("1.2.3+local", "1.2.3+local"),
+        ("1.2.3.4", "1.2.3.4"),
+        ("1.dev0", "1"),
+        ("1.2dev0", "1.2"),
+        ("1.2.3dev0", "1.2.3"),
+        ("1.2.3.4dev0", "1.2.3.4"),
+        ("1.post1", "1.post1"),
+        ("1.2.post1", "1.2.post1"),
+        ("1.2.3.post1", "1.2.3.post1"),
+        ("1.post1.dev0", "1.post1"),
+        ("1.2.post1.dev0", "1.2.post1"),
+        ("1.2.3.post1.dev0", "1.2.3.post1"),
+        ("1.a1", "1"),
+        ("1.2a1", "1.2"),
+        ("1.2.3a1", "1.2.3"),
+        ("1.2.3.4a1", "1.2.3.4"),
+        ("1.a1.post2", "1"),
+        ("1.2a1.post2", "1.2"),
+        ("1.2.3a1.post2", "1.2.3"),
+        ("1.2.3.4a1.post2", "1.2.3.4"),
+        ("1.a1.post2.dev0", "1"),
+        ("1.2a1.post2.dev0", "1.2"),
+        ("1.2.3a1.post2.dev0", "1.2.3"),
+        ("1.2.3.4a1.post2.dev0", "1.2.3.4"),
+    ],
+)
+def test_stable(version: str, expected: str) -> None:
+    subject = Version.parse(version)
+
+    assert subject.stable.text == expected
+
+
+@pytest.mark.parametrize(
+    "version, expected",
+    [
+        ("1", "2"),
+        ("1.2", "2.0"),
+        ("1.2.3", "2.0.0"),
+        ("2!1.2.3", "2!2.0.0"),
+        ("1.2.3+local", "2.0.0"),
+        ("1.2.3.4", "2.0.0.0"),
+        ("1.dev0", "2"),
+        ("1.2dev0", "2.0"),
+        ("1.2.3dev0", "2.0.0"),
+        ("1.2.3.4dev0", "2.0.0.0"),
+        ("1.post1", "2"),
+        ("1.2.post1", "2.0"),
+        ("1.2.3.post1", "2.0.0"),
+        ("1.post1.dev0", "2"),
+        ("1.2.post1.dev0", "2.0"),
+        ("1.2.3.post1.dev0", "2.0.0"),
+        ("2.a1", "3"),
+        ("2.2a1", "3.0"),
+        ("2.2.3a1", "3.0.0"),
+        ("2.2.3.4a1", "3.0.0.0"),
+        ("2.a1.post2", "3"),
+        ("2.2a1.post2", "3.0"),
+        ("2.2.3a1.post2", "3.0.0"),
+        ("2.2.3.4a1.post2", "3.0.0.0"),
+        ("2.a1.post2.dev0", "3"),
+        ("2.2a1.post2.dev0", "3.0"),
+        ("2.2.3a1.post2.dev0", "3.0.0"),
+        ("2.2.3.4a1.post2.dev0", "3.0.0.0"),
+    ],
+)
+def test_next_breaking_for_major_over_0_results_into_next_major_and_preserves_precision(
+    version: str, expected: str
+) -> None:
+    subject = Version.parse(version)
+
+    assert subject.next_breaking().text == expected
+
+
+@pytest.mark.parametrize(
+    "version, expected",
+    [
+        ("0", "1"),
+        ("0.0", "0.1"),
+        ("0.2", "0.3"),
+        ("0.2.3", "0.3.0"),
+        ("2!0.2.3", "2!0.3.0"),
+        ("0.2.3+local", "0.3.0"),
+        ("0.2.3.4", "0.3.0.0"),
+        ("0.0.3.4", "0.0.4.0"),
+        ("0.dev0", "1"),
+        ("0.0dev0", "0.1"),
+        ("0.2dev0", "0.3"),
+        ("0.2.3dev0", "0.3.0"),
+        ("0.0.3dev0", "0.0.4"),
+        ("0.post1", "1"),
+        ("0.0.post1", "0.1"),
+        ("0.2.post1", "0.3"),
+        ("0.2.3.post1", "0.3.0"),
+        ("0.0.3.post1", "0.0.4"),
+        ("0.post1.dev0", "1"),
+        ("0.0.post1.dev0", "0.1"),
+        ("0.2.post1.dev0", "0.3"),
+        ("0.2.3.post1.dev0", "0.3.0"),
+        ("0.0.3.post1.dev0", "0.0.4"),
+        ("0.a1", "1"),
+        ("0.0a1", "0.1"),
+        ("0.2a1", "0.3"),
+        ("0.2.3a1", "0.3.0"),
+        ("0.2.3.4a1", "0.3.0.0"),
+        ("0.0.3.4a1", "0.0.4.0"),
+        ("0.a1.post2", "1"),
+        ("0.0a1.post2", "0.1"),
+        ("0.2a1.post2", "0.3"),
+        ("0.2.3a1.post2", "0.3.0"),
+        ("0.2.3.4a1.post2", "0.3.0.0"),
+        ("0.0.3.4a1.post2", "0.0.4.0"),
+        ("0.a1.post2.dev0", "1"),
+        ("0.0a1.post2.dev0", "0.1"),
+        ("0.2a1.post2.dev0", "0.3"),
+        ("0.2.3a1.post2.dev0", "0.3.0"),
+        ("0.2.3.4a1.post2.dev0", "0.3.0.0"),
+        ("0.0.3.4a1.post2.dev0", "0.0.4.0"),
+        ("0-alpha.1", "1"),
+        ("0.0-alpha.1", "0.1"),
+        ("0.2-alpha.1", "0.3"),
+        ("0.0.1-alpha.2", "0.0.2"),
+        ("0.1.2-alpha.1", "0.2.0"),
+    ],
+)
+def test_next_breaking_for_major_0_is_treated_with_more_care_and_preserves_precision(
+    version: str, expected: str
+) -> None:
+    subject = Version.parse(version)
+
+    assert subject.next_breaking().text == expected
+
+
 @pytest.mark.parametrize(
     "versions",
     [

tests/version/pep440/test_version.py

@@ -226,6 +226,88 @@ def test_next_prerelease(version: str, expected: str) -> None:
     assert v.next_prerelease().text == expected
 
 
+@pytest.mark.parametrize(
+    "version, expected",
+    [
+        ("1", True),
+        ("1.2", True),
+        ("1.2.3", True),
+        ("2!1.2.3", True),
+        ("1.2.3+local", True),
+        ("1.2.3.4", True),
+        ("1.dev0", False),
+        ("1.2dev0", False),
+        ("1.2.3dev0", False),
+        ("1.2.3.4dev0", False),
+        ("1.post1", True),
+        ("1.2.post1", True),
+        ("1.2.3.post1", True),
+        ("1.post1.dev0", False),
+        ("1.2.post1.dev0", False),
+        ("1.2.3.post1.dev0", False),
+        ("1.a1", False),
+        ("1.2a1", False),
+        ("1.2.3a1", False),
+        ("1.2.3.4a1", False),
+        ("1.a1.post2", False),
+        ("1.2a1.post2", False),
+        ("1.2.3a1.post2", False),
+        ("1.2.3.4a1.post2", False),
+        ("1.a1.post2.dev0", False),
+        ("1.2a1.post2.dev0", False),
+        ("1.2.3a1.post2.dev0", False),
+        ("1.2.3.4a1.post2.dev0", False),
+    ],
+)
+def test_is_stable(version: str, expected: bool) -> None:
+    subject = PEP440Version.parse(version)
+
+    assert subject.is_stable() == expected
+    assert subject.is_unstable() == (not expected)
+
+
+@pytest.mark.parametrize(
+    "version, expected",
+    [
+        ("0", True),
+        ("0.2", True),
+        ("0.2.3", True),
+        ("2!0.2.3", True),
+        ("0.2.3+local", True),
+        ("0.2.3.4", True),
+        ("0.dev0", False),
+        ("0.2dev0", False),
+        ("0.2.3dev0", False),
+        ("0.2.3.4dev0", False),
+        ("0.post1", True),
+        ("0.2.post1", True),
+        ("0.2.3.post1", True),
+        ("0.post1.dev0", False),
+        ("0.2.post1.dev0", False),
+        ("0.2.3.post1.dev0", False),
+        ("0.a1", False),
+        ("0.2a1", False),
+        ("0.2.3a1", False),
+        ("0.2.3.4a1", False),
+        ("0.a1.post2", False),
+        ("0.2a1.post2", False),
+        ("0.2.3a1.post2", False),
+        ("0.2.3.4a1.post2", False),
+        ("0.a1.post2.dev0", False),
+        ("0.2a1.post2.dev0", False),
+        ("0.2.3a1.post2.dev0", False),
+        ("0.2.3.4a1.post2.dev0", False),
+    ],
+)
+def test_is_stable_all_major_0_versions_are_treated_as_normal_versions(
+    version: str, expected: bool
+) -> None:
+    subject = PEP440Version.parse(version)
+
+    assert subject.is_stable() == expected
+    assert subject.is_unstable() == (not expected)
+
+
 @pytest.mark.parametrize(
     "version, expected",
     [