dependency: do not implicitly allow prereleases since this is not PEP…

… 440 compliant and counterproductive (If only a prerelease fulfills a constraint, we choose it anyway. If a stable release fulfills a constraint, we shouldn't choose a prerelease if not explicitly requested.)

src/poetry/core/packages/dependency.py

@@ -13,7 +13,6 @@
 from packaging.utils import canonicalize_name
 
 from poetry.core.constraints.generic import parse_constraint as parse_generic_constraint
-from poetry.core.constraints.version import VersionRangeConstraint
 from poetry.core.constraints.version import parse_constraint
 from poetry.core.packages.dependency_group import MAIN_GROUP
 from poetry.core.packages.specification import PackageSpecification
@@ -71,15 +70,6 @@ def __init__(
             groups = [MAIN_GROUP]
 
         self._groups = frozenset(groups)
-
-        if (
-            isinstance(self._constraint, VersionRangeConstraint)
-            and self._constraint.min
-        ):
-            allows_prereleases = (
-                allows_prereleases or self._constraint.min.is_unstable()
-            )
-
         self._allows_prereleases = allows_prereleases
 
         self._python_versions = "*"

tests/packages/test_dependency.py

@@ -10,20 +10,22 @@
 
 
 @pytest.mark.parametrize(
-    "constraint,result",
+    "constraint",
     [
-        ("^1.0", False),
-        ("^1.0.dev0", True),
-        ("^1.0.0", False),
-        ("^1.0.0.dev0", True),
-        ("^1.0.0.alpha0", True),
-        ("^1.0.0.alpha0+local", True),
-        ("^1.0.0.rc0+local", True),
-        ("^1.0.0-1", False),
+        "^1.0",
+        "^1.0.dev0",
+        "^1.0.0",
+        "^1.0.0.dev0",
+        "^1.0.0.alpha0",
+        "^1.0.0.alpha0+local",
+        "^1.0.0.rc0+local",
+        "^1.0.0-1",
     ],
 )
-def test_allows_prerelease(constraint: str, result: bool) -> None:
-    assert Dependency("A", constraint).allows_prereleases() == result
+@pytest.mark.parametrize("allows_prereleases", [False, True])
+def test_allows_prerelease(constraint: str, allows_prereleases: bool) -> None:
+    dependency = Dependency("A", constraint, allows_prereleases=allows_prereleases)
+    assert dependency.allows_prereleases() == allows_prereleases
 
 
 def test_to_pep_508() -> None: