pep440: support post/local for semver allows (#158)

This change ensures that post and local releases are taken into
consideration when checking if semver version instance allows
post and local build releases.

The following conditions now hold `poetry.core.semver.Version.allows`.

- `3.0.0` allows `3.0.0+local.1`, `3.0.0-1`
- `3.0.0+local.1` disallows `3.0.0+local.2`, allows `3.0.0-1`
- `3.0.0-1` disallows ``3.0.0`, `3.0.0+local.1`, allows `3.0.0-1+local.1`

Author: abn

poetry/core/semver/version.py

@@ -80,10 +80,29 @@ def is_empty(self) -> bool:
         return False
 
     def allows(self, version: "Version") -> bool:
-        return self == version
+        if version is None:
+            return False
+
+        _this, _other = self, version
+
+        # allow weak equality to allow `3.0.0+local.1` for `3.0.0`
+        if not _this.is_local() and _other.is_local():
+            _other = _other.without_local()
+        elif _this.is_local() and not _other.is_local():
+            _this = _this.without_local()
+
+        # allow weak equality to allow `3.0.0-1` for `3.0.0`
+        if not _this.is_postrelease() and _other.is_postrelease():
+            _other = _other.without_postrelease()
+        elif _this.without_postrelease() and not _other.without_postrelease():
+            _this = _this.without_postrelease()
+
+        return _this == _other
 
     def allows_all(self, other: "VersionTypes") -> bool:
-        return other.is_empty() or other == self
+        return other.is_empty() or (
+            self.allows(other) if isinstance(other, self.__class__) else other == self
+        )
 
     def allows_any(self, other: "VersionTypes") -> bool:
         return other.allows(self)
@@ -101,15 +120,15 @@ def union(self, other: "VersionTypes") -> "VersionTypes":
             return other
 
         if isinstance(other, VersionRangeConstraint):
-            if other.min == self:
+            if self.allows(other.min):
                 return VersionRange(
                     other.min,
                     other.max,
                     include_min=True,
                     include_max=other.include_max,
                 )
 
-            if other.max == self:
+            if self.allows(other.max):
                 return VersionRange(
                     other.min,
                     other.max,

tests/semver/test_version.py

@@ -113,7 +113,29 @@ def test_allows():
     assert not v.allows(Version.parse("1.3.3"))
     assert not v.allows(Version.parse("1.2.4"))
     assert not v.allows(Version.parse("1.2.3-dev"))
-    assert not v.allows(Version.parse("1.2.3+build"))
+    assert v.allows(Version.parse("1.2.3+build"))
+    assert v.allows(Version.parse("1.2.3-1"))
+    assert v.allows(Version.parse("1.2.3-1+build"))
+
+
+def test_allows_with_local():
+    v = Version.parse("1.2.3+build.1")
+    assert v.allows(v)
+    assert not v.allows(Version.parse("1.3.3"))
+    assert not v.allows(Version.parse("1.2.3-dev"))
+    assert not v.allows(Version.parse("1.2.3+build.2"))
+    assert v.allows(Version.parse("1.2.3-1"))
+    assert v.allows(Version.parse("1.2.3-1+build.1"))
+
+
+def test_allows_with_post():
+    v = Version.parse("1.2.3-1")
+    assert v.allows(v)
+    assert not v.allows(Version.parse("1.2.3"))
+    assert not v.allows(Version.parse("2.2.3"))
+    assert not v.allows(Version.parse("1.2.3-dev"))
+    assert not v.allows(Version.parse("1.2.3+build.2"))
+    assert v.allows(Version.parse("1.2.3-1+build.1"))
 
 
 def test_allows_all():