Ensure version is hashable

Author: spoorcc

dfetch/manifest/version.py

@@ -25,8 +25,10 @@ def __eq__(self, other: Any) -> bool:
         return bool(self.branch == other.branch and self.revision == other.revision)
 
     def __hash__(self) -> int:
-        """Hash based on the underlying tuple value."""
-        return tuple.__hash__(self)
+        """Hash only fields that determine equality."""
+        if self.tag:
+            return hash(self.tag)
+        return hash((self.branch, self.revision))
 
     @property
     def field(self) -> tuple[str, str]:

tests/test_project_version.py

@@ -219,5 +219,8 @@ def test_version_comparison_with_non_version(other):
 
 def test_version_remains_hashable():
     """Defining __eq__ must not break hashing/set membership."""
-    version = Version(tag="1.0")
-    assert version in {version}
+    v1 = Version(tag="1.0")
+    v2 = Version(tag="1.0")
+    assert v1 == v2
+    assert hash(v1) == hash(v2)
+    assert v2 in {v1}