Allow expr_matches to better handle presence of extra data

oqpy/base.py

@@ -318,6 +318,8 @@ def expr_matches(a: Any, b: Any) -> bool:
 
     This bypasses calling ``__eq__`` on expr objects.
     """
+    if a is b:
+        return True
     if type(a) is not type(b):
         return False
     if isinstance(a, (list, np.ndarray)):
@@ -328,7 +330,7 @@ def expr_matches(a: Any, b: Any) -> bool:
         if a.keys() != b.keys():
             return False
         return all(expr_matches(va, b[k]) for k, va in a.items())
-    if hasattr(a, "__dict__"):
+    if hasattr(a, "__dict__") and type(a).__module__.startswith("oqpy"):
         return expr_matches(a.__dict__, b.__dict__)
     else:
         return a == b

tests/test_directives.py

@@ -2624,3 +2624,28 @@ def test_box_with_negative_duration():
     with pytest.raises(ValueError, match="Expected a non-negative duration, but got -4e-09"):
         with Box(prog, -4e-9):
             pass
+
+
+def test_expr_matches_handles_outside_data():
+    x1 = oqpy.FloatVar(3, name="x")
+    x2 = oqpy.FloatVar(3, name="x")
+    class MyEntity:
+        def __init__(self):
+            self.self_ref = self
+
+        def __eq__(self, other):
+            return True
+
+    x1._entity = MyEntity()
+    x2._entity = MyEntity()
+    assert oqpy.base.expr_matches(x1, x2)
+
+    class MyEntityNoEq:
+        def __init__(self):
+            self.self_ref = self
+        def __eq__(self, other):
+            raise RuntimeError("Eq not allowed")
+
+    x1._entity = MyEntityNoEq()
+    x2._entity = x1._entity
+    oqpy.base.expr_matches(x1, x2)