Fix deep recursion with siblings (#1462)

* fix recursion with siblings

* fix

* add test

* increase tol

python/tests/test_array.py

@@ -1868,6 +1868,33 @@ class TestArray(mlx_tests.MLXTestCase):
         with self.assertRaises(ValueError):
             int(a)
 
+    def test_deep_graphs(self):
+        # The following tests should simply run cleanly without a segfault or
+        # crash due to exceeding recursion depth limits.
+
+        # Deep graph destroyed without eval
+        x = mx.array([1.0, 2.0])
+        for _ in range(100_000):
+            x = mx.sin(x)
+        del x
+
+        # Duplicate input deep graph destroyed without eval
+        x = mx.array([1.0, 2.0])
+        for _ in range(100_000):
+            x = x + x
+
+        # Deep graph with siblings destroyed without eval
+        x = mx.array([1, 2])
+        for _ in range(100_000):
+            x = mx.concatenate(mx.split(x, 2))
+        del x
+
+        # Deep graph with eval
+        x = mx.array([1.0, 2.0])
+        for _ in range(100_000):
+            x = mx.sin(x)
+        mx.eval(x)
+
 
 if __name__ == "__main__":
     unittest.main()