Fix sibling leak (#1590)

* add test

* fix + test

* fix fix

python/tests/test_array.py

@@ -2,6 +2,7 @@
 
 import operator
 import pickle
+import resource
 import sys
 import unittest
 import weakref
@@ -1928,6 +1929,25 @@ class TestArray(mlx_tests.MLXTestCase):
             x = mx.sin(x)
         mx.eval(x)
 
+    def test_siblings_without_eval(self):
+        def get_mem():
+            return resource.getrusage(resource.RUSAGE_SELF).ru_maxrss
+
+        key = mx.array([1, 2])
+
+        def t():
+            a, b = mx.split(key, 2)
+            a = mx.reshape(a, [])
+            b = mx.reshape(b, [])
+            return b
+
+        t()
+        expected = get_mem()
+        for _ in range(100):
+            t()
+        used = get_mem()
+        self.assertEqual(expected, used)
+
 
 if __name__ == "__main__":
     unittest.main()