From 51f6aa8b434793487d3356f10100d5aa9396bfce Mon Sep 17 00:00:00 2001
From: Alessio Quaglino <quaglino@google.com>
Date: Tue, 4 Mar 2025 08:42:18 -0800
Subject: [PATCH] Store assets by address instead of value in MjSpec.

PiperOrigin-RevId: 733343350
Change-Id: I42ee2a184ebff37a080dace0422bb61e1ba53527
---
 python/mujoco/specs_test.py | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/python/mujoco/specs_test.py b/python/mujoco/specs_test.py
index e400347e..ec2c0fbb 100644
--- a/python/mujoco/specs_test.py
+++ b/python/mujoco/specs_test.py
@@ -14,6 +14,7 @@
 # ==============================================================================
 """Tests for mjSpec bindings."""
 
+import gc
 import inspect
 import os
 import textwrap
@@ -750,6 +751,10 @@ class SpecsTest(absltest.TestCase):
     model = spec.compile()
     self.assertEqual(model.nmeshvert, 8)
     self.assertEqual(spec.assets['cube.obj'], cube)
+    self.assertIs(
+        spec.assets['cube.obj'], cube,
+        'Asset dict should contain a reference, not a copy'
+    )
 
     xml = """
     <mujoco model="test">
@@ -766,6 +771,13 @@ class SpecsTest(absltest.TestCase):
     model = spec.compile()
     self.assertEqual(model.nmeshvert, 8)
     self.assertEqual(spec.assets['cube.obj'], cube)
+    self.assertIs(
+        spec.assets['cube.obj'], cube,
+        'Asset dict should contain a reference, not a copy'
+    )
+    del assets
+    gc.collect()
+    self.assertEqual(spec.assets['cube.obj'], cube)
 
   def test_include(self):
     included_xml = """