From fbbf1573a5547b115c2411ccb6a398eff71d3b33 Mon Sep 17 00:00:00 2001
From: Tim Jenness <tjenness@lsst.org>
Date: Fri, 16 Jun 2023 10:39:47 -0700
Subject: [PATCH] Add explicit deep copy support

---
 python/lsst/pipe/base/_quantumContext.py | 4 ++++
 tests/test_pipelineTask.py               | 3 +++
 2 files changed, 7 insertions(+)

diff --git a/python/lsst/pipe/base/_quantumContext.py b/python/lsst/pipe/base/_quantumContext.py
index 09b9a549..01da1204 100644
--- a/python/lsst/pipe/base/_quantumContext.py
+++ b/python/lsst/pipe/base/_quantumContext.py
@@ -66,6 +66,10 @@ def __post_init__(self) -> None:
                 max_mem = max_mem.to(u.B)
             object.__setattr__(self, "max_mem", max_mem)
 
+    def __deepcopy__(self, memo: Any) -> ExecutionResources:
+        """Deep copy returns itself because the class is frozen."""
+        return self
+
     def _reduce_kwargs(self) -> dict[str, Any]:
         """Return a dict of the keyword arguments that should be used
         by `__reduce__`.
diff --git a/tests/test_pipelineTask.py b/tests/test_pipelineTask.py
index 87ddd285..c0beff0d 100644
--- a/tests/test_pipelineTask.py
+++ b/tests/test_pipelineTask.py
@@ -22,6 +22,7 @@
 """Simple unit test for PipelineTask.
 """
 
+import copy
 import pickle
 import unittest
 from typing import Any
@@ -337,6 +338,8 @@ def test_ExecutionResources(self):
         self.assertEqual(res.max_mem.value, 512)
         self.assertEqual(pickle.loads(pickle.dumps(res)), res)
 
+        self.assertIs(res, copy.deepcopy(res))
+
         with self.assertRaises(u.UnitConversionError):
             pipeBase.ExecutionResources(max_mem=1 * u.m)