From 698df6729b113913813c575b9758c58d074fbf64 Mon Sep 17 00:00:00 2001
From: Sumit Saraswat <sumitsaraswat@MacSam.local>
Date: Fri, 9 Oct 2026 10:12:41 +0530
Subject: [PATCH 1/3] Fix memory leak: implement __deepcopy__ for ExtraCoords
 and GlobalCoords

---
 ndcube/extra_coords/extra_coords.py | 12 ++++++++++++
 ndcube/global_coords.py             | 12 ++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/ndcube/extra_coords/extra_coords.py b/ndcube/extra_coords/extra_coords.py
index bcbf6724d..c5450a18a 100644
--- a/ndcube/extra_coords/extra_coords.py
+++ b/ndcube/extra_coords/extra_coords.py
@@ -155,6 +155,18 @@ def __init__(self, ndcube=None):
         # We need a reference to the parent NDCube
         self._ndcube = ndcube
 
+    def __deepcopy__(self, memo):
+        import copy
+        cls = self.__class__
+        result = cls.__new__(cls)
+        memo[id(self)] = result
+        for k, v in self.__dict__.items():
+            if k == '_ndcube':
+                setattr(result, k, None)
+            else:
+                setattr(result, k, copy.deepcopy(v, memo))
+        return result
+
     @classmethod
     def from_lookup_tables(cls, names, pixel_dimensions, lookup_tables, physical_types=None):
         """
diff --git a/ndcube/global_coords.py b/ndcube/global_coords.py
index 3514a1799..fecc08057 100644
--- a/ndcube/global_coords.py
+++ b/ndcube/global_coords.py
@@ -88,6 +88,18 @@ def __init__(self, ndcube=None):
         self._ndcube = ndcube
         self._internal_coords = OrderedDict()
 
+    def __deepcopy__(self, memo):
+        import copy
+        cls = self.__class__
+        result = cls.__new__(cls)
+        memo[id(self)] = result
+        for k, v in self.__dict__.items():
+            if k == '_ndcube':
+                setattr(result, k, None)
+            else:
+                setattr(result, k, copy.deepcopy(v, memo))
+        return result
+
     @staticmethod
     def _convert_dropped_to_internal(dropped_dimensions):
         """

From 1f53a4e656897cdedbe6828a53ac0b0400a81afa Mon Sep 17 00:00:00 2001
From: Sumit Saraswat <sumitsaraswat@MacSam.local>
Date: Fri, 9 Oct 2026 10:29:47 +0530
Subject: [PATCH 2/3] style: sort imports and add changelog

---
 changelog/991.bugfix.rst            | 1 +
 ndcube/extra_coords/extra_coords.py | 3 ++-
 ndcube/global_coords.py             | 2 +-
 3 files changed, 4 insertions(+), 2 deletions(-)
 create mode 100644 changelog/991.bugfix.rst

diff --git a/changelog/991.bugfix.rst b/changelog/991.bugfix.rst
new file mode 100644
index 000000000..2fbe55b51
--- /dev/null
+++ b/changelog/991.bugfix.rst
@@ -0,0 +1 @@
+Fixed a memory leak when deep-copying an `NDCube` object or its coordinates by properly implementing `__deepcopy__` for `ExtraCoords` and `GlobalCoords`.
diff --git a/ndcube/extra_coords/extra_coords.py b/ndcube/extra_coords/extra_coords.py
index c5450a18a..c78dd448c 100644
--- a/ndcube/extra_coords/extra_coords.py
+++ b/ndcube/extra_coords/extra_coords.py
@@ -1,4 +1,5 @@
 import abc
+import copy
 from collections.abc import Iterable
 from functools import partial, reduce
 from numbers import Integral
@@ -156,7 +157,7 @@ def __init__(self, ndcube=None):
         self._ndcube = ndcube
 
     def __deepcopy__(self, memo):
-        import copy
+
         cls = self.__class__
         result = cls.__new__(cls)
         memo[id(self)] = result
diff --git a/ndcube/global_coords.py b/ndcube/global_coords.py
index fecc08057..bd564eb31 100644
--- a/ndcube/global_coords.py
+++ b/ndcube/global_coords.py
@@ -89,7 +89,7 @@ def __init__(self, ndcube=None):
         self._internal_coords = OrderedDict()
 
     def __deepcopy__(self, memo):
-        import copy
+
         cls = self.__class__
         result = cls.__new__(cls)
         memo[id(self)] = result

From 23694aae6531ae154381576243d268a0476aed28 Mon Sep 17 00:00:00 2001
From: Sumit Saraswat <sumitsaraswat@MacSam.local>
Date: Fri, 9 Oct 2026 11:22:19 +0530
Subject: [PATCH 3/3] docs: fix rst backticks in changelog

---
 changelog/991.bugfix.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/changelog/991.bugfix.rst b/changelog/991.bugfix.rst
index 2fbe55b51..3e21631ef 100644
--- a/changelog/991.bugfix.rst
+++ b/changelog/991.bugfix.rst
@@ -1 +1 @@
-Fixed a memory leak when deep-copying an `NDCube` object or its coordinates by properly implementing `__deepcopy__` for `ExtraCoords` and `GlobalCoords`.
+Fixed a memory leak when deep-copying an ``NDCube`` object or its coordinates by properly implementing ``__deepcopy__`` for ``ExtraCoords`` and ``GlobalCoords``.