From 7e6d1144824589c7a48899bcb615e6a03bc20215 Mon Sep 17 00:00:00 2001
From: MadPhysicist <jfoxrabinovitz@gmail.com>
Date: Tue, 11 Jun 2024 10:10:42 -0500
Subject: [PATCH 1/3] FIX: Made AffineDeltaTransform pass-through properly

---
 lib/matplotlib/transforms.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/lib/matplotlib/transforms.py b/lib/matplotlib/transforms.py
index 5003e2113930..e6e7a6bca637 100644
--- a/lib/matplotlib/transforms.py
+++ b/lib/matplotlib/transforms.py
@@ -2711,9 +2711,12 @@ class AffineDeltaTransform(Affine2DBase):
     This class is experimental as of 3.3, and the API may change.
     """
 
+    pass_through = True
+
     def __init__(self, transform, **kwargs):
         super().__init__(**kwargs)
         self._base_transform = transform
+        self.set_children(transform)
 
     __str__ = _make_str_method("_base_transform")
 

From d73bd6dee726b81efb73c630711319011e2b2689 Mon Sep 17 00:00:00 2001
From: MadPhysicist <jfoxrabinovitz@gmail.com>
Date: Tue, 11 Jun 2024 10:25:34 -0500
Subject: [PATCH 2/3] DOC: Added release note

---
 doc/api/next_api_changes/behavior/28375-MP.rst | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 doc/api/next_api_changes/behavior/28375-MP.rst

diff --git a/doc/api/next_api_changes/behavior/28375-MP.rst b/doc/api/next_api_changes/behavior/28375-MP.rst
new file mode 100644
index 000000000000..75d7f7cf5030
--- /dev/null
+++ b/doc/api/next_api_changes/behavior/28375-MP.rst
@@ -0,0 +1,5 @@
+``transforms.AffineDeltaTransform`` updates correctly on axis limit changes
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Before this change, transform sub-graphs with ``AffineDeltaTransform`` did not update correctly.
+This PR ensures that changes to the child transform are passed through correctly.

From 0b91d8ec999d89407285f83d9faab142cacbad6b Mon Sep 17 00:00:00 2001
From: MadPhysicist <jfoxrabinovitz@gmail.com>
Date: Tue, 11 Jun 2024 12:20:23 -0500
Subject: [PATCH 3/3] TST: Added a unit test to avoid CI problems

---
 lib/matplotlib/tests/test_transforms.py | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/lib/matplotlib/tests/test_transforms.py b/lib/matplotlib/tests/test_transforms.py
index 959814de82db..fb8b7d74bc94 100644
--- a/lib/matplotlib/tests/test_transforms.py
+++ b/lib/matplotlib/tests/test_transforms.py
@@ -341,6 +341,31 @@ def test_deepcopy(self):
         assert_array_equal(s.get_matrix(), a.get_matrix())
 
 
+class TestAffineDeltaTransform:
+    def test_invalidate(self):
+        before = np.array([[1.0, 4.0, 0.0],
+                           [5.0, 1.0, 0.0],
+                           [0.0, 0.0, 1.0]])
+        after = np.array([[1.0, 3.0, 0.0],
+                          [5.0, 1.0, 0.0],
+                          [0.0, 0.0, 1.0]])
+
+        # Translation and skew present
+        base = mtransforms.Affine2D.from_values(1, 5, 4, 1, 2, 3)
+        t = mtransforms.AffineDeltaTransform(base)
+        assert_array_equal(t.get_matrix(), before)
+
+        # Mess with the internal structure of `base` without invalidating
+        # This should not affect this transform because it's a passthrough:
+        # it's always invalid
+        base.get_matrix()[0, 1:] = 3
+        assert_array_equal(t.get_matrix(), after)
+
+        # Invalidate the base
+        base.invalidate()
+        assert_array_equal(t.get_matrix(), after)
+
+
 def test_non_affine_caching():
     class AssertingNonAffineTransform(mtransforms.Transform):
         """