From 14711fac10f959162a054b2b3eb43fa3ef742d49 Mon Sep 17 00:00:00 2001
From: Thomas A Caswell <tcaswell@gmail.com>
Date: Wed, 26 Jun 2024 11:43:43 -0400
Subject: [PATCH] Backport PR #28465: Fix pickling of SubFigures

---
 lib/matplotlib/figure.py            | 5 ++++-
 lib/matplotlib/figure.pyi           | 3 ++-
 lib/matplotlib/tests/test_pickle.py | 5 +++++
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/lib/matplotlib/figure.py b/lib/matplotlib/figure.py
index e5f4bb9421cf..d75ff527a008 100644
--- a/lib/matplotlib/figure.py
+++ b/lib/matplotlib/figure.py
@@ -2224,7 +2224,6 @@ def __init__(self, parent, subplotspec, *,
         self.subplotpars = parent.subplotpars
         self.dpi_scale_trans = parent.dpi_scale_trans
         self._axobservers = parent._axobservers
-        self.canvas = parent.canvas
         self.transFigure = parent.transFigure
         self.bbox_relative = Bbox.null()
         self._redo_transform_rel_fig()
@@ -2241,6 +2240,10 @@ def __init__(self, parent, subplotspec, *,
         self._set_artist_props(self.patch)
         self.patch.set_antialiased(False)
 
+    @property
+    def canvas(self):
+        return self._parent.canvas
+
     @property
     def dpi(self):
         return self._parent.dpi
diff --git a/lib/matplotlib/figure.pyi b/lib/matplotlib/figure.pyi
index 21de9159d56c..b079312695c1 100644
--- a/lib/matplotlib/figure.pyi
+++ b/lib/matplotlib/figure.pyi
@@ -263,7 +263,6 @@ class SubFigure(FigureBase):
     figure: Figure
     subplotpars: SubplotParams
     dpi_scale_trans: Affine2D
-    canvas: FigureCanvasBase
     transFigure: Transform
     bbox_relative: Bbox
     figbbox: BboxBase
@@ -282,6 +281,8 @@ class SubFigure(FigureBase):
         **kwargs
     ) -> None: ...
     @property
+    def canvas(self) -> FigureCanvasBase: ...
+    @property
     def dpi(self) -> float: ...
     @dpi.setter
     def dpi(self, value: float) -> None: ...
diff --git a/lib/matplotlib/tests/test_pickle.py b/lib/matplotlib/tests/test_pickle.py
index 7e7ccc14bf8f..0cba4f392035 100644
--- a/lib/matplotlib/tests/test_pickle.py
+++ b/lib/matplotlib/tests/test_pickle.py
@@ -93,6 +93,11 @@ def _generate_complete_test_figure(fig_ref):
     plt.errorbar(x, x * -0.5, xerr=0.2, yerr=0.4, label='$-.5 x$')
     plt.legend(draggable=True)
 
+    # Ensure subfigure parenting works.
+    subfigs = fig_ref.subfigures(2)
+    subfigs[0].subplots(1, 2)
+    subfigs[1].subplots(1, 2)
+
     fig_ref.align_ylabels()  # Test handling of _align_label_groups Groupers.