From 4e5019e36f056766e818346c874bbfe7cd822a2a Mon Sep 17 00:00:00 2001
From: Oscar Gustafsson <oscar.gustafsson@gmail.com>
Date: Wed, 1 Jun 2022 12:30:25 +0200
Subject: [PATCH] Make sure SubFigure has _cachedRenderer

---
 lib/matplotlib/figure.py             |  8 ++++++++
 lib/matplotlib/tests/test_contour.py | 20 ++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/lib/matplotlib/figure.py b/lib/matplotlib/figure.py
index 0b8ad9828b3d..d0d9f8e695dc 100644
--- a/lib/matplotlib/figure.py
+++ b/lib/matplotlib/figure.py
@@ -2060,6 +2060,14 @@ def dpi(self):
     def dpi(self, value):
         self._parent.dpi = value
 
+    @property
+    def _cachedRenderer(self):
+        return self._parent._cachedRenderer
+
+    @_cachedRenderer.setter
+    def _cachedRenderer(self, renderer):
+        self._parent._cachedRenderer = renderer
+
     def _redo_transform_rel_fig(self, bbox=None):
         """
         Make the transSubfigure bbox relative to Figure transform.
diff --git a/lib/matplotlib/tests/test_contour.py b/lib/matplotlib/tests/test_contour.py
index bb7dd3630b97..5f3f961971e8 100644
--- a/lib/matplotlib/tests/test_contour.py
+++ b/lib/matplotlib/tests/test_contour.py
@@ -585,3 +585,23 @@ def test_all_algorithms():
         ax.contourf(x, y, z, algorithm=algorithm)
         ax.contour(x, y, z, algorithm=algorithm, colors='k')
         ax.set_title(algorithm)
+
+
+def test_subfigure_clabel():
+    # Smoke test for gh#23173
+    delta = 0.025
+    x = np.arange(-3.0, 3.0, delta)
+    y = np.arange(-2.0, 2.0, delta)
+    X, Y = np.meshgrid(x, y)
+    Z1 = np.exp(-(X**2) - Y**2)
+    Z2 = np.exp(-((X - 1) ** 2) - (Y - 1) ** 2)
+    Z = (Z1 - Z2) * 2
+
+    fig = plt.figure()
+    figs = fig.subfigures(nrows=1, ncols=2)
+
+    for f in figs:
+        ax = f.subplots()
+        CS = ax.contour(X, Y, Z)
+        ax.clabel(CS, inline=True, fontsize=10)
+        ax.set_title("Simplest default with labels")