From 6a2af0741539316dded0189ddc1fca3bf9e3d236 Mon Sep 17 00:00:00 2001
From: Thomas A Caswell <tcaswell@gmail.com>
Date: Sun, 21 Nov 2021 18:58:41 -0500
Subject: [PATCH] FIX: deprecation of render keyword to do_3d_projection

Previously we both warned and required that renderer be an accepted argument.
---
 lib/mpl_toolkits/mplot3d/axes3d.py     | 15 +++++----
 lib/mpl_toolkits/tests/test_mplot3d.py | 46 ++++++++++++++++++++++++++
 2 files changed, 55 insertions(+), 6 deletions(-)

diff --git a/lib/mpl_toolkits/mplot3d/axes3d.py b/lib/mpl_toolkits/mplot3d/axes3d.py
index 605e0d8e8211..7c409cf2534f 100644
--- a/lib/mpl_toolkits/mplot3d/axes3d.py
+++ b/lib/mpl_toolkits/mplot3d/axes3d.py
@@ -428,12 +428,15 @@ def do_3d_projection(artist):
                     # deprecation has expired.
                     return artist.do_3d_projection()
 
-                _api.warn_deprecated(
-                    "3.4",
-                    message="The 'renderer' parameter of "
-                    "do_3d_projection() was deprecated in Matplotlib "
-                    "%(since)s and will be removed %(removal)s.")
-                return artist.do_3d_projection(renderer)
+                try:
+                    return artist.do_3d_projection()
+                except TypeError:
+                    _api.warn_deprecated(
+                        "3.4",
+                        message="The 'renderer' parameter of "
+                        "do_3d_projection() was deprecated in Matplotlib "
+                        "%(since)s and will be removed %(removal)s.")
+                    return artist.do_3d_projection(renderer)
 
             collections_and_patches = (
                 artist for artist in self._children
diff --git a/lib/mpl_toolkits/tests/test_mplot3d.py b/lib/mpl_toolkits/tests/test_mplot3d.py
index c3d107b40494..9d05acd86231 100644
--- a/lib/mpl_toolkits/tests/test_mplot3d.py
+++ b/lib/mpl_toolkits/tests/test_mplot3d.py
@@ -1711,3 +1711,49 @@ def test_view_init_vertical_axis(
         tickdir_expected = tickdirs_expected[i]
         tickdir_actual = axis._get_tickdir()
         np.testing.assert_array_equal(tickdir_expected, tickdir_actual)
+
+
+def test_do_3d_projection_renderer_deprecation_warn():
+    from matplotlib.patches import FancyArrowPatch
+    class Arrow3D(FancyArrowPatch):
+        def __init__(self, xs, ys, zs, *args, **kwargs):
+            super().__init__((0, 0), (0, 0), *args, **kwargs)
+            self._verts3d = xs, ys, zs
+
+        def do_3d_projection(self, render):
+            xs3d, ys3d, zs3d = self._verts3d
+            xs, ys, zs = proj3d.proj_transform(xs3d, ys3d, zs3d, self.axes.M)
+            self.set_positions((xs[0], ys[0]), (xs[1], ys[1]))
+
+            return np.min(zs)
+
+    fig = plt.figure()
+    ax = fig.add_subplot(111, projection='3d')
+    arrow_prop_dict = dict(mutation_scale=20, arrowstyle='-|>', color='k')
+    a = Arrow3D([0, 10], [0, 0], [0, 0], **arrow_prop_dict)
+    ax.add_artist(a)
+
+    with pytest.warns(MatplotlibDeprecationWarning):
+        fig.canvas.draw()
+
+
+def test_do_3d_projection_renderer_deprecation_nowarn():
+    from matplotlib.patches import FancyArrowPatch
+    class Arrow3D(FancyArrowPatch):
+        def __init__(self, xs, ys, zs, *args, **kwargs):
+            super().__init__((0, 0), (0, 0), *args, **kwargs)
+            self._verts3d = xs, ys, zs
+
+        def do_3d_projection(self):
+            xs3d, ys3d, zs3d = self._verts3d
+            xs, ys, zs = proj3d.proj_transform(xs3d, ys3d, zs3d, self.axes.M)
+            self.set_positions((xs[0], ys[0]), (xs[1], ys[1]))
+
+            return np.min(zs)
+
+    fig = plt.figure()
+    ax = fig.add_subplot(111, projection='3d')
+    arrow_prop_dict = dict(mutation_scale=20, arrowstyle='-|>', color='k')
+    a = Arrow3D([0, 10], [0, 0], [0, 0], **arrow_prop_dict)
+    ax.add_artist(a)
+    fig.canvas.draw()