FIX: Disallow twinx/twiny on Axes3D

timhoffm · timhoffm · commit bc263898d072 · 2026-04-18T10:28:06.000+02:00
Closes matplotlib#31522. The root cause is that Axes3D inherits a lot of functionality from Axes that does not work for 3D. This is a design flaw we cannot easily fix. With this PR we have at least a reasonable mechanism in place to flag not-supported methods. When we get aware of additional methods, we can easily add them.
diff --git a/lib/mpl_toolkits/mplot3d/axes3d.py b/lib/mpl_toolkits/mplot3d/axes3d.py
@@ -71,6 +71,11 @@ class Axes3D(Axes):
         As a user, you do not instantiate Axes directly, but use Axes creation
         methods instead; e.g. from `.pyplot` or `.Figure`:
         `~.pyplot.subplots`, `~.pyplot.subplot_mosaic` or `.Figure.add_axes`.
+
+    .. note::
+
+        Some of the inherited behavior of Axes is not applicable to 3d and will raise
+        a `NotImplementedError`.
     """
     name = '3d'
 
@@ -1197,10 +1202,18 @@ def set_zscale(self, value, **kwargs):
         """
         self._set_axis_scale(self.zaxis, value, **kwargs)
 
+    def _raise_not_implemented(self, name, *args, **kwargs):
+        raise NotImplementedError(f"Axes3D does not support '{name}'.")
+
+    twinx = partialmethod(_raise_not_implemented, "twinx")
+    twiny = partialmethod(_raise_not_implemented, "twiny")
+    secondary_xaxis = partialmethod(_raise_not_implemented, "secondary_xaxis")
+    secondary_yaxis = partialmethod(_raise_not_implemented, "secondary_yaxis")
+
     def _raise_semilog_not_implemented(self, name, *args, **kwargs):
         raise NotImplementedError(
-            f"Axes3D does not support {name}. Use ax.set_xscale/set_yscale/set_zscale "
-            "and ax.plot(...) instead."
+            f"Axes3D does not support '{name}'. "
+            "Use ax.set_xscale/set_yscale/set_zscale and ax.plot(...) instead."
         )
 
     semilogx = partialmethod(_raise_semilog_not_implemented, "semilogx")
