Backport PR matplotlib#18173: Fix the return value of Axes.get_naviga…

…te_mode.

lib/matplotlib/backend_bases.py

@@ -2777,6 +2777,10 @@ class _Mode(str, Enum):
     def __str__(self):
         return self.value
 
+    @property
+    def _navigate_mode(self):
+        return self.name if self is not _Mode.NONE else None
+
 
 class NavigationToolbar2:
     """
@@ -3035,7 +3039,7 @@ def pan(self, *args):
             self.mode = _Mode.PAN
             self.canvas.widgetlock(self)
         for a in self.canvas.figure.get_axes():
-            a.set_navigate_mode(self.mode)
+            a.set_navigate_mode(self.mode._navigate_mode)
         self.set_message(self.mode)
 
     def press_pan(self, event):
@@ -3105,7 +3109,7 @@ def zoom(self, *args):
             self.mode = _Mode.ZOOM
             self.canvas.widgetlock(self)
         for a in self.canvas.figure.get_axes():
-            a.set_navigate_mode(self.mode)
+            a.set_navigate_mode(self.mode._navigate_mode)
         self.set_message(self.mode)
 
     def press_zoom(self, event):

lib/matplotlib/tests/test_backend_bases.py

@@ -107,9 +107,11 @@ def test_location_event_position(x, y):
 def test_interactive_zoom():
     fig, ax = plt.subplots()
     ax.set(xscale="logit")
+    assert ax.get_navigate_mode() is None
 
     tb = NavigationToolbar2(fig.canvas)
     tb.zoom()
+    assert ax.get_navigate_mode() == 'ZOOM'
 
     xlim0 = ax.get_xlim()
     ylim0 = ax.get_ylim()
@@ -143,3 +145,6 @@ def test_interactive_zoom():
     # Absolute tolerance much less than original xmin (1e-7).
     assert ax.get_xlim() == pytest.approx(xlim0, rel=0, abs=1e-10)
     assert ax.get_ylim() == pytest.approx(ylim0, rel=0, abs=1e-10)
+
+    tb.zoom()
+    assert ax.get_navigate_mode() is None