Fix: properly decouple from pyplot and specific backends when destroying

timhoffm · timhoffm · commit d0958e4229bb · 2025-07-27T23:32:44.000+02:00
When destroying a manager, replace the figure's canvas by a
figure canvas base.
diff --git a/lib/matplotlib/backends/backend_qt.py b/lib/matplotlib/backends/backend_qt.py
@@ -664,6 +664,7 @@ def show(self):
             self.window.raise_()
 
     def destroy(self, *args):
+        self.canvas.figure._set_base_canvas()
         # check for qApp first, as PySide deletes it in its atexit handler
         if QtWidgets.QApplication.instance() is None:
             return
diff --git a/lib/matplotlib/figure.py b/lib/matplotlib/figure.py
@@ -2642,7 +2642,7 @@ def __init__(self,
         self._set_artist_props(self.patch)
         self.patch.set_antialiased(False)
 
-        FigureCanvasBase(self)  # Set self.canvas.
+        self._set_base_canvas()
 
         if subplotpars is None:
             subplotpars = SubplotParams()
@@ -2996,6 +2996,15 @@ def get_constrained_layout_pads(self, relative=False):
 
         return w_pad, h_pad, wspace, hspace
 
+    def _set_base_canvas(self):
+        """
+        Initialize self.canvas with a FigureCanvasBase instance.
+
+        This is used upon initialization of the Figure, but also
+        to reset the canvas when decoupling from pyplot.
+        """
+        FigureCanvasBase(self)  # Set self.canvas as a side-effect
+
     def set_canvas(self, canvas):
         """
         Set the canvas that contains the figure
