Merge pull request #20967 from meeseeksmachine/auto-backport-of-pr-20965-on-v3.5.x

dstansby · web-flow · commit 4cf1bb7bc4e1 · 2021-09-01T23:01:38.000+01:00
Backport PR #20965 on branch v3.5.x (BUG: Fix f_back is None handling)
diff --git a/lib/matplotlib/backends/backend_qt.py b/lib/matplotlib/backends/backend_qt.py
@@ -333,7 +333,8 @@ def keyReleaseEvent(self, event):
 
     def resizeEvent(self, event):
         frame = sys._getframe()
-        if frame.f_code is frame.f_back.f_code:  # Prevent PyQt6 recursion.
+        # Prevent PyQt6 recursion, but sometimes frame.f_back is None
+        if frame.f_code is getattr(frame.f_back, 'f_code', None):
             return
         w = event.size().width() * self.device_pixel_ratio
         h = event.size().height() * self.device_pixel_ratio
