Fix crash in early window raise in gtk3.

anntzer · anntzer · commit 0e4cd8898af1 · 2021-03-09T11:37:50.000+01:00
Repro:

    import matplotlib as mpl
    import matplotlib.pyplot as plt
    mpl.use('GTK3Agg')
    plt.figure().canvas.mpl_connect('resize_event', lambda e: plt.pause(1))
    plt.show()
diff --git a/lib/matplotlib/backends/backend_gtk3.py b/lib/matplotlib/backends/backend_gtk3.py
@@ -391,7 +391,11 @@ def show(self):
         # show the figure window
         self.window.show()
         self.canvas.draw()
-        if mpl.rcParams['figure.raise_window']:
+        # If this is called by a callback early during init, self.window (a
+        # GtkWindow) may not have an associated low-level GdkWindow
+        # (self.window.get_window()) yet, and present() would crash -- hence
+        # the additional check.
+        if mpl.rcParams['figure.raise_window'] and self.window.get_window():
             self.window.present()
 
     def full_screen_toggle(self):
