From: Zephaniah E. Loss-Cutler-Hull <warp@aehallh.com>
Date: Sat, 15 Aug 2020 10:23:27 +0000 (-0700)
Subject: unlockDialog: Defend against absence of blur effect
X-Git-Tag: archive/raspbian/50.5-1+rpi1~1^2~684^2^2~2
X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/%22/%22http:/www.example.com/cgi/%22?a=commitdiff_plain;h=093603b35e085ffa88c49bae6a35fd93ce856e4d;p=gnome-shell.git

unlockDialog: Defend against absence of blur effect

widget.get_effect(...) can return null while locking the screen, resulting
in a TypeError. In this situation the screen ends up black with a cursor
but never going to sleep, and moving the mouse brings the old screen
contents up but does not allow unlocking.

unlockDialog.js assumes that widget.get_effect will return non-null,
but other places such as getWindowDimmer in windowManager.js go out of
their way to be more careful.

[smcv: Add commit message, remove hard tabs, add missing semicolon]

Resolves: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/3071
Bug-Debian: https://bugs.debian.org/968440
---

diff --git a/js/ui/unlockDialog.js b/js/ui/unlockDialog.js
index aea7b6004..4f461f398 100644
--- a/js/ui/unlockDialog.js
+++ b/js/ui/unlockDialog.js
@@ -647,10 +647,14 @@ var UnlockDialog = GObject.registerClass({
         const themeContext = St.ThemeContext.get_for_stage(global.stage);
 
         for (const widget of this._backgroundGroup) {
-            widget.get_effect('blur').set({
-                brightness: BLUR_BRIGHTNESS,
-                sigma: BLUR_SIGMA * themeContext.scale_factor,
-            });
+            const effect = widget.get_effect('blur');
+
+            if (effect) {
+                effect.set({
+                    brightness: BLUR_BRIGHTNESS,
+                    sigma: BLUR_SIGMA * themeContext.scale_factor,
+                });
+            }
         }
     }