Bugfix: Don’t crash when dock clients set the urgency hint (+testcase)

src/handlers.c

@@ -813,7 +813,11 @@ static int handle_hints(void *data, xcb_connection_t *conn, uint8_t state, xcb_w
     //CLIENT_LOG(con);
     LOG("Urgency flag changed to %d\n", con->urgent);
 
-    workspace_update_urgent_flag(con_get_workspace(con));
+    Con *ws;
+    /* Set the urgency flag on the workspace, if a workspace could be found
+     * (for dock clients, that is not the case). */
+    if ((ws = con_get_workspace(con)) != NULL)
+        workspace_update_urgent_flag(ws);
 
     tree_render();
 

testcases/t/62-regress-dock-urgent.t

@@ -0,0 +1,59 @@
+#!perl
+# vim:ts=4:sw=4:expandtab
+#
+# Regression test for setting the urgent hint on dock clients.
+# found in 4be3178d4d360c2996217d811e61161c84d25898
+#
+use X11::XCB qw(:all);
+use i3test;
+
+BEGIN {
+    use_ok('X11::XCB::Window');
+}
+
+my $x = X11::XCB::Connection->new;
+my $i3 = i3("/tmp/nestedcons");
+
+my $tmp = fresh_workspace;
+
+#####################################################################
+# verify that there is no dock window yet
+#####################################################################
+
+# Children of all dockareas
+my @docked = get_dock_clients;
+
+is(@docked, 0, 'no dock clients yet');
+
+# open a dock client
+
+my $window = $x->root->create_child(
+    class => WINDOW_CLASS_INPUT_OUTPUT,
+    rect => [ 0, 0, 30, 30],
+    background_color => '#FF0000',
+    window_type => $x->atom(name => '_NET_WM_WINDOW_TYPE_DOCK'),
+);
+
+$window->map;
+
+sleep 0.25;
+
+#####################################################################
+# check that we can find it in the layout tree at the expected position
+#####################################################################
+
+@docked = get_dock_clients;
+is(@docked, 1, 'one dock client found');
+
+# verify the height
+my $docknode = $docked[0];
+
+is($docknode->{rect}->{height}, 30, 'dock node has unchanged height');
+
+$window->add_hint('urgency');
+
+sleep 0.25;
+
+does_i3_live;
+
+done_testing;