Trying to start deckmaster with no active window panics

[rubiojr]

I don't know much about xorg, but it doesn't happen once you touch the background with the mouse (making the background the first "active window" I guess?), i.e. right after a fresh start in my raspi with the default desktop:

panic: runtime error: index out of range [0] with length 0                                                                                                                                                           
                                                                                                                                                                                                                     
goroutine 1 [running]:                                                                                                                                                                                               
github.com/BurntSushi/xgb.Get32(...)                                                                                                                                                                                 
        /home/rubiojr/go/pkg/mod/github.com/!burnt!sushi/[email protected]/help.go:87                                                                                                           
main.Xorg.active(0x2062af0, 0x20803c0, 0x389, 0x21b1540, 0x21b1550, 0x21b1570, 0x21b1590, 0x0, 0x0, 0x0, ...)                                                                                                        
        /home/rubiojr/git/muesli/deckmaster/desktop_unix.go:173 +0x108                                                                                                                                               
main.Xorg.window(0x2062af0, 0x20803c0, 0x389, 0x21b1540, 0x21b1550, 0x21b1570, 0x21b1590, 0x0, 0x0, 0x0, ...)                                                                                                        
        /home/rubiojr/git/muesli/deckmaster/desktop_unix.go:219 +0x30                                                                                                                                                
main.(*Xorg).TrackWindows(0x40f708, 0x219ccc0, 0x3b9aca00, 0x0)                                                                                                                                                      
        /home/rubiojr/git/muesli/deckmaster/desktop_unix.go:92 +0x34                                                                                                                                                 
main.main()                                                                                                                                                                                                          
        /home/rubiojr/git/muesli/deckmaster/main.go:85 +0x1cc                                                                                                                                                        

This is the workaround I'm using, no idea how to correctly solve it unfortunately:

diff --git a/desktop_unix.go b/desktop_unix.go
index b30a702..b8987f1 100644
--- a/desktop_unix.go
+++ b/desktop_unix.go
@@ -170,6 +170,9 @@ func (x Xorg) active() xproto.Window {
        if err != nil {
                return x.root
        }
+       if len(p.Value) == 0 {
+               return 0
+       }
        return xproto.Window(xgb.Get32(p.Value))
 }