Fernschreiber X

When using Debian sid, compiling, and then starting Fernschreiber X, I get error:

2020/01/14 11:51:22 <iq xml:lang='fi' to='xet7@guelker.eu/fernschreiberx' from='xet7@guelker.eu' type='result' id='47690vkkbrwzu33060221239'><query xmlns='jabber:iq:roster'><item subscription='both' jid='mg@guelker.eu'/><item subscription='both' jid='sydney@sydev.us'/><item ask='subscribe' jid='sydney@kode.im'/></query></iq>
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x30 pc=0xa24c16]

goroutine 1 [running]:
main.(*CapsEntry).HasFeature(0x0, 0xbe6ebd, 0x12, 0x5)
    /home/user/go/src/mg.guelker.eu/fernschreiberx/fernschreiberx/caps_cache.go:182 +0x26
main.(*Application).onFeaturesList.func1.1(0xaee700, 0xc000264a40)
    /home/user/go/src/mg.guelker.eu/fernschreiberx/fernschreiberx/application.go:357 +0x142
main.(*Application).onIQStanza(0xc0000ee9c0)
    /home/user/go/src/mg.guelker.eu/fernschreiberx/fernschreiberx/application.go:644 +0xe2a
main.NewApplication.func11()
    /home/user/go/src/mg.guelker.eu/fernschreiberx/fernschreiberx/application.go:76 +0x2a
reflect.Value.call(0xab7d00, 0xc000021e30, 0x13, 0xbe1685, 0x4, 0x13ec1e8, 0x0, 0x0, 0xc000170ac8, 0x4af0ac, ...)
    /usr/lib/go-1.13/src/reflect/value.go:460 +0x5f6
reflect.Value.Call(0xab7d00, 0xc000021e30, 0x13, 0x13ec1e8, 0x0, 0x0, 0x0, 0x0, 0x0)
    /usr/lib/go-1.13/src/reflect/value.go:321 +0xb4
github.com/gotk3/gotk3/glib.goMarshal(0x1e23dc0, 0x2343a80, 0xc000000001, 0x229eed0, 0x7ffc778182d0, 0x0)
    /home/user/go/src/github.com/gotk3/gotk3/glib/glib.go:233 +0x700
github.com/gotk3/gotk3/glib._cgoexpwrap_25d77dd69e85_goMarshal(0x1e23dc0, 0x2343a80, 0xa00000001, 0x229eed0, 0x7ffc778182d0, 0x0)
    _cgo_gotypes.go:4413 +0x5b
github.com/gotk3/gotk3/glib._Cfunc_g_signal_emitv(0x229eed0, 0x18, 0x2343a80)
    _cgo_gotypes.go:3058 +0x45
github.com/gotk3/gotk3/glib.(*Object).Emit(0xc0000105e0, 0xbe5466, 0xe, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0)
    /home/user/go/src/github.com/gotk3/gotk3/glib/glib.go:818 +0x486
main.emitXMPPSignal(0xbe5466, 0xe)
    /home/user/go/src/mg.guelker.eu/fernschreiberx/fernschreiberx/transformer.go:94 +0x58
reflect.Value.call(0xac0040, 0xc01d10, 0x13, 0xbe1685, 0x4, 0xc0002d7840, 0x1, 0x1, 0x98, 0x4af0ac, ...)
    /usr/lib/go-1.13/src/reflect/value.go:460 +0x5f6
reflect.Value.Call(0xac0040, 0xc01d10, 0x13, 0xc0002d7840, 0x1, 0x1, 0xc0002d4ef0, 0x98, 0x0)
    /usr/lib/go-1.13/src/reflect/value.go:321 +0xb4
github.com/gotk3/gotk3/glib.goMarshal(0x7f11800058d0, 0x7ffc77818600, 0xc000000000, 0x0, 0x0, 0x0)
    /home/user/go/src/github.com/gotk3/gotk3/glib/glib.go:233 +0x700
github.com/gotk3/gotk3/glib._cgoexpwrap_25d77dd69e85_goMarshal(0x7f11800058d0, 0x7ffc77818600, 0x0, 0x0, 0x0, 0x0)
    _cgo_gotypes.go:4413 +0x5b
github.com/gotk3/gotk3/gtk._Cfunc_gtk_main()
    _cgo_gotypes.go:14719 +0x41
github.com/gotk3/gotk3/gtk.Main(...)
    /home/user/go/src/github.com/gotk3/gotk3/gtk/gtk.go:987
main.(*Application).onActivate(0xc0000ee9c0)
    /home/user/go/src/mg.guelker.eu/fernschreiberx/fernschreiberx/application.go:228 +0x1c9
main.NewApplication.func2()
    /home/user/go/src/mg.guelker.eu/fernschreiberx/fernschreiberx/application.go:66 +0x2a
reflect.Value.call(0xab7d00, 0xc000021d10, 0x13, 0xbe1685, 0x4, 0x13ec1e8, 0x0, 0x0, 0xc0000bba18, 0x4af0ac, ...)
    /usr/lib/go-1.13/src/reflect/value.go:460 +0x5f6
reflect.Value.Call(0xab7d00, 0xc000021d10, 0x13, 0x13ec1e8, 0x0, 0x0, 0x0, 0x0, 0x0)
    /usr/lib/go-1.13/src/reflect/value.go:321 +0xb4
github.com/gotk3/gotk3/glib.goMarshal(0x1e22be0, 0x0, 0x1, 0x7ffc77818ac0, 0x7ffc77818a40, 0x0)
    /home/user/go/src/github.com/gotk3/gotk3/glib/glib.go:233 +0x700
github.com/gotk3/gotk3/glib._cgoexpwrap_25d77dd69e85_goMarshal(0x1e22be0, 0x0, 0x1, 0x7ffc77818ac0, 0x7ffc77818a40, 0x0)
    _cgo_gotypes.go:4413 +0x5b
github.com/gotk3/gotk3/glib._Cfunc_g_application_run(0x1e1f0f0, 0x1, 0x1e20880, 0x0)
    _cgo_gotypes.go:1236 +0x4d
github.com/gotk3/gotk3/glib.(*Application).Run.func4(0xc000093b90, 0xc0000201b0, 0x1, 0x1, 0x1e20880, 0xc0000105e0)
    /home/user/go/src/github.com/gotk3/gotk3/glib/application.go:202 +0xa6
github.com/gotk3/gotk3/glib.(*Application).Run(0xc000093b90, 0xc0000201b0, 0x1, 0x1, 0x0)
    /home/user/go/src/github.com/gotk3/gotk3/glib/application.go:202 +0x181
main.(*Application).Run(...)
    /home/user/go/src/mg.guelker.eu/fernschreiberx/fernschreiberx/application.go:106
main.main()
    /home/user/go/src/mg.guelker.eu/fernschreiberx/fernschreiberx/main.go:40 +0x86

But if I comment out this code:

diff --git a/fernschreiberx/caps_cache.go b/fernschreiberx/caps_cache.go
index 322e233..9e00315 100644
--- a/fernschreiberx/caps_cache.go
+++ b/fernschreiberx/caps_cache.go
@@ -179,11 +179,11 @@ func (recv *CapabilitiesCache) Load() error {
 // which needs to be a URI. Returns true if the feature is found,
 // false otherwise.
 func (recv *CapsEntry) HasFeature(feature string) bool {
-       for _, f := range recv.Features {
-               if f == feature {
-                       return true
-               }
-       }
+       //for _, f := range recv.Features {
+       //      if f == feature {
+       //              return true
+       //      }
+       //}

        return false
 }

Then I can start Fernschreiber X successfully.