Check pointer before dereferencing

Fixes crash on selecting and cutting/copying in a new document. Not
every paint device has a frameinterface.

BUG:457475

libs/image/kis_paint_device.cc

@@ -2207,7 +2207,10 @@ bool KisPaintDevice::burnKeyframe(int frameID)
 
 bool KisPaintDevice::burnKeyframe()
 {
-    return burnKeyframe(m_d->framesInterface->currentFrameId());
+    if (m_d->framesInterface) {
+        return burnKeyframe(m_d->framesInterface->currentFrameId());
+    }
+    return true;
 }
 
 /******************************************************************/

libs/ui/actions/kis_selection_action_factories.cpp

@@ -318,8 +318,9 @@ void KisCutCopyActionFactory::run(bool willCut, bool makeSharpClip, KisViewManag
 
         Q_FOREACH (KisNodeSP node, nodes) {
             KisLayerUtils::recursiveApplyNodes(node, [image, view, makeSharpClip] (KisNodeSP node) {
-                KisPaintDeviceSP dev = node->paintDevice();
-                dev->burnKeyframe();
+                if (node && node->paintDevice()) {
+                    node->paintDevice()->burnKeyframe();
+                }
 
                 KisTimeSpan range;
 
@@ -329,8 +330,8 @@ void KisCutCopyActionFactory::run(bool willCut, bool makeSharpClip, KisViewManag
                     range = channel->affectedFrames(currentTime);
                 }
 
-                if (dev && !node->inherits("KisMask")) {
-                    ActionHelper::trimDevice(view, dev, makeSharpClip, range);
+                if (node && node->paintDevice() && !node->inherits("KisMask")) {
+                    ActionHelper::trimDevice(view, node->paintDevice(), makeSharpClip, range);
                 }
             });
         }

plugins/python/scripter/debugger_scripter/debugger.py

@@ -89,9 +89,7 @@ class Debugger(bdb.Bdb):
 
         while True:
             if self.applicationq.empty():
-                # 'yield from' is not available in Python 2.
-                for i in asyncio.sleep(0.3):
-                    yield i
+                yield from asyncio.sleep(0.3)
             else:
                 while not self.applicationq.empty():
                     self.application_data.update(self.applicationq.get())