Do not trigger slicing if there's no slicable object

CURA-6604

1 files changed, 13 insertions, 0 deletions

diff --git a/plugins/CuraEngineBackend/CuraEngineBackend.py b/plugins/CuraEngineBackend/CuraEngineBackend.py
index 994966f9b7..ddf7864bb3 100755
--- a/plugins/CuraEngineBackend/CuraEngineBackend.py
+++ b/plugins/CuraEngineBackend/CuraEngineBackend.py
@@ -543,6 +543,15 @@ class CuraEngineBackend(QObject, Backend):
         if error.getErrorCode() == Arcus.ErrorCode.BindFailedError and self._start_slice_job is not None:
             self._start_slice_job.setIsCancelled(False)
 
+    # Check if there's any slicable object in the scene.
+    def hasSlicableObject(self) -> bool:
+        has_slicable = False
+        for node in DepthFirstIterator(self._scene.getRoot()):
+            if node.callDecoration("isSliceable"):
+                has_slicable = True
+                break
+        return has_slicable
+
     ##  Remove old layer data (if any)
     def _clearLayerData(self, build_plate_numbers: Set = None) -> None:
         # Clear out any old gcode
@@ -561,6 +570,10 @@ class CuraEngineBackend(QObject, Backend):
 
     ##  Convenient function: mark everything to slice, emit state and clear layer data
     def needsSlicing(self) -> None:
+        # CURA-6604: If there's no slicable object, do not (try to) trigger slice, which will clear all the current
+        # gcode. This can break Gcode file loading if it tries to remove it afterwards.
+        if not self.hasSlicableObject():
+            return
         self.determineAutoSlicing()
         self.stopSlicing()
         self.markSliceAll()