Outliner/layer: fix users trying to drop a collection into itself (recursion hell)

source/blender/blenkernel/intern/layer.c

@@ -580,6 +580,11 @@ bool BKE_layer_collection_move_into(const Scene *scene, LayerCollection *lc_dst,
 		return false;
 	}
 
+	/* We can't nest the collection into itself */
+	if (lc_src->scene_collection == lc_dst->scene_collection) {
+		return false;
+	}
+
 	/* Collection is already where we wanted it to be */
 	if (lc_dst->layer_collections.last == lc_src) {
 		return false;

tests/python/render_layer/CMakeLists.txt

@@ -135,6 +135,7 @@ RENDER_LAYER_TEST(move_into_layer_collection_f)
 RENDER_LAYER_TEST(move_into_layer_collection_g)
 RENDER_LAYER_TEST(move_into_layer_collection_h)
 RENDER_LAYER_TEST(move_into_layer_collection_i)
+RENDER_LAYER_TEST(move_into_layer_collection_j)
 RENDER_LAYER_TEST(layer_linking)
 RENDER_LAYER_TEST(layer_syncinc)
 RENDER_LAYER_TEST(scene_copy)

tests/python/render_layer/test_move_into_layer_collection_j.py

@@ -0,0 +1,49 @@
+# ./blender.bin --background -noaudio --python tests/python/render_layer/test_link.py -- --testdir="/data/lib/tests/"
+
+# ############################################################
+# Importing - Same For All Render Layer Tests
+# ############################################################
+
+import unittest
+
+import os, sys
+sys.path.append(os.path.dirname(__file__))
+
+from render_layer_common import *
+
+
+# ############################################################
+# Testing
+# ############################################################
+
+class UnitTesting(MoveLayerCollectionTesting):
+    def get_reference_scene_tree_map(self):
+        # original tree, no changes
+        return self.get_initial_scene_tree_map()
+
+    def get_reference_layers_tree_map(self):
+        # original tree, no changes
+        return self.get_initial_layers_tree_map()
+
+    def test_layer_collection_into(self):
+        """
+        Test outliner operations
+        Prevent collection from being dragged into itself
+        """
+        self.setup_tree()
+        self.assertFalse(self.move_into("Layer 2.dog", "Layer 2.3.dog"))
+        self.compare_tree_maps()
+
+
+# ############################################################
+# Main - Same For All Render Layer Tests
+# ############################################################
+
+if __name__ == '__main__':
+    import sys
+
+    extra_arguments = sys.argv[sys.argv.index("--") + 1:] if "--" in sys.argv else []
+    sys.argv = [__file__] + (sys.argv[sys.argv.index("--") + 2:] if "--" in sys.argv else [])
+
+    UnitTesting._extra_arguments = extra_arguments
+    unittest.main()