glTF exporter: add check when armature animation is binded to mesh object

io_scene_gltf2/__init__.py

@@ -15,7 +15,7 @@
 bl_info = {
     'name': 'glTF 2.0 format',
     'author': 'Julien Duroure, Norbert Nopper, Urs Hanselmann, Moritz Becher, Benjamin Schmithüsen, Jim Eckerlein, and many external contributors',
-    "version": (1, 3, 19),
+    "version": (1, 3, 20),
     'blender': (2, 90, 0),
     'location': 'File > Import-Export',
     'description': 'Import-Export as glTF 2.0',

io_scene_gltf2/blender/exp/gltf2_blender_gather_animation_channels.py

@@ -173,6 +173,9 @@ def __get_channel_group_sorted(channels: typing.Tuple[bpy.types.FCurve], blender
                 else:
                     all_sorted_channels.append(existing_idx[i])
 
+            if all([i is None for i in all_sorted_channels]): # all channel in error, and some non keyed SK
+                return channels             # This happen when an armature action is linked to a mesh object with non keyed SK
+
             return tuple(all_sorted_channels)
 
     # if not shapekeys, stay in same order, because order doesn't matter