From dd286f93eb896b60ceeac556c7524b2e982aa207 Mon Sep 17 00:00:00 2001
From: Philippe Crassous <philippe.crassous@ubisoft.com>
Date: Wed, 28 Apr 2021 20:31:49 +0200
Subject: [PATCH] fix: tag for update after updating an array

- after receiving a strokes update, the receiver
display was not updated until edit mode was entered
---
 mixer/blender_client/data.py          | 16 ++++++++++++++--
 mixer/blender_data/bpy_data_proxy.py  | 11 ++++++++---
 mixer/blender_data/datablock_proxy.py | 13 ++++++++++---
 3 files changed, 32 insertions(+), 8 deletions(-)

diff --git a/mixer/blender_client/data.py b/mixer/blender_client/data.py
index ff1d546a..fbd34597 100644
--- a/mixer/blender_client/data.py
+++ b/mixer/blender_client/data.py
@@ -25,6 +25,8 @@
 import traceback
 from typing import List, TYPE_CHECKING
 
+import bpy
+
 from mixer.blender_data.json_codec import Codec, DecodeError, EncodeError
 from mixer.blender_data.messages import (
     BlenderDataMessage,
@@ -145,14 +147,24 @@ def build_data_create(buffer):
 
 
 def _build_soas(uuid: Uuid, soas: List[Soa]):
+    update = False
     try:
         for soa in soas:
-            share_data.bpy_data_proxy.update_soa(uuid, soa.path, soa.members)
+            update |= share_data.bpy_data_proxy.update_soa(uuid, soa.path, soa.members)
     except Exception:
+        # Partial update of arrays may cause data length mismatch between array elements (co, normals, ...)
         logger.error(f"Exception during update_soa for {uuid} {soa.path}")
+        logger.error(" -------  This may cause a Blender crash ---------")
         for line in traceback.format_exc().splitlines():
             logger.error(line)
-        logger.error("ignored")
+
+    if update:
+        # TODO this is skipped if the proxy update call is retained until returning into OBJECT mode
+        try:
+            # needed for Grease Pencil.
+            bpy.context.view_layer.update()
+        except Exception:
+            pass
 
 
 def build_data_update(buffer: bytes):
diff --git a/mixer/blender_data/bpy_data_proxy.py b/mixer/blender_data/bpy_data_proxy.py
index 90034054..be15f290 100644
--- a/mixer/blender_data/bpy_data_proxy.py
+++ b/mixer/blender_data/bpy_data_proxy.py
@@ -630,11 +630,16 @@ def diff(self, synchronized_properties: SynchronizedProperties) -> Optional[BpyD
             return diff
         return None
 
-    @retain(None)
-    def update_soa(self, uuid: Uuid, path: Path, soa_members: List[SoaMember]):
+    @retain(False)
+    def update_soa(self, uuid: Uuid, path: Path, soa_members: List[SoaMember]) -> bool:
+        """Update the arrays if the proxy identified by uuid.
+
+        Returns:
+            True if the view layer should be updated
+        """
         datablock_proxy = self.state.proxies[uuid]
         datablock = self.state.datablock(uuid)
-        datablock_proxy.update_soa(datablock, path, soa_members)
+        return datablock_proxy.update_soa(datablock, path, soa_members)
 
     def append_delayed_updates(self, delayed_updates: Set[T.ID]):
         self._delayed_local_updates |= {update.mixer_uuid for update in delayed_updates}
diff --git a/mixer/blender_data/datablock_proxy.py b/mixer/blender_data/datablock_proxy.py
index 232cd39b..6b1bf536 100644
--- a/mixer/blender_data/datablock_proxy.py
+++ b/mixer/blender_data/datablock_proxy.py
@@ -519,22 +519,29 @@ def apply_to_proxy(
         collection = getattr(bpy.data, self.collection_name)
         self.apply(attribute, collection, attribute.name, delta, context, to_blender=False)
 
-    def update_soa(self, bl_item, path: Path, soa_members: List[SoaMember]):
+    def update_soa(self, bl_item, path: Path, soa_members: List[SoaMember]) -> bool:
 
         r = self.find_by_path(bl_item, path)
         if r is None:
             logger.error(f"update_soa: {path} not found in {bl_item}")
-            return
+            return False
         container, container_proxy = r
         for soa_member in soa_members:
             soa_proxy = container_proxy.data(soa_member[0])
             soa_proxy.save_array(container, soa_member[0], soa_member[1])
 
-        # HACK force updates :
+        # HACK force updates : unsure what is strictly required
+        # specifying refresh is not compatible with Grease Pencil and causes a crash
+        update = False
         if isinstance(bl_item, T.Mesh):
             bl_item.update()
         elif isinstance(bl_item, T.Curve):
             bl_item.twist_mode = bl_item.twist_mode
+        elif isinstance(bl_item, T.GreasePencil):
+            bl_item.update_tag()
+            update = True
+
+        return update
 
     def diff(self, attribute: T.ID, key: Union[int, str], prop: T.Property, context: Context) -> Optional[Delta]:
         """