Anim: add checks for system overrides to bone collection operators

Editability checks shouldn't just check for linked data & library
overrides, but also for the type of library override. A "system
override" should still not be editable by users.

This fixes #115310: Bone collections can be added to system-overridden
(i.e. non-user-editable) armatures

source/blender/animrig/intern/bone_collections.cc

@@ -26,6 +26,7 @@
 #include "BKE_animsys.h"
 #include "BKE_idprop.h"
 #include "BKE_lib_id.h"
+#include "BKE_lib_override.hh"
 
 #include "ANIM_armature_iter.hh"
 #include "ANIM_bone_collections.hh"
@@ -287,7 +288,14 @@ bool ANIM_armature_bonecoll_is_editable(const bArmature *armature, const BoneCol
   if (ID_IS_LINKED(armature) && !is_override) {
     return false;
   }
+
+  if (is_override && BKE_lib_override_library_is_system_defined(nullptr, &armature->id)) {
+    /* A system override is still not editable. */
+    return false;
+  }
+
   if (is_override && (bcoll->flags & BONE_COLLECTION_OVERRIDE_LIBRARY_LOCAL) == 0) {
+    /* This particular collection was not added in the local override, so not editable. */
     return false;
   }
   return true;

source/blender/editors/armature/bone_collections.cc

@@ -17,6 +17,7 @@
 #include "BKE_action.h"
 #include "BKE_context.hh"
 #include "BKE_layer.h"
+#include "BKE_lib_override.hh"
 #include "BKE_report.h"
 
 #include "BLT_translation.h"
@@ -63,6 +64,13 @@ static bool bone_collection_add_poll(bContext *C)
     return false;
   }
 
+  if (BKE_lib_override_library_is_system_defined(nullptr, reinterpret_cast<ID *>(ob->data))) {
+    CTX_wm_operator_poll_msg_set(C,
+                                 "Cannot add bone collections to a linked Armature with a system "
+                                 "override; explicitly create an override on the Armature");
+    return false;
+  }
+
   return true;
 }
 
@@ -80,8 +88,14 @@ static bool active_bone_collection_poll(bContext *C)
   }
 
   bArmature *armature = static_cast<bArmature *>(ob->data);
-  BoneCollection *bcoll = armature->runtime.active_collection;
+  if (BKE_lib_override_library_is_system_defined(nullptr, &armature->id)) {
+    CTX_wm_operator_poll_msg_set(C,
+                                 "Cannot update a linked Armature with a system override; "
+                                 "explicitly create an override on the Armature");
+    return false;
+  }
 
+  BoneCollection *bcoll = armature->runtime.active_collection;
   if (bcoll == nullptr) {
     CTX_wm_operator_poll_msg_set(C, "Armature has no active bone collection, select one first");
     return false;
@@ -387,6 +401,12 @@ static bool bone_collection_assign_poll(bContext *C)
         C, "Cannot edit bone collections on linked Armatures without override");
     return false;
   }
+  if (BKE_lib_override_library_is_system_defined(nullptr, &armature->id)) {
+    CTX_wm_operator_poll_msg_set(C,
+                                 "Cannot edit bone collections on a linked Armature with a system "
+                                 "override; explicitly create an override on the Armature");
+    return false;
+  }
 
   /* The target bone collection can be specified by name in an operator property, but that's not
    * available here. So just allow in the poll function, and do the final check in the execute. */
@@ -484,6 +504,12 @@ static bool bone_collection_create_and_assign_poll(bContext *C)
         C, "Cannot edit bone collections on linked Armatures without override");
     return false;
   }
+  if (BKE_lib_override_library_is_system_defined(nullptr, &armature->id)) {
+    CTX_wm_operator_poll_msg_set(C,
+                                 "Cannot edit bone collections on a linked Armature with a system "
+                                 "override; explicitly create an override on the Armature");
+    return false;
+  }
 
   return true;
 }
@@ -951,11 +977,19 @@ static bool move_to_collection_poll(bContext *C)
     return false;
   }
 
-  if (ID_IS_LINKED(ob->data) && !ID_IS_OVERRIDE_LIBRARY(ob->data)) {
+  const bArmature *armature = static_cast<bArmature *>(ob->data);
+  if (ID_IS_LINKED(armature) && !ID_IS_OVERRIDE_LIBRARY(armature)) {
     CTX_wm_operator_poll_msg_set(C, "This needs a local Armature or an override");
     return false;
   }
 
+  if (BKE_lib_override_library_is_system_defined(nullptr, &armature->id)) {
+    CTX_wm_operator_poll_msg_set(C,
+                                 "Cannot update a linked Armature with a system override; "
+                                 "explicitly create an override on the Armature");
+    return false;
+  }
+
   /* Ideally this would also check the target bone collection to move/assign to.
    * However, that requires access to the operator properties, and those are not
    * available in the poll function. */