LibOverride: Abstract a bit handling of local items of RNA collections.

RNA collections that support insertion of new items in liboverride
data-block need a special way to distiguish between locale and
orig-from-linked items (since some operations are allowed on the forer,
but no the latter).

In future we want a proper solution to abstract that at the
`BKE_lib_override` level, but for now we need to add some code for each
case.

Note that this commit also fixes a few potential issues with GPencil
modifiers, and constraints, regarding their handling of local overrides.

1 files changed, 13 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/modifier.c b/source/blender/blenkernel/intern/modifier.c
index c9bdaecfa2a..7865d44c446 100644
--- a/source/blender/blenkernel/intern/modifier.c
+++ b/source/blender/blenkernel/intern/modifier.c
@@ -574,6 +574,19 @@ bool BKE_modifier_is_enabled(const struct Scene *scene, ModifierData *md, int re
   return true;
 }
 
+/**
+ * Check whether given modifier is local when the object is a library override.
+ *
+ * \param md May be NULL, in which case we consider it as a non-local modifier case.
+ *
+ * \note This check is only valid for a liboverride data-block, it always return \a true otherwise.
+ */
+bool BKE_modifier_is_local_in_liboverride(const Object *ob, const ModifierData *md)
+{
+  return (!ID_IS_OVERRIDE_LIBRARY(ob) ||
+          (md != NULL && (md->flag & eModifierFlag_OverrideLibrary_Local) != 0));
+}
+
 CDMaskLink *BKE_modifier_calc_data_masks(struct Scene *scene,
                                          Object *ob,
                                          ModifierData *md,