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, 15 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/constraint.c b/source/blender/blenkernel/intern/constraint.c
index 28121206a90..982e91dd1e0 100644
--- a/source/blender/blenkernel/intern/constraint.c
+++ b/source/blender/blenkernel/intern/constraint.c
@@ -5754,6 +5754,7 @@ bConstraint *BKE_constraint_duplicate_ex(bConstraint *src, const int flag, const
   bConstraint *dst = MEM_dupallocN(src);
   constraint_copy_data_ex(dst, src, flag, do_extern);
   dst->next = dst->prev = NULL;
+  dst->flag |= CONSTRAINT_OVERRIDE_LIBRARY_LOCAL;
   return dst;
 }
 
@@ -5788,6 +5789,7 @@ void BKE_constraints_copy_ex(ListBase *dst, const ListBase *src, const int flag,
   for (con = dst->first, srccon = src->first; con && srccon;
        srccon = srccon->next, con = con->next) {
     constraint_copy_data_ex(con, srccon, flag, do_extern);
+    con->flag |= CONSTRAINT_OVERRIDE_LIBRARY_LOCAL;
   }
 }
 
@@ -5954,6 +5956,19 @@ static bConstraint *constraint_find_original_for_update(bConstraintOb *cob, bCon
   return orig_con;
 }
 
+/**
+ * Check whether given constraint is local when the object is a library override.
+ *
+ * \param con May be NULL, in which case we consider it as a non-local constraint case.
+ *
+ * \note This check is only valid for a liboverride data-block, it always return \a true otherwise.
+ */
+bool BKE_constraint_is_local_in_liboverride(const Object *ob, const bConstraint *con)
+{
+  return (!ID_IS_OVERRIDE_LIBRARY(ob) ||
+          (con != NULL && (con->flag & CONSTRAINT_OVERRIDE_LIBRARY_LOCAL) != 0));
+}
+
 /* -------- Constraints and Proxies ------- */
 
 /* Rescue all constraints tagged as being CONSTRAINT_PROXY_LOCAL