Bugfixes for various ID-block references (Constraints, NLA)

* ID-blocks referenced by Constraints but not being used as the target objects
(such as Actions in the Action Constraint, or Text Blocks in PyConstraints) now
get usercounts for being referenced in this way. This should fix ancient bugs
such as [#19205] and [#8593]. More tests still needed to verify that this
does now play nicely with proxies.

* Changing actions used by NLA strips should now update the usercounts
accordingly

1 files changed, 12 insertions, 3 deletions

diff --git a/source/blender/blenloader/intern/readfile.c b/source/blender/blenloader/intern/readfile.c
index 231c1ab8d03..ec7d58035b4 100644
--- a/source/blender/blenloader/intern/readfile.c
+++ b/source/blender/blenloader/intern/readfile.c
@@ -2473,10 +2473,19 @@ typedef struct tConstraintLinkData {
 	ID *id;
 } tConstraintLinkData;
 /* callback function used to relink constraint ID-links */
-static void lib_link_constraint_cb(bConstraint *UNUSED(con), ID **idpoin, void *userdata)
+static void lib_link_constraint_cb(bConstraint *UNUSED(con), ID **idpoin, short isReference, void *userdata)
 {
 	tConstraintLinkData *cld= (tConstraintLinkData *)userdata;
-	*idpoin = newlibadr(cld->fd, cld->id->lib, *idpoin);
+	
+	/* for reference types, we need to increment the usercounts on load... */
+	if (isReference) {
+		/* reference type - with usercount */
+		*idpoin = newlibadr_us(cld->fd, cld->id->lib, *idpoin);
+	}
+	else {
+		/* target type - no usercount needed */
+		*idpoin = newlibadr(cld->fd, cld->id->lib, *idpoin);
+	}
 }
 
 static void lib_link_constraints(FileData *fd, ID *id, ListBase *conlist)
@@ -8115,7 +8124,7 @@ typedef struct tConstraintExpandData {
 	Main *mainvar;
 } tConstraintExpandData;
 /* callback function used to expand constraint ID-links */
-static void expand_constraint_cb(bConstraint *UNUSED(con), ID **idpoin, void *userdata)
+static void expand_constraint_cb(bConstraint *UNUSED(con), ID **idpoin, short UNUSED(isReference), void *userdata)
 {
 	tConstraintExpandData *ced= (tConstraintExpandData *)userdata;
 	expand_doit(ced->fd, ced->mainvar, *idpoin);