Fix #22534 linking object data for two forces results in crash.

This is because the make_links_data_exec don't check for the
object type like before, so try to access the obdata of an empty
and blender crash.

The solution is not the best, we have a new function
allow_make_links_data to check if we can links data from one
object to another.

The real solution is build the menu like the 2.4x, so only
show the options that we allow for the object type that
we have select/active.

Matt, any suggestion ?

1 files changed, 58 insertions, 33 deletions

diff --git a/source/blender/editors/object/object_relations.c b/source/blender/editors/object/object_relations.c
index 1f970b50716..28eb919dbe7 100644
--- a/source/blender/editors/object/object_relations.c
+++ b/source/blender/editors/object/object_relations.c
@@ -1188,6 +1188,29 @@ enum {
 	MAKE_LINKS_MODIFIERS
 };
 
+/* Return 1 if make link data is allow, zero otherwise */
+static int allow_make_links_data(int ev, Object *ob, Object *obt)
+{
+	if (ev == MAKE_LINKS_OBDATA) {
+		if (ob->type == OB_MESH && obt->type == OB_MESH)
+			return(1);
+	}
+	else if (ev == MAKE_LINKS_MATERIALS) {
+		if ((ob->type == OB_MESH || ob->type == OB_CURVE || ob->type == OB_FONT || ob->type == OB_SURF || ob->type == OB_MBALL) &&
+		    (obt->type == OB_MESH || obt->type == OB_CURVE || obt->type == OB_FONT || obt->type == OB_SURF || obt->type == OB_MBALL))
+			return(1);
+	}
+	else if (ev == MAKE_LINKS_ANIMDATA)
+		return(1);
+	else if (ev == MAKE_LINKS_DUPLIGROUP)
+		return(1);
+	else if (ev == MAKE_LINKS_MODIFIERS) {
+		if (ob->type != OB_EMPTY && obt->type != OB_EMPTY)
+			return(1);
+	}
+	return(0);
+}
+
 static int make_links_data_exec(bContext *C, wmOperator *op)
 {
 	int event = RNA_int_get(op->ptr, "type");
@@ -1199,43 +1222,45 @@ static int make_links_data_exec(bContext *C, wmOperator *op)
 
 	CTX_DATA_BEGIN(C, Object*, obt, selected_editable_objects) {
 		if(ob != obt) {
-			switch(event) {
-			case MAKE_LINKS_OBDATA: /* obdata */
-				id= obt->data;
-				id->us--;
+			if (allow_make_links_data(event, ob, obt)) {
+				switch(event) {
+				case MAKE_LINKS_OBDATA: /* obdata */
+					id= obt->data;
+					id->us--;
 
-				id= ob->data;
-				id_us_plus(id);
-				obt->data= id;
+					id= ob->data;
+					id_us_plus(id);
+					obt->data= id;
 
-				/* if amount of material indices changed: */
-				test_object_materials(obt->data);
+					/* if amount of material indices changed: */
+					test_object_materials(obt->data);
 
-				obt->recalc |= OB_RECALC_DATA;
-				break;
-			case MAKE_LINKS_MATERIALS:
-				/* new approach, using functions from kernel */
-				for(a=0; a<ob->totcol; a++) {
-					Material *ma= give_current_material(ob, a+1);
-					assign_material(obt, ma, a+1);	/* also works with ma==NULL */
-				}
-				break;
-			case MAKE_LINKS_ANIMDATA:
-				BKE_copy_animdata_id((ID *)obt, (ID *)ob);
-				BKE_copy_animdata_id((ID *)obt->data, (ID *)ob->data);
-				break;
-			case MAKE_LINKS_DUPLIGROUP:
-				if(ob->dup_group) ob->dup_group->id.us--;
-				obt->dup_group= ob->dup_group;
-				if(obt->dup_group) {
-					id_us_plus((ID *)obt->dup_group);
-					obt->transflag |= OB_DUPLIGROUP;
+					obt->recalc |= OB_RECALC_DATA;
+					break;
+				case MAKE_LINKS_MATERIALS:
+					/* new approach, using functions from kernel */
+					for(a=0; a<ob->totcol; a++) {
+						Material *ma= give_current_material(ob, a+1);
+						assign_material(obt, ma, a+1);	/* also works with ma==NULL */
+					}
+					break;
+				case MAKE_LINKS_ANIMDATA:
+					BKE_copy_animdata_id((ID *)obt, (ID *)ob);
+					BKE_copy_animdata_id((ID *)obt->data, (ID *)ob->data);
+					break;
+				case MAKE_LINKS_DUPLIGROUP:
+					if(ob->dup_group) ob->dup_group->id.us--;
+					obt->dup_group= ob->dup_group;
+					if(obt->dup_group) {
+						id_us_plus((ID *)obt->dup_group);
+						obt->transflag |= OB_DUPLIGROUP;
+					}
+					break;
+				case MAKE_LINKS_MODIFIERS:
+					object_link_modifiers(obt, ob);
+					obt->recalc |= OB_RECALC;
+					break;
 				}
-				break;
-			case MAKE_LINKS_MODIFIERS:
-				object_link_modifiers(obt, ob);
-				obt->recalc |= OB_RECALC;
-				break;
 			}
 		}
 	}