X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/7ae71ad1ec1fe9ab2aff04efc277b7427f933ea9..6b5b7e0caf05fae77569061d2487e7de9bcfda75:/src/src/expand.c

diff --git a/src/src/expand.c b/src/src/expand.c
index 2c29c26d5..26f7f10ac 100644
--- a/src/src/expand.c
+++ b/src/src/expand.c
@@ -2066,7 +2066,8 @@ switch (vp->type)
   case vtype_string_func:
     {
     stringptr_fn_t * fn = (stringptr_fn_t *) val;
-    return fn();
+    uschar* s = fn();
+    return s ? s : US"";
     }
 
   case vtype_pspace: