diff --git a/combine-diff.c b/combine-diff.c
index 5aa1104..ec8df39 100644
--- a/combine-diff.c
+++ b/combine-diff.c
@@ -213,6 +213,7 @@
 
 	parent_file.ptr = grab_blob(parent, &sz);
 	parent_file.size = sz;
+	memset(&xpp, 0, sizeof(xpp));
 	xpp.flags = XDF_NEED_MINIMAL;
 	memset(&xecfg, 0, sizeof(xecfg));
 	memset(&state, 0, sizeof(state));