diff -r d5ce99a6db52 -r 49fa0b31ee1d mercurial/cext/revlog.c
--- a/mercurial/cext/revlog.c	Wed Nov 20 13:03:22 2019 -0500
+++ b/mercurial/cext/revlog.c	Thu Dec 05 20:41:23 2019 +0100
@@ -2522,7 +2522,10 @@
 				index_invalidate_added(self, 0);
 			if (self->ntrev > start)
 				self->ntrev = (int)start;
+		} else if (self->added) {
+			Py_CLEAR(self->added);
 		}
+
 		self->length = start;
 		if (start < self->raw_length) {
 			if (self->cache) {