From ff393dbd8a107f8bc86555b48b66d50311a06a64 Mon Sep 17 00:00:00 2001
From: Vern Paxson <vern@corelight.com>
Date: Wed, 14 Apr 2021 18:16:19 -0700
Subject: [PATCH] fix using ++/-- to vectors that contain holes

---
 src/Expr.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/Expr.cc b/src/Expr.cc
index b5ac3d56d5..56f0420b05 100644
--- a/src/Expr.cc
+++ b/src/Expr.cc
@@ -1239,7 +1239,8 @@ ValPtr IncrExpr::Eval(Frame* f) const
 		for ( unsigned int i = 0; i < v_vec->Size(); ++i )
 			{
 			auto elt = v_vec->ValAt(i);
-			v_vec->Assign(i, DoSingleEval(f, elt.get()));
+			if ( elt )
+				v_vec->Assign(i, DoSingleEval(f, elt.get()));
 			}
 
 		op->Assign(f, std::move(v_vec));