From a65fe3184298c52e84f6338cbabb0198f5a3877a Mon Sep 17 00:00:00 2001
From: Kevaundray Wedderburn <kevtheappdev@gmail.com>
Date: Sat, 12 Oct 2024 16:36:11 +0100
Subject: [PATCH] add note on zero check

---
 crypto/bn256/gnark/pairing.go | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/crypto/bn256/gnark/pairing.go b/crypto/bn256/gnark/pairing.go
index a9e049111d..b9b6405534 100644
--- a/crypto/bn256/gnark/pairing.go
+++ b/crypto/bn256/gnark/pairing.go
@@ -19,8 +19,17 @@ func PairingCheck(a_ []*G1, b_ []*G2) bool {
 	a := getInnerG1s(a_)
 	b := getInnerG2s(b_)
 
-	// Check if input is empty
-	if len(a) == 0 {
+	// Assume that len(a) == len(b)
+	//
+	// The pairing function will return
+	// false, if this is not the case.
+	size := len(a)
+
+	// Check if input is empty -- gnark will
+	// return false on an empty input, however
+	// the ossified behavior is to return true
+	// on an empty input, so we add this if statement.
+	if size == 0 {
 		return true
 	}