From d90608ddbf9b437c59de4e91520c016029b59f11 Mon Sep 17 00:00:00 2001
From: Anna Shaleva <shaleva.ann@nspcc.ru>
Date: Thu, 3 Aug 2023 15:52:12 +0300
Subject: [PATCH] vm: increase BigInt parsing precision

Follow the https://github.com/neo-project/neo/pull/2883.

Signed-off-by: Anna Shaleva <shaleva.ann@nspcc.ru>
---
 pkg/vm/stackitem/json.go      | 6 +++---
 pkg/vm/stackitem/json_test.go | 6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/pkg/vm/stackitem/json.go b/pkg/vm/stackitem/json.go
index 508d91fbd..482ff27ae 100644
--- a/pkg/vm/stackitem/json.go
+++ b/pkg/vm/stackitem/json.go
@@ -27,9 +27,9 @@ const MaxAllowedInteger = 2<<53 - 1
 const MaxJSONDepth = 10
 
 // MaxIntegerPrec is the maximum precision allowed for big.Integer parsing.
-// It equals to the reference value and doesn't allow to precisely parse big
-// numbers, see the https://github.com/neo-project/neo/issues/2879.
-const MaxIntegerPrec = 53
+// It allows to properly parse integer numbers that our 256-bit VM is able to
+// handle.
+const MaxIntegerPrec = 1<<8 + 1
 
 // ErrInvalidValue is returned when an item value doesn't fit some constraints
 // during serialization or deserialization.
diff --git a/pkg/vm/stackitem/json_test.go b/pkg/vm/stackitem/json_test.go
index 679da1b3b..0895b283d 100644
--- a/pkg/vm/stackitem/json_test.go
+++ b/pkg/vm/stackitem/json_test.go
@@ -134,10 +134,10 @@ func TestFromToJSON(t *testing.T) {
 // the C# one, ref. https://github.com/neo-project/neo/issues/2879.
 func TestFromJSON_CompatBigInt(t *testing.T) {
 	tcs := map[string]string{
-		`9.05e+28`:   "90499999999999993918259200000",
+		`9.05e+28`:   "90500000000000000000000000000",
 		`1.871e+21`:  "1871000000000000000000",
-		`3.0366e+32`: "303660000000000004445016810323968",
-		`1e+30`:      "1000000000000000019884624838656",
+		`3.0366e+32`: "303660000000000000000000000000000",
+		`1e+30`:      "1000000000000000000000000000000",
 	}
 	for in, expected := range tcs {
 		t.Run(in, func(t *testing.T) {