From 78175fe624aaf1169123a89340aa458f3d7259cd Mon Sep 17 00:00:00 2001
From: Gregor <gregor.mitscha-baude@gmx.at>
Date: Wed, 21 Aug 2024 14:16:12 +0200
Subject: [PATCH 1/3] fix int64 mod when the input is negative and result = 0

---
 src/lib/provable/int.ts | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/lib/provable/int.ts b/src/lib/provable/int.ts
index bc4e741f91..e919b17a9e 100644
--- a/src/lib/provable/int.ts
+++ b/src/lib/provable/int.ts
@@ -1334,7 +1334,11 @@ class Int64 extends CircuitValue implements BalanceChange {
     let isNonNegative = this.magnitude
       .equals(UInt64.zero)
       .or(this.sgn.isPositive());
-    rest = Provable.if(isNonNegative, rest, y_.value.sub(rest));
+    rest = Provable.if(
+      isNonNegative.or(rest.equals(0)),
+      rest,
+      y_.value.sub(rest)
+    );
     return new Int64(new UInt64(rest.value));
   }
 

From ac03ac549188a64f4708074adf30b4db1efbf0f0 Mon Sep 17 00:00:00 2001
From: Gregor <gregor.mitscha-baude@gmx.at>
Date: Wed, 21 Aug 2024 14:18:06 +0200
Subject: [PATCH 2/3] changelog

---
 CHANGELOG.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index baf5beaf6a..a6b14ffc8a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,10 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ## [Unreleased](https://github.com/o1-labs/o1js/compare/d6abf1d97...HEAD)
 
+### Fixes
+
+- Fix behavior of `Int64.modV2()` when the input is negative and the remainder should be 0 https://github.com/o1-labs/o1js/pull/1797
+
 ## [1.6.0](https://github.com/o1-labs/o1js/compare/1ad7333e9e...d6abf1d97) - 2024-07-23
 
 ### Added

From ecac253a4002f51a107552fcefc5b2f2aec9dae4 Mon Sep 17 00:00:00 2001
From: Gregor <gregor.mitscha-baude@gmx.at>
Date: Wed, 21 Aug 2024 14:32:31 +0200
Subject: [PATCH 3/3] int64 to bigint

---
 src/lib/provable/int.ts | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/src/lib/provable/int.ts b/src/lib/provable/int.ts
index e919b17a9e..15c64c6249 100644
--- a/src/lib/provable/int.ts
+++ b/src/lib/provable/int.ts
@@ -1147,14 +1147,22 @@ class Int64 extends CircuitValue implements BalanceChange {
     return Int64.create(UInt64.from(obj.magnitude), Sign.fromValue(obj.sgn));
   }
 
+  /**
+   * Turns the {@link Int64} into a {@link BigInt}.
+   */
+  toBigint() {
+    let abs = this.magnitude.toBigInt();
+    let sgn = this.sgn.isPositive().toBoolean() ? 1n : -1n;
+    return sgn * abs;
+  }
+
   /**
    * Turns the {@link Int64} into a string.
    */
   toString() {
-    let abs = this.magnitude.toString();
-    let sgn = this.isPositive().toBoolean() || abs === '0' ? '' : '-';
-    return sgn + abs;
+    return this.toBigint().toString();
   }
+
   isConstant() {
     return this.magnitude.value.isConstant() && this.sgn.isConstant();
   }