From 60b9fa995d1b0e8cbb0b1825d37221280cee940d Mon Sep 17 00:00:00 2001
From: Robert Stupp <snazy@snazy.de>
Date: Thu, 16 Jul 2026 10:24:45 +0200
Subject: [PATCH] Use unsigned arithmetic for uint division

CEL uint values above Long.MAX_VALUE are stored in signed long slots, so Java signed / and % produced incorrect results for high unsigned operands.

Use Long.divideUnsigned() and Long.remainderUnsigned(), and cover high-bit operands in uint division and modulo tests.
---
 .../java/org/projectnessie/cel/common/types/UintT.java     | 4 ++--
 .../java/org/projectnessie/cel/common/types/UintTest.java  | 7 +++++++
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/core/src/main/java/org/projectnessie/cel/common/types/UintT.java b/core/src/main/java/org/projectnessie/cel/common/types/UintT.java
index 04d88528..10e6bcab 100644
--- a/core/src/main/java/org/projectnessie/cel/common/types/UintT.java
+++ b/core/src/main/java/org/projectnessie/cel/common/types/UintT.java
@@ -249,7 +249,7 @@ public Val divide(Val other) {
     if (otherInt == 0L) {
       return divideByZero();
     }
-    return uintOf(i / otherInt);
+    return uintOf(Long.divideUnsigned(i, otherInt));
   }
 
   /** Modulo implements traits.Modder.Modulo. */
@@ -262,7 +262,7 @@ public Val modulo(Val other) {
     if (otherInt == 0L) {
       return modulusByZero();
     }
-    return uintOf(i % otherInt);
+    return uintOf(Long.remainderUnsigned(i, otherInt));
   }
 
   /** Multiply implements traits.Multiplier.Multiply. */
diff --git a/core/src/test/java/org/projectnessie/cel/common/types/UintTest.java b/core/src/test/java/org/projectnessie/cel/common/types/UintTest.java
index 4622b39d..96462232 100644
--- a/core/src/test/java/org/projectnessie/cel/common/types/UintTest.java
+++ b/core/src/test/java/org/projectnessie/cel/common/types/UintTest.java
@@ -164,6 +164,9 @@ void uintConvertToType() {
   @Test
   void uintDivide() {
     assertThat(uintOf(3).divide(uintOf(2)).equal(uintOf(1))).isSameAs(True);
+    assertThat(uintOf(-1L).divide(uintOf(2)).equal(uintOf(Long.MAX_VALUE))).isSameAs(True);
+    assertThat(uintOf(-1L).divide(uintOf(Long.MIN_VALUE)).equal(uintOf(1))).isSameAs(True);
+    assertThat(uintOf(Long.MIN_VALUE).divide(uintOf(2)).equal(uintOf(1L << 62))).isSameAs(True);
     assertThat(UintZero.divide(UintZero))
         .isInstanceOf(Err.class)
         .extracting(Object::toString)
@@ -196,6 +199,10 @@ void uintEqual() {
   @Test
   void uintModulo() {
     assertThat(uintOf(21).modulo(uintOf(2)).equal(uintOf(1))).isSameAs(True);
+    assertThat(uintOf(-1L).modulo(uintOf(2)).equal(uintOf(1))).isSameAs(True);
+    assertThat(uintOf(-1L).modulo(uintOf(Long.MIN_VALUE)).equal(uintOf(Long.MAX_VALUE)))
+        .isSameAs(True);
+    assertThat(uintOf(Long.MIN_VALUE).modulo(uintOf(3)).equal(uintOf(2))).isSameAs(True);
     assertThat(uintOf(21).modulo(UintZero))
         .isInstanceOf(Err.class)
         .extracting(Object::toString)