From 0d9c2fc763dd766b868665a302ff4526748c4b36 Mon Sep 17 00:00:00 2001
From: Abseil Team <absl-team@google.com>
Date: Tue, 2 Jul 2024 08:40:43 -0700
Subject: Replace signed integer overflow, since that's undefined behavior,
 with unsigned integer overflow.

PiperOrigin-RevId: 648730502
Change-Id: I662c365c59be9e51f565fd215d284a96b7bd8743
---
 absl/synchronization/internal/graphcycles_test.cc | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

(limited to 'absl/synchronization/internal/graphcycles_test.cc')

diff --git a/absl/synchronization/internal/graphcycles_test.cc b/absl/synchronization/internal/graphcycles_test.cc
index 3c6ef798..47410aad 100644
--- a/absl/synchronization/internal/graphcycles_test.cc
+++ b/absl/synchronization/internal/graphcycles_test.cc
@@ -14,6 +14,7 @@
 
 #include "absl/synchronization/internal/graphcycles.h"
 
+#include <climits>
 #include <map>
 #include <random>
 #include <unordered_set>
@@ -458,6 +459,24 @@ TEST_F(GraphCyclesTest, ManyEdges) {
   CheckInvariants(g_);
 }
 
+TEST(GraphCycles, IntegerOverflow) {
+  GraphCycles graph_cycles;
+  char *buf = (char *)nullptr;
+  GraphId prev_id = graph_cycles.GetId(buf);
+  buf += 1;
+  GraphId id = graph_cycles.GetId(buf);
+  ASSERT_TRUE(graph_cycles.InsertEdge(prev_id, id));
+
+  // INT_MAX / 40 is enough to cause an overflow when multiplied by 41.
+  graph_cycles.TestOnlyAddNodes(INT_MAX / 40);
+
+  buf += 1;
+  GraphId newid = graph_cycles.GetId(buf);
+  graph_cycles.HasEdge(prev_id, newid);
+
+  graph_cycles.RemoveNode(buf);
+}
+
 }  // namespace synchronization_internal
 ABSL_NAMESPACE_END
 }  // namespace absl
-- 
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