From a97c292a05aa32fd7334ed0470704f95b911529f Mon Sep 17 00:00:00 2001
From: Per K <perkj@webrtc.org>
Date: Thu, 30 May 2024 10:40:52 +0000
Subject: [PATCH] Ensure packets are sorted on arrival time in
 CongestionControlFeedbackGenerator

Without this, packets may be sorted in the wrong order.

Bug: webrtc:42225697
Change-Id: Ib9a72cdc7cb8f7ef6ca1571d095a6474215a83f2
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/352821
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Commit-Queue: Per Kjellander <perkj@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#42411}
---
 .../congestion_control_feedback_generator.cc                | 6 ++----
 .../congestion_control_feedback_generator_unittest.cc       | 3 +--
 2 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/modules/remote_bitrate_estimator/congestion_control_feedback_generator.cc b/modules/remote_bitrate_estimator/congestion_control_feedback_generator.cc
index 6b8c7c21e9..aba35861cc 100644
--- a/modules/remote_bitrate_estimator/congestion_control_feedback_generator.cc
+++ b/modules/remote_bitrate_estimator/congestion_control_feedback_generator.cc
@@ -95,10 +95,8 @@ void CongestionControlFeedbackGenerator::SetTransportOverhead(
 
 void CongestionControlFeedbackGenerator::SendFeedback(Timestamp now) {
   absl::c_sort(packets_, [](const PacketInfo& a, const PacketInfo& b) {
-    if (a.ssrc == b.ssrc) {
-      return a.unwrapped_sequence_number < b.unwrapped_sequence_number;
-    }
-    return a.ssrc < b.ssrc;
+    return std::tie(a.ssrc, a.unwrapped_sequence_number, a.arrival_time) <
+           std::tie(b.ssrc, b.unwrapped_sequence_number, b.arrival_time);
   });
   uint32_t compact_ntp =
       CompactNtp(env_.clock().ConvertTimestampToNtpTime(now));
diff --git a/modules/remote_bitrate_estimator/congestion_control_feedback_generator_unittest.cc b/modules/remote_bitrate_estimator/congestion_control_feedback_generator_unittest.cc
index b8cb828cd4..ecc6e9a95e 100644
--- a/modules/remote_bitrate_estimator/congestion_control_feedback_generator_unittest.cc
+++ b/modules/remote_bitrate_estimator/congestion_control_feedback_generator_unittest.cc
@@ -301,8 +301,7 @@ TEST(CongestionControlFeedbackGeneratorTest,
   generator.Process(clock.CurrentTime());
 }
 
-// TODO: bugs.webrtc.org/42225697 - Figure out why this test is flaky.
-TEST(DISABLED_CongestionControlFeedbackGeneratorTest,
+TEST(CongestionControlFeedbackGeneratorTest,
      ReportsFirstReceivedPacketArrivalTimeButEcnFromCePacketIfDuplicate) {
   MockFunction<void(std::vector<std::unique_ptr<rtcp::RtcpPacket>>)>
       rtcp_sender;