From 8e046cbbd771ef3f8f11a1bd1165023cc0fb2a17 Mon Sep 17 00:00:00 2001
From: Ruslan Shestopalyuk <rshest@meta.com>
Date: Thu, 20 Apr 2023 10:05:53 -0700
Subject: [PATCH] Use stable sort for performance entries (#36998)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/36998

For performance entries that have the same start/end time it makes more sense to report them back to `PerformanceObserver` in the same order they were logged.

This kind of determinism is arguably better both in terms of API, and from the point of view of testing.

Changelog: [Internal]

Reviewed By: javache

Differential Revision: D45142500

fbshipit-source-id: 77ff0093bead45dc2f15efc4b903dc181927565a
---
 .../PerformanceEntryReporter.cpp              |  2 +-
 .../PerformanceEntryReporterTest.cpp          | 28 ++++++++++++++++++-
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/packages/react-native/Libraries/WebPerformance/PerformanceEntryReporter.cpp b/packages/react-native/Libraries/WebPerformance/PerformanceEntryReporter.cpp
index 8c82a5c2a9d..e223156ac94 100644
--- a/packages/react-native/Libraries/WebPerformance/PerformanceEntryReporter.cpp
+++ b/packages/react-native/Libraries/WebPerformance/PerformanceEntryReporter.cpp
@@ -72,7 +72,7 @@ GetPendingEntriesResult PerformanceEntryReporter::popPendingEntries() {
   }
 
   // Sort by starting time (or ending time, if starting times are equal)
-  std::sort(
+  std::stable_sort(
       res.entries.begin(),
       res.entries.end(),
       [](const RawPerformanceEntry &lhs, const RawPerformanceEntry &rhs) {
diff --git a/packages/react-native/Libraries/WebPerformance/__tests__/PerformanceEntryReporterTest.cpp b/packages/react-native/Libraries/WebPerformance/__tests__/PerformanceEntryReporterTest.cpp
index fb2dabc0d96..c5895021ee6 100644
--- a/packages/react-native/Libraries/WebPerformance/__tests__/PerformanceEntryReporterTest.cpp
+++ b/packages/react-native/Libraries/WebPerformance/__tests__/PerformanceEntryReporterTest.cpp
@@ -146,6 +146,10 @@ TEST(PerformanceEntryReporter, PerformanceEntryReporterTestReportMeasures) {
   reporter.measure("measure3", 0.0, 0.0, 5.0, "mark1");
   reporter.measure("measure4", 1.5, 0.0, std::nullopt, std::nullopt, "mark2");
 
+  reporter.mark("mark3", 2.0);
+  reporter.measure("measure5", 2.0, 2.0);
+  reporter.mark("mark4", 2.0);
+
   auto res = reporter.popPendingEntries();
   const auto &entries = res.entries;
 
@@ -207,7 +211,29 @@ TEST(PerformanceEntryReporter, PerformanceEntryReporterTestReportMeasures) {
        0.0,
        std::nullopt,
        std::nullopt,
-       std::nullopt}};
+       std::nullopt},
+      {"mark3",
+       static_cast<int>(PerformanceEntryType::MARK),
+       2.0,
+       0.0,
+       std::nullopt,
+       std::nullopt,
+       std::nullopt},
+      {"mark4",
+       static_cast<int>(PerformanceEntryType::MARK),
+       2.0,
+       0.0,
+       std::nullopt,
+       std::nullopt,
+       std::nullopt},
+      {"measure5",
+       static_cast<int>(PerformanceEntryType::MEASURE),
+       2.0,
+       0.0,
+       std::nullopt,
+       std::nullopt,
+       std::nullopt},
+  };
 
   ASSERT_EQ(expected, entries);
 }