From 65032f0c44f9e61472917998228a50a8deaa64aa Mon Sep 17 00:00:00 2001
From: Enrico Minack <github@enrico.minack.dev>
Date: Fri, 8 Nov 2024 09:56:07 +0100
Subject: [PATCH] Make arrow.flight.Timestamp truely nanoseconds precision

---
 cpp/src/arrow/flight/flight_internals_test.cc | 18 ++++++------------
 cpp/src/arrow/flight/types.h                  |  3 ++-
 2 files changed, 8 insertions(+), 13 deletions(-)

diff --git a/cpp/src/arrow/flight/flight_internals_test.cc b/cpp/src/arrow/flight/flight_internals_test.cc
index 3f233cb7b74e5..ab2f8c7830786 100644
--- a/cpp/src/arrow/flight/flight_internals_test.cc
+++ b/cpp/src/arrow/flight/flight_internals_test.cc
@@ -184,12 +184,9 @@ TEST(FlightTypes, FlightDescriptor) {
 TEST(FlightTypes, FlightEndpoint) {
   ASSERT_OK_AND_ASSIGN(auto location1, Location::ForGrpcTcp("localhost", 1024));
   ASSERT_OK_AND_ASSIGN(auto location2, Location::ForGrpcTls("localhost", 1024));
-  // 2023-06-19 03:14:06.004330100
-  // We must use microsecond resolution here for portability.
-  // std::chrono::system_clock::time_point may not provide nanosecond
-  // resolution on some platforms such as Windows.
+  // 2023-06-19 03:14:06.004339123
   const auto expiration_time_duration =
-      std::chrono::seconds{1687144446} + std::chrono::nanoseconds{4339000};
+      std::chrono::seconds{1687144446} + std::chrono::nanoseconds{4339123};
   Timestamp expiration_time(
       std::chrono::duration_cast<Timestamp::duration>(expiration_time_duration));
   std::vector<FlightEndpoint> values = {
@@ -210,7 +207,7 @@ TEST(FlightTypes, FlightEndpoint) {
       "<FlightEndpoint ticket=<Ticket ticket='bar'> locations=[] "
       "expiration_time=null app_metadata='DEADBEEF'>",
       "<FlightEndpoint ticket=<Ticket ticket='foo'> locations=[] "
-      "expiration_time=2023-06-19 03:14:06.004339000 app_metadata=''>",
+      "expiration_time=2023-06-19 03:14:06.004339123 app_metadata=''>",
       "<FlightEndpoint ticket=<Ticket ticket='foo'> locations="
       "[grpc+tcp://localhost:1024] expiration_time=null app_metadata=''>",
       "<FlightEndpoint ticket=<Ticket ticket='bar'> locations="
@@ -271,12 +268,9 @@ TEST(FlightTypes, PollInfo) {
   auto desc = FlightDescriptor::Command("foo");
   auto endpoint = FlightEndpoint{Ticket{"foo"}, {}, std::nullopt, ""};
   auto info = MakeFlightInfo(schema, desc, {endpoint}, -1, 42, true, "");
-  // 2023-06-19 03:14:06.004330100
-  // We must use microsecond resolution here for portability.
-  // std::chrono::system_clock::time_point may not provide nanosecond
-  // resolution on some platforms such as Windows.
+  // 2023-06-19 03:14:06.004339123
   const auto expiration_time_duration =
-      std::chrono::seconds{1687144446} + std::chrono::nanoseconds{4339000};
+      std::chrono::seconds{1687144446} + std::chrono::nanoseconds{4339123};
   Timestamp expiration_time(
       std::chrono::duration_cast<Timestamp::duration>(expiration_time_duration));
   std::vector<PollInfo> values = {
@@ -292,7 +286,7 @@ TEST(FlightTypes, PollInfo) {
           "progress=null expiration_time=null>",
       "<PollInfo info=" + info.ToString() +
           " descriptor=<FlightDescriptor cmd='poll'> "
-          "progress=0.1 expiration_time=2023-06-19 03:14:06.004339000>",
+          "progress=0.1 expiration_time=2023-06-19 03:14:06.004339123>",
       "<PollInfo info=null descriptor=null progress=null expiration_time=null>",
   };
 
diff --git a/cpp/src/arrow/flight/types.h b/cpp/src/arrow/flight/types.h
index b6309d0af2a71..8b612bd55ce91 100644
--- a/cpp/src/arrow/flight/types.h
+++ b/cpp/src/arrow/flight/types.h
@@ -80,7 +80,8 @@ class FlightServerBase;
 /// > all minutes are 60 seconds long, i.e. leap seconds are "smeared"
 /// > so that no leap second table is needed for interpretation. Range
 /// > is from 0001-01-01T00:00:00Z to 9999-12-31T23:59:59.999999999Z.
-using Timestamp = std::chrono::system_clock::time_point;
+using Timestamp =
+    std::chrono::time_point<std::chrono::system_clock, std::chrono::nanoseconds>;
 
 /// \brief A Flight-specific status code.  Used to encode some
 ///   additional status codes into an Arrow Status.