[OTLP Exporter] Revert Google.Protobuf version bump

build/Common.nonprod.props

@@ -33,7 +33,7 @@
     <BenchmarkDotNetPkgVer>[0.13.5,0.14)</BenchmarkDotNetPkgVer>
     <CommandLineParserPkgVer>[2.9.1,3.0)</CommandLineParserPkgVer>
     <DotNetXUnitCliVer>[2.3.1,3.0)</DotNetXUnitCliVer>
-    <GoogleProtobufPkgVer>[3.22.0,4.0)</GoogleProtobufPkgVer>
+    <GoogleProtobufPkgVer>[3.19.4,4.0)</GoogleProtobufPkgVer>
     <GrpcAspNetCorePkgVer>[2.50.0,3.0)</GrpcAspNetCorePkgVer>
     <GrpcAspNetCoreServerPkgVer>[2.48.0, 3.0)</GrpcAspNetCoreServerPkgVer>
     <GrpcToolsPkgVer>[2.48.0,3.0)</GrpcToolsPkgVer>

build/Common.props

@@ -27,7 +27,7 @@
       Refer to https://docs.microsoft.com/nuget/concepts/package-versioning for semver syntax.
     -->
     <MinVerPkgVer>[4.2.0,5.0)</MinVerPkgVer>
-    <GoogleProtobufPkgVer>[3.22.0,4.0)</GoogleProtobufPkgVer>
+    <GoogleProtobufPkgVer>[3.19.4,4.0)</GoogleProtobufPkgVer>
     <GrpcPkgVer>[2.44.0,3.0)</GrpcPkgVer>
     <GrpcNetClientPkgVer>[2.43.0,3.0)</GrpcNetClientPkgVer>
     <GrpcToolsPkgVer>[2.44.0,3.0)</GrpcToolsPkgVer>
@@ -49,6 +49,7 @@
     <StyleCopAnalyzersPkgVer>[1.2.0-beta.435,2.0)</StyleCopAnalyzersPkgVer>
     <SystemCollectionsImmutablePkgVer>1.4.0</SystemCollectionsImmutablePkgVer>
     <SystemDiagnosticSourcePkgVer>7.0.0</SystemDiagnosticSourcePkgVer>
+    <SystemReflectionEmitLightweightPkgVer>4.7.0</SystemReflectionEmitLightweightPkgVer>
     <SystemTextEncodingsWebPkgVer>4.7.2</SystemTextEncodingsWebPkgVer>
     <SystemTextJsonPkgVer>4.7.2</SystemTextJsonPkgVer>
     <SystemThreadingTasksExtensionsPkgVer>4.5.4</SystemThreadingTasksExtensionsPkgVer>

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/CHANGELOG.md

@@ -2,6 +2,11 @@
 
 ## Unreleased
 
+* Revert version of `Google.Protobuf` to `3.19.4` (see
+  [#4201](https://github.com/open-telemetry/opentelemetry-dotnet/pull/4201)).
+  This also reintroduces the `System.Reflection.Emit.Lightweight` dependency.
+  ([#4407](https://github.com/open-telemetry/opentelemetry-dotnet/pull/4407))
+
 ## 1.5.0-alpha.2
 
 Released 2023-Mar-31

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/ActivityExtensions.cs

@@ -16,8 +16,11 @@
 
 using System.Collections.Concurrent;
 using System.Diagnostics;
+using System.Reflection;
+using System.Reflection.Emit;
 using System.Runtime.CompilerServices;
 using Google.Protobuf;
+using Google.Protobuf.Collections;
 using OpenTelemetry.Internal;
 using OpenTelemetry.Proto.Collector.Trace.V1;
 using OpenTelemetry.Proto.Common.V1;
@@ -31,6 +34,7 @@ namespace OpenTelemetry.Exporter.OpenTelemetryProtocol.Implementation
     internal static class ActivityExtensions
     {
         private static readonly ConcurrentBag<ScopeSpans> SpanListPool = new();
+        private static readonly Action<RepeatedField<Span>, int> RepeatedFieldOfSpanSetCountAction = CreateRepeatedFieldOfSpanSetCountAction();
 
         internal static void AddBatch(
             this ExportTraceServiceRequest request,
@@ -80,7 +84,7 @@ internal static void Return(this ExportTraceServiceRequest request)
 
             foreach (var scope in resourceSpans.ScopeSpans)
             {
-                scope.Spans.Clear();
+                RepeatedFieldOfSpanSetCountAction(scope.Spans, 0);
                 SpanListPool.Add(scope);
             }
         }
@@ -294,6 +298,27 @@ private static Span.Types.Event ToOtlpEvent(in ActivityEvent activityEvent, SdkL
             return otlpEvent;
         }
 
+        private static Action<RepeatedField<Span>, int> CreateRepeatedFieldOfSpanSetCountAction()
+        {
+            FieldInfo repeatedFieldOfSpanCountField = typeof(RepeatedField<Span>).GetField("count", BindingFlags.NonPublic | BindingFlags.Instance);
+
+            DynamicMethod dynamicMethod = new DynamicMethod(
+                "CreateSetCountAction",
+                null,
+                new[] { typeof(RepeatedField<Span>), typeof(int) },
+                typeof(ActivityExtensions).Module,
+                skipVisibility: true);
+
+            var generator = dynamicMethod.GetILGenerator();
+
+            generator.Emit(OpCodes.Ldarg_0);
+            generator.Emit(OpCodes.Ldarg_1);
+            generator.Emit(OpCodes.Stfld, repeatedFieldOfSpanCountField);
+            generator.Emit(OpCodes.Ret);
+
+            return (Action<RepeatedField<Span>, int>)dynamicMethod.CreateDelegate(typeof(Action<RepeatedField<Span>, int>));
+        }
+
         private struct TagEnumerationState : PeerServiceResolver.IPeerServiceState
         {
             public SdkLimitOptions SdkLimitOptions;

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/MetricItemExtensions.cs

@@ -15,6 +15,8 @@
 // </copyright>
 
 using System.Collections.Concurrent;
+using System.Reflection;
+using System.Reflection.Emit;
 using System.Runtime.CompilerServices;
 using Google.Protobuf;
 using Google.Protobuf.Collections;
@@ -29,6 +31,7 @@ namespace OpenTelemetry.Exporter.OpenTelemetryProtocol.Implementation
     internal static class MetricItemExtensions
     {
         private static readonly ConcurrentBag<OtlpMetrics.ScopeMetrics> MetricListPool = new();
+        private static readonly Action<RepeatedField<OtlpMetrics.Metric>, int> RepeatedFieldOfMetricSetCountAction = CreateRepeatedFieldOfMetricSetCountAction();
 
         internal static void AddMetrics(
             this OtlpCollector.ExportMetricsServiceRequest request,
@@ -79,7 +82,7 @@ internal static void Return(this OtlpCollector.ExportMetricsServiceRequest reque
 
             foreach (var scope in resourceMetrics.ScopeMetrics)
             {
-                scope.Metrics.Clear();
+                RepeatedFieldOfMetricSetCountAction(scope.Metrics, 0);
                 MetricListPool.Add(scope);
             }
         }
@@ -422,5 +425,26 @@ private static OtlpMetrics.Exemplar ToOtlpExemplar(this IExemplar exemplar)
             return otlpExemplar;
         }
         */
+
+        private static Action<RepeatedField<OtlpMetrics.Metric>, int> CreateRepeatedFieldOfMetricSetCountAction()
+        {
+            FieldInfo repeatedFieldOfMetricCountField = typeof(RepeatedField<OtlpMetrics.Metric>).GetField("count", BindingFlags.NonPublic | BindingFlags.Instance);
+
+            DynamicMethod dynamicMethod = new DynamicMethod(
+                "CreateSetCountAction",
+                null,
+                new[] { typeof(RepeatedField<OtlpMetrics.Metric>), typeof(int) },
+                typeof(MetricItemExtensions).Module,
+                skipVisibility: true);
+
+            var generator = dynamicMethod.GetILGenerator();
+
+            generator.Emit(OpCodes.Ldarg_0);
+            generator.Emit(OpCodes.Ldarg_1);
+            generator.Emit(OpCodes.Stfld, repeatedFieldOfMetricCountField);
+            generator.Emit(OpCodes.Ret);
+
+            return (Action<RepeatedField<OtlpMetrics.Metric>, int>)dynamicMethod.CreateDelegate(typeof(Action<RepeatedField<OtlpMetrics.Metric>, int>));
+        }
     }
 }

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/OpenTelemetry.Exporter.OpenTelemetryProtocol.csproj

@@ -19,6 +19,7 @@
     <PackageReference Include="Grpc" Version="$(GrpcPkgVer)" Condition="'$(TargetFramework)' == 'netstandard2.0' OR '$(TargetFramework)' == 'net462'" />
     <PackageReference Include="Google.Protobuf" Version="$(GoogleProtobufPkgVer)" />
     <PackageReference Include="Grpc.Tools" Version="$(GrpcToolsPkgVer)" PrivateAssets="all" />
+    <PackageReference Include="System.Reflection.Emit.Lightweight" Version="$(SystemReflectionEmitLightweightPkgVer)" Condition="'$(TargetFramework)' != 'net6.0'" />
   </ItemGroup>
 
   <ItemGroup>