From 0adee5aeccf67cecc4064af3f0037cfc864131bb Mon Sep 17 00:00:00 2001
From: Sebastian Stehle <sebastian@squidex.io>
Date: Tue, 6 Sep 2022 19:51:35 +0200
Subject: [PATCH] Fix null tags. (#566)

* Fix null tags.
---
 .../Implementation/ActivityExtensions.cs                   | 6 ++++--
 .../StackdriverTraceExporter.cs                            | 6 +++++-
 .../OpenTelemetry.Exporter.Stackdriver.Tests.csproj        | 2 +-
 .../StackdriverExporterTests.cs                            | 7 ++++---
 4 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/src/OpenTelemetry.Exporter.Stackdriver/Implementation/ActivityExtensions.cs b/src/OpenTelemetry.Exporter.Stackdriver/Implementation/ActivityExtensions.cs
index aef78c1e37..66cc89a6f0 100644
--- a/src/OpenTelemetry.Exporter.Stackdriver/Implementation/ActivityExtensions.cs
+++ b/src/OpenTelemetry.Exporter.Stackdriver/Implementation/ActivityExtensions.cs
@@ -120,7 +120,7 @@ public static Span.Types.Link ToLink(this ActivityLink link)
                 {
                     link.Tags.ToDictionary(
                         att => att.Key,
-                        att => att.Value.ToAttributeValue()),
+                        att => att.Value?.ToAttributeValue()),
                 },
             };
         }
@@ -128,7 +128,7 @@ public static Span.Types.Link ToLink(this ActivityLink link)
         return ret;
     }
 
-    public static AttributeValue ToAttributeValue(this object av)
+    public static AttributeValue ToAttributeValue(this object? av)
     {
         switch (av)
         {
@@ -146,6 +146,8 @@ public static AttributeValue ToAttributeValue(this object av)
                 {
                     StringValue = new TruncatableString() { Value = d.ToString() },
                 };
+            case null:
+                return new AttributeValue();
             default:
                 return new AttributeValue()
                 {
diff --git a/src/OpenTelemetry.Exporter.Stackdriver/StackdriverTraceExporter.cs b/src/OpenTelemetry.Exporter.Stackdriver/StackdriverTraceExporter.cs
index 69df0cfd40..222c5c12f0 100644
--- a/src/OpenTelemetry.Exporter.Stackdriver/StackdriverTraceExporter.cs
+++ b/src/OpenTelemetry.Exporter.Stackdriver/StackdriverTraceExporter.cs
@@ -105,7 +105,11 @@ public override ExportResult Export(in Batch<Activity> batchActivity)
 
         foreach (var activity in batchActivity)
         {
-            batchSpansRequest.Spans.Add(activity.ToSpan(this.googleCloudProjectId.ProjectId));
+            // It should never happen that the time has no correct kind, only if OpenTelemetry is used incorrectly.
+            if (activity.StartTimeUtc.Kind == DateTimeKind.Utc)
+            {
+                batchSpansRequest.Spans.Add(activity.ToSpan(this.googleCloudProjectId.ProjectId));
+            }
         }
 
         // avoid cancelling here: this is no return point: if we reached this point
diff --git a/test/OpenTelemetry.Exporter.Stackdriver.Tests/OpenTelemetry.Exporter.Stackdriver.Tests.csproj b/test/OpenTelemetry.Exporter.Stackdriver.Tests/OpenTelemetry.Exporter.Stackdriver.Tests.csproj
index b641dccca8..75e8545346 100644
--- a/test/OpenTelemetry.Exporter.Stackdriver.Tests/OpenTelemetry.Exporter.Stackdriver.Tests.csproj
+++ b/test/OpenTelemetry.Exporter.Stackdriver.Tests/OpenTelemetry.Exporter.Stackdriver.Tests.csproj
@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <Description>Unit test project for Stackdriver Exporter for OpenTelemetry</Description>
     <TargetFrameworks>netcoreapp3.1;net6.0</TargetFrameworks>
diff --git a/test/OpenTelemetry.Exporter.Stackdriver.Tests/StackdriverExporterTests.cs b/test/OpenTelemetry.Exporter.Stackdriver.Tests/StackdriverExporterTests.cs
index 57c9e58b79..509d831452 100644
--- a/test/OpenTelemetry.Exporter.Stackdriver.Tests/StackdriverExporterTests.cs
+++ b/test/OpenTelemetry.Exporter.Stackdriver.Tests/StackdriverExporterTests.cs
@@ -107,7 +107,7 @@ public void StackdriverExporter_TraceClientThrows_ExportResultFailure()
 
         for (int i = 0; i < 10; i++)
         {
-            using Activity activity = source.StartActivity("Test Activity");
+            using Activity activity = CreateTestActivity();
             processor.OnEnd(activity);
         }
 
@@ -147,7 +147,7 @@ public void StackdriverExporter_TraceClientDoesNotTrow_ExportResultSuccess()
 
         for (int i = 0; i < 10; i++)
         {
-            using Activity activity = source.StartActivity("Test Activity");
+            using Activity activity = CreateTestActivity();
             processor.OnEnd(activity);
         }
 
@@ -192,6 +192,7 @@ internal static Activity CreateTestActivity(
             { "doubleKey", 1D },
             { "doubleKey2", 1F },
             { "boolKey", true },
+            { "nullKey", null },
         };
         if (additionalAttributes != null)
         {
@@ -224,7 +225,7 @@ internal static Activity CreateTestActivity(
         var activitySource = new ActivitySource(nameof(CreateTestActivity));
 
         var tags = setAttributes ?
-            attributes.Select(kvp => new KeyValuePair<string, object>(kvp.Key, kvp.Value.ToString()))
+            attributes.Where(x => x.Value != null).Select(kvp => new KeyValuePair<string, object>(kvp.Key, kvp.Value.ToString()))
             : null;
         var links = addLinks ?
             new[]