Rename RootSpan to FirstSpan

Author: andrewlock

tracer/src/Datadog.Trace/Agent/AgentWriter.cs

@@ -1,4 +1,4 @@
-// <copyright file="AgentWriter.cs" company="Datadog">
+// <copyright file="AgentWriter.cs" company="Datadog">
 // Unless explicitly stated otherwise all files in this repository are licensed under the Apache 2 License.
 // This product includes software developed at Datadog (https://www.datadoghq.com/). Copyright 2017 Datadog, Inc.
 // </copyright>
@@ -483,7 +483,7 @@ private void SerializeTrace(in SpanCollection spans)
             }
 
             // Add the current keep rate to trace
-            if (chunk.RootSpan?.Context.TraceContext is { } trace)
+            if (chunk.FirstSpan?.Context.TraceContext is { } trace)
             {
                 trace.TracesKeepRate = _traceKeepRateCalculator.GetKeepRate();
             }

tracer/src/Datadog.Trace/Agent/SpanCollection.cs

@@ -64,7 +64,7 @@ internal SpanCollection(Span[] values)
     /// <summary>
     /// Gets the first span in the <see cref="SpanCollection" />, or returns null if the collection is empty
     /// </summary>
-    public Span? RootSpan
+    public Span? FirstSpan
     {
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         get

tracer/src/Datadog.Trace/Ci/Processors/OriginTagTraceProcessor.cs

@@ -1,4 +1,4 @@
-// <copyright file="OriginTagTraceProcessor.cs" company="Datadog">
+// <copyright file="OriginTagTraceProcessor.cs" company="Datadog">
 // Unless explicitly stated otherwise all files in this repository are licensed under the Apache 2 License.
 // This product includes software developed at Datadog (https://www.datadoghq.com/). Copyright 2017 Datadog, Inc.
 // </copyright>
@@ -74,7 +74,7 @@ public SpanCollection Process(in SpanCollection trace)
             if (!_isCiVisibilityProtocol)
             {
                 // Sets the origin tag on the TraceContext to ensure the CI track.
-                var traceContext = trace.RootSpan?.Context.TraceContext;
+                var traceContext = trace.FirstSpan?.Context.TraceContext;
 
                 if (traceContext is not null)
                 {

tracer/src/Datadog.Trace/Processors/NormalizerTraceProcessor.cs

@@ -1,4 +1,4 @@
-// <copyright file="NormalizerTraceProcessor.cs" company="Datadog">
+// <copyright file="NormalizerTraceProcessor.cs" company="Datadog">
 // Unless explicitly stated otherwise all files in this repository are licensed under the Apache 2 License.
 // This product includes software developed at Datadog (https://www.datadoghq.com/). Copyright 2017 Datadog, Inc.
 // </copyright>
@@ -58,7 +58,7 @@ public SpanCollection Process(in SpanCollection trace)
             }
 
             // https://github.com/DataDog/datadog-agent/blob/eac2327c5574da7f225f9ef0f89eaeb05ed10382/pkg/trace/agent/normalizer.go#L133-L135
-            var traceContext = trace.RootSpan?.Context.TraceContext;
+            var traceContext = trace.FirstSpan?.Context.TraceContext;
 
             if (!string.IsNullOrEmpty(traceContext?.Environment))
             {

tracer/src/Datadog.Trace/TraceContext.cs

@@ -1,4 +1,4 @@
-// <copyright file="TraceContext.cs" company="Datadog">
+// <copyright file="TraceContext.cs" company="Datadog">
 // Unless explicitly stated otherwise all files in this repository are licensed under the Apache 2 License.
 // This product includes software developed at Datadog (https://www.datadoghq.com/). Copyright 2017 Datadog, Inc.
 // </copyright>
@@ -127,7 +127,7 @@ internal AppSecRequestContext AppSecRequestContext
         internal bool WafExecuted { get; set; }
 
         internal static TraceContext? GetTraceContext(in SpanCollection spans)
-            => spans.RootSpan?.Context.TraceContext;
+            => spans.FirstSpan?.Context.TraceContext;
 
         internal void EnableIastInRequest()
         {

tracer/test/Datadog.Trace.Tests/Agent/SpanCollectionTests.cs

@@ -19,7 +19,7 @@ public void DefaultValue()
         SpanCollection collection = default;
 
         collection.Count.Should().Be(0);
-        collection.RootSpan.Should().BeNull();
+        collection.FirstSpan.Should().BeNull();
         collection.ToArray().Array.Should().BeEmpty();
         foreach (var span in collection)
         {
@@ -36,7 +36,7 @@ public void SingleSpanConstructor()
         var collection = new SpanCollection(span);
 
         collection.Count.Should().Be(1);
-        collection.RootSpan.Should().BeSameAs(span);
+        collection.FirstSpan.Should().BeSameAs(span);
         collection.ToArray().Array.Should().ContainSingle().Which.Should().BeSameAs(span);
         var spans = new List<Span>();
         foreach (var x in collection)
@@ -56,7 +56,7 @@ public void ArrayCapacityConstructor()
         var collection = new SpanCollection(length);
 
         collection.Count.Should().Be(0);
-        collection.RootSpan.Should().BeNull();
+        collection.FirstSpan.Should().BeNull();
         var array = collection.ToArray();
         array.Count.Should().Be(0);
         array.Offset.Should().Be(0);
@@ -76,7 +76,7 @@ public void ArrayConstructor()
         var collection = new SpanCollection(spans, 2);
 
         collection.Count.Should().Be(2);
-        collection.RootSpan.Should().BeSameAs(spans[0]);
+        collection.FirstSpan.Should().BeSameAs(spans[0]);
         collection[0].Should().BeSameAs(spans[0]);
         collection[1].Should().BeSameAs(spans[1]);
         FluentActions.Invoking(() => collection[2]).Should().Throw<IndexOutOfRangeException>();
@@ -104,7 +104,7 @@ public void ArrayConstructor_SetsCountToArrayLength()
         var collection = new SpanCollection(spans);
 
         collection.Count.Should().Be(2);
-        collection.RootSpan.Should().BeSameAs(spans[0]);
+        collection.FirstSpan.Should().BeSameAs(spans[0]);
         collection[0].Should().BeSameAs(spans[0]);
         collection[1].Should().BeSameAs(spans[1]);
     }
@@ -118,7 +118,7 @@ public void Append_ToEmptyCollection()
         var result = SpanCollection.Append(in collection, span);
 
         result.Count.Should().Be(1);
-        result.RootSpan.Should().BeSameAs(span);
+        result.FirstSpan.Should().BeSameAs(span);
         result[0].Should().BeSameAs(span);
     }
 
@@ -132,7 +132,7 @@ public void Append_ToSingleSpanCollection()
         var result = SpanCollection.Append(in collection, span2);
 
         result.Count.Should().Be(2);
-        result.RootSpan.Should().BeSameAs(span1);
+        result.FirstSpan.Should().BeSameAs(span1);
         result[0].Should().BeSameAs(span1);
         result[1].Should().BeSameAs(span2);