[Instrumentation.AspNet] Fix analysis warnings

src/OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModule/TelemetryHttpModule.cs

@@ -18,6 +18,7 @@
 using System.Diagnostics;
 using System.Reflection;
 using System.Web;
+using OpenTelemetry.Internal;
 
 namespace OpenTelemetry.Instrumentation.AspNet;
 
@@ -57,6 +58,8 @@ public void Dispose()
     /// <inheritdoc />
     public void Init(HttpApplication context)
     {
+        Guard.ThrowIfNull(context);
+
         context.BeginRequest += this.Application_BeginRequest;
         context.EndRequest += this.Application_EndRequest;
         context.Error += this.Application_Error;

src/OpenTelemetry.Instrumentation.AspNet/MeterProviderBuilderExtensions.cs

@@ -34,8 +34,7 @@ public static MeterProviderBuilder AddAspNetInstrumentation(
     {
         Guard.ThrowIfNull(builder);
 
-        var instrumentation = new AspNetMetrics();
         builder.AddMeter(AspNetMetrics.InstrumentationName);
-        return builder.AddInstrumentation(() => instrumentation);
+        return builder.AddInstrumentation(() => new AspNetMetrics());
     }
 }

test/OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModule.Tests/ActivityHelperTest.cs

@@ -429,7 +429,9 @@ public void Can_Create_RootActivity_And_Saved_In_HttContext()
     }
 
     [Fact]
+#pragma warning disable CA1030 // Use events where appropriate
     public void Fire_Exception_Events()
+#pragma warning restore CA1030 // Use events where appropriate
     {
         int callbacksFired = 0;
 
@@ -529,13 +531,11 @@ public TestHttpContext(Exception error = null)
 
     private class NoopTextMapPropagator : TextMapPropagator
     {
-        private static readonly PropagationContext DefaultPropagationContext = default;
-
         public override ISet<string> Fields => null;
 
         public override PropagationContext Extract<T>(PropagationContext context, T carrier, Func<T, string, IEnumerable<string>> getter)
         {
-            return DefaultPropagationContext;
+            return default;
         }
 
         public override void Inject<T>(PropagationContext context, T carrier, Action<T, string, string> setter)

test/OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModule.Tests/HttpContextHelper.cs

@@ -79,9 +79,9 @@ public override string[][] GetUnknownRequestHeaders()
 
         public override string GetUnknownRequestHeader(string name)
         {
-            if (this.headers.ContainsKey(name))
+            if (this.headers.TryGetValue(name, out var value))
             {
-                return this.headers[name];
+                return value;
             }
 
             return base.GetUnknownRequestHeader(name);
@@ -91,9 +91,9 @@ public override string GetKnownRequestHeader(int index)
         {
             var name = GetKnownRequestHeaderName(index);
 
-            if (this.headers.ContainsKey(name))
+            if (this.headers.TryGetValue(name, out var value))
             {
-                return this.headers[name];
+                return value;
             }
 
             return base.GetKnownRequestHeader(index);

test/OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModule.Tests/WebConfigTransformTest.cs

@@ -391,16 +391,17 @@ private XDocument ApplyTransformation(string originalConfiguration, string trans
             var document = new XmlTransformableDocument();
             using var transformation = new XmlTransformation(stream, null);
             stream = null;
+#pragma warning disable CA3075 // Insecure DTD processing in XML
             document.LoadXml(originalConfiguration);
+#pragma warning restore CA3075 // Insecure DTD processing in XML
             transformation.Apply(document);
             result = XDocument.Parse(document.OuterXml);
         }
         finally
         {
-            if (stream != null)
-            {
-                stream.Dispose();
-            }
+#pragma warning disable CA1508 // Avoid dead conditional code
+            stream?.Dispose();
+#pragma warning restore CA1508 // Avoid dead conditional code
         }
 
         return result;

test/OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModule.Tests/WebConfigWithLocationTagTransformTest.cs

@@ -421,16 +421,17 @@ private XDocument ApplyTransformation(string originalConfiguration, string trans
             var document = new XmlTransformableDocument();
             using var transformation = new XmlTransformation(stream, null);
             stream = null;
+#pragma warning disable CA3075 // Insecure DTD processing in XML
             document.LoadXml(originalConfiguration);
+#pragma warning restore CA3075 // Insecure DTD processing in XML
             transformation.Apply(document);
             result = XDocument.Parse(document.OuterXml);
         }
         finally
         {
-            if (stream != null)
-            {
-                stream.Dispose();
-            }
+#pragma warning disable CA1508 // Avoid dead conditional code
+            stream?.Dispose();
+#pragma warning restore CA1508 // Avoid dead conditional code
         }
 
         return result;