Fix warnings and cleanup.

.publicApi/Microsoft.ApplicationInsights.dll/Stable/PublicAPI.Unshipped.txt

@@ -279,7 +279,7 @@ override Microsoft.ApplicationInsights.DataContracts.RequestTelemetry.Success.ge
 override Microsoft.ApplicationInsights.DataContracts.RequestTelemetry.Success.set -> void
 override Microsoft.ApplicationInsights.DataContracts.RequestTelemetry.Timestamp.get -> System.DateTimeOffset
 override Microsoft.ApplicationInsights.DataContracts.RequestTelemetry.Timestamp.set -> void
-override Microsoft.ApplicationInsights.Metrics.MetricIdentifier.Equals(object otherObj) -> bool
+override Microsoft.ApplicationInsights.Metrics.MetricIdentifier.Equals(object obj) -> bool
 override Microsoft.ApplicationInsights.Metrics.MetricIdentifier.GetHashCode() -> int
 override Microsoft.ApplicationInsights.Metrics.MetricIdentifier.ToString() -> string
 static Microsoft.ApplicationInsights.Extensibility.TelemetryConfiguration.CreateDefault() -> Microsoft.ApplicationInsights.Extensibility.TelemetryConfiguration

BASE/src/Microsoft.ApplicationInsights/DataContracts/ExceptionTelemetry.cs

@@ -287,7 +287,9 @@ private static Exception ReconstructExceptionFromDetails(IReadOnlyList<Exception
                 }
 
                 // Create exception with inner if it exists
+#pragma warning disable CA2201 // Exception reconstruction requires generic Exception type
                 var exception = innerException != null ? new Exception(message, innerException) : new Exception(message);
+#pragma warning restore CA2201
                 exceptionDict[detail.Id] = exception;
             }
 

BASE/src/Microsoft.ApplicationInsights/Extensibility/Implementation/OperationHolder.cs

@@ -36,18 +36,8 @@ public OperationHolder(TelemetryClient telemetryClient, T telemetry, Activity ac
         /// <param name="suppressedActivity">An ambient activity that was suppressed to create a root operation and should be restored on dispose.</param>
         public OperationHolder(TelemetryClient telemetryClient, T telemetry, Activity activity, Activity suppressedActivity)
         {
-            if (telemetryClient == null)
-            {
-                throw new ArgumentNullException(nameof(telemetryClient));
-            }
-
-            if (telemetry == null)
-            {
-                throw new ArgumentNullException(nameof(telemetry));
-            }
-
-            this.telemetryClient = telemetryClient;
-            this.Telemetry = telemetry;
+            this.telemetryClient = telemetryClient ?? throw new ArgumentNullException(nameof(telemetryClient));
+            this.Telemetry = telemetry ?? throw new ArgumentNullException(nameof(telemetry));
             this.activity = activity;
             this.suppressedActivity = suppressedActivity;
         }

BASE/src/Microsoft.ApplicationInsights/Extensibility/Implementation/Tracing/SelfDiagnosticsConfigParser.cs

@@ -74,8 +74,14 @@ public bool TryGetConfiguration(out string logDirectory, out int fileSizeInKB, o
                         this.configBuffer = buffer;
                     }
 
-                    file.Read(buffer, 0, buffer.Length);
-                    string configJson = Encoding.UTF8.GetString(buffer);
+                    int totalBytesRead = 0;
+                    int bytesRead;
+                    while (totalBytesRead < buffer.Length && (bytesRead = file.Read(buffer, totalBytesRead, buffer.Length - totalBytesRead)) > 0)
+                    {
+                        totalBytesRead += bytesRead;
+                    }
+
+                    string configJson = Encoding.UTF8.GetString(buffer, 0, totalBytesRead);
 
                     if (logDirectory == null && !TryParseLogDirectory(configJson, out logDirectory))
                     {
@@ -102,7 +108,11 @@ public bool TryGetConfiguration(out string logDirectory, out int fileSizeInKB, o
                         return false;
                     }
 
+#if NETCOREAPP
+                    logLevel = Enum.Parse<EventLevel>(logLevelString);
+#else
                     logLevel = (EventLevel)Enum.Parse(typeof(EventLevel), logLevelString);
+#endif
                     return true;
                 }
             }

BASE/src/Microsoft.ApplicationInsights/Extensibility/TelemetryConfiguration.cs

@@ -256,11 +256,14 @@ public static TelemetryConfiguration CreateDefault()
         public void ConfigureOpenTelemetryBuilder(Action<IOpenTelemetryBuilder> configure)
         {
             this.ThrowIfBuilt();
-
+#if NET6_0_OR_GREATER
+            ArgumentNullException.ThrowIfNull(configure);
+#else
             if (configure == null)
             {
                 throw new ArgumentNullException(nameof(configure));
             }
+#endif
 
             // Chain the configurations
             var previousConfiguration = this.builderConfiguration;
@@ -291,11 +294,14 @@ public void Dispose()
         public void SetAzureTokenCredential(TokenCredential tokenCredential)
         {
             this.ThrowIfBuilt();
-
+#if NET6_0_OR_GREATER
+            ArgumentNullException.ThrowIfNull(tokenCredential);
+#else
             if (tokenCredential == null)
             {
                 throw new ArgumentNullException(nameof(tokenCredential));
             }
+#endif
 
             // Configure the OpenTelemetry builder to pass the credential to Azure Monitor Exporter
             this.ConfigureOpenTelemetryBuilder(builder =>

BASE/src/Microsoft.ApplicationInsights/Internal/FeatureMetricEmissionHelper.cs

@@ -123,7 +123,7 @@ private static Dictionary<string, object> GetVmMetadata()
                     using (var httpClient = new HttpClient() { Timeout = TimeSpan.FromSeconds(2) })
                     {
                         httpClient.DefaultRequestHeaders.Add("Metadata", "True");
-                        var responseString = httpClient.GetStringAsync(StatsbeatConstants.AMSUrl);
+                        var responseString = httpClient.GetStringAsync(new Uri(StatsbeatConstants.AMSUrl));
                         return JsonSerializer.Deserialize<Dictionary<string, object>>(responseString.Result);
                     }
                 }
@@ -168,7 +168,7 @@ private string GetResourceProvider()
                 if (vmMetadata.TryGetValue("osType", out var osType) && osType is string)
                 {
                     // osType takes precedence over the platform-observed OS.
-                    this.os = (osType as string).ToLower(CultureInfo.InvariantCulture);
+                    this.os = (osType as string).ToUpperInvariant();
                 }
                 else
                 {

BASE/src/Microsoft.ApplicationInsights/Metrics/MetricIdentifier.cs

@@ -1,6 +1,9 @@
 namespace Microsoft.ApplicationInsights.Metrics
 {
     using System;
+#if NET8_0_OR_GREATER
+    using System.Buffers;
+#endif
     using System.Collections.Generic;
     using System.Runtime.CompilerServices;
     using System.Text;
@@ -16,11 +19,20 @@ public sealed class MetricIdentifier : IEquatable<MetricIdentifier>
 
         private const string NoNamespaceIdentifierStringComponent = "<NoNamespace>";
 
+#if NET8_0_OR_GREATER
+        private static readonly SearchValues<char> InvalidMetricCharsSearchValues = SearchValues.Create(
+            new char[]
+            {
+                '\0', '"', '\'', '(', ')', '[', ']', '{', '}', '<', '>', '=', ',',
+                '`',  '~', '!',  '@', '#', '$', '%', '^', '&', '*', '+', '?',
+            });
+#else
         private static readonly char[] InvalidMetricChars = new char[]
             {
                         '\0', '"', '\'', '(', ')', '[', ']', '{', '}', '<', '>', '=', ',',
                         '`',  '~', '!',  '@', '#', '$', '%', '^', '&', '*', '+', '?',
             };
+#endif
 
         private static string defaultMetricNamespace = String.Empty;
 
@@ -65,7 +77,11 @@ private static void ValidateLiteral(string partValue, string partName, bool allo
                 }
             }
 
-            int pos = partName.IndexOfAny(InvalidMetricChars);
+#if NET8_0_OR_GREATER
+            int pos = partValue.AsSpan().IndexOfAny(InvalidMetricCharsSearchValues);
+#else
+            int pos = partValue.IndexOfAny(InvalidMetricChars);
+#endif
             if (pos >= 0)
             {
                 throw new ArgumentException(Invariant($"{partName} (\"{partValue}\") contains a disallowed character at position {pos}."));
@@ -501,17 +517,17 @@ public override int GetHashCode()
         /// Determines whether the specified object is a <c>MetricIdentifier</c> that is equal to this <c>MetricIdentifier</c> based on the
         /// respective metric namespaces, metric IDs and the number and the names of dimensions.
         /// </summary>
-        /// <param name="otherObj">Another object.</param>
+        /// <param name="obj">Another object.</param>
         /// <returns>Whether the specified other object is equal to this object based on the respective namespaces, IDs and dimension names.</returns>
-        public override bool Equals(object otherObj)
+        public override bool Equals(object obj)
         {
-            if (otherObj is MetricIdentifier otherMetricIdentifier)
+            if (obj is MetricIdentifier otherMetricIdentifier)
             {
                 return this.Equals(otherMetricIdentifier);
             }
             else
             {
-                return base.Equals(otherObj);
+                return base.Equals(obj);
             }
         }
 
@@ -617,7 +633,11 @@ private static void EnsureDimensionNameValid(ref int dimensionCount, ref string
                                            + " they must contain at least 1 printable character.");
             }
 
+#if NET8_0_OR_GREATER
+            int pos = dimensionName.AsSpan().IndexOfAny(InvalidMetricCharsSearchValues);
+#else
             int pos = dimensionName.IndexOfAny(InvalidMetricChars);
+#endif
             if (pos >= 0)
             {
                 throw new ArgumentException(Invariant($"Name for dimension number {thisDimensionNumber} (\"{dimensionName}\")")

BASE/src/Microsoft.ApplicationInsights/TelemetryClient.cs

@@ -473,7 +473,7 @@ public void TrackException(Exception exception, IDictionary<string, string> prop
             this.Configuration.FeatureReporter.MarkFeatureInUse(StatsbeatFeatures.TrackException);
             if (exception == null)
             {
-                exception = new Exception(Utils.PopulateRequiredStringValue(null, "message", typeof(ExceptionTelemetry).FullName));
+                exception = new InvalidOperationException(Utils.PopulateRequiredStringValue(null, "message", typeof(ExceptionTelemetry).FullName));
             }
 
             var state = new DictionaryLogState(this.Context, properties, exception.Message);
@@ -493,7 +493,7 @@ public void TrackException(ExceptionTelemetry telemetry)
             // TODO investigate how problem id, custom message, etc should appear in portal
             if (telemetry == null)
             {
-                var exception = new Exception(Utils.PopulateRequiredStringValue(null, "message", typeof(ExceptionTelemetry).FullName));
+                var exception = new InvalidOperationException(Utils.PopulateRequiredStringValue(null, "message", typeof(ExceptionTelemetry).FullName));
                 telemetry = new ExceptionTelemetry(exception);
             }
 
@@ -697,10 +697,14 @@ public void TrackDependency(DependencyTelemetry telemetry)
         [EditorBrowsable(EditorBrowsableState.Never)]
         public void Track(ITelemetry telemetry)
         {
+#if NET6_0_OR_GREATER
+            ArgumentNullException.ThrowIfNull(telemetry);
+#else
             if (telemetry == null)
             {
                 throw new ArgumentNullException(nameof(telemetry));
             }
+#endif
 
             switch (telemetry)
             {
@@ -1119,10 +1123,14 @@ public Metric GetMetric(
         public Metric GetMetric(
                             MetricIdentifier metricIdentifier)
         {
+#if NET6_0_OR_GREATER
+            ArgumentNullException.ThrowIfNull(metricIdentifier);
+#else
             if (metricIdentifier == null)
             {
                 throw new ArgumentNullException(nameof(metricIdentifier));
             }
+#endif
 
             // Build dimension names array from MetricIdentifier
             string[] dimensionNames = null;
@@ -1231,10 +1239,14 @@ private static ActivityKind GetActivityKindForDependency(string dependencyType)
         /// <returns>A reconstructed Exception with all diagnostic details.</returns>
         private static Exception ConvertToException(ExceptionTelemetry telemetry)
         {
+#if NET6_0_OR_GREATER
+            ArgumentNullException.ThrowIfNull(telemetry);
+#else
             if (telemetry == null)
             {
                 throw new ArgumentNullException(nameof(telemetry));
             }
+#endif
 
             Exception rootException = null;
 
@@ -1252,7 +1264,9 @@ private static Exception ConvertToException(ExceptionTelemetry telemetry)
             else
             {
                 // Fallback: create a generic exception with the message
+#pragma warning disable CA2201 // Exception reconstruction requires generic Exception type
                 rootException = new Exception(telemetry.Message ?? "<no message>");
+#pragma warning restore CA2201
             }
 
             // Enrich the exception with metadata
@@ -1270,7 +1284,9 @@ private static Exception ReconstructExceptionChain(IReadOnlyList<ExceptionDetail
         {
             if (exceptionDetailsList == null || exceptionDetailsList.Count == 0)
             {
+#pragma warning disable CA2201 // Exception reconstruction requires generic Exception type
                 return new Exception("<no exception details>");
+#pragma warning restore CA2201
             }
 
             // Process from innermost (index 0) to outermost (last index)
@@ -1287,6 +1303,7 @@ private static Exception ReconstructExceptionChain(IReadOnlyList<ExceptionDetail
                 // Include the type name in the message since we can't safely create typed exceptions via reflection
                 Exception currentException;
 
+#pragma warning disable CA2201 // Exception reconstruction requires generic Exception type
                 if (innerException != null)
                 {
                     currentException = new Exception($"[{typeName}] {message}", innerException);
@@ -1295,6 +1312,7 @@ private static Exception ReconstructExceptionChain(IReadOnlyList<ExceptionDetail
                 {
                     currentException = new Exception($"[{typeName}] {message}");
                 }
+#pragma warning restore CA2201
 
                 // Set the current exception as the inner for the next iteration
                 innerException = currentException;

BASE/src/Microsoft.ApplicationInsights/TelemetryClientExtensions.cs

@@ -53,10 +53,14 @@ public static IOperationHolder<T> StartOperation<T>(
      string parentOperationId = null)
      where T : OperationTelemetry, new()
         {
+#if NET6_0_OR_GREATER
+            ArgumentNullException.ThrowIfNull(telemetryClient);
+#else
             if (telemetryClient == null)
             {
                 throw new ArgumentNullException(nameof(telemetryClient));
             }
+#endif
 
             telemetryClient.Configuration.FeatureReporter.MarkFeatureInUse(Internal.StatsbeatFeatures.StartOperation);
 
@@ -137,6 +141,10 @@ public static IOperationHolder<T> StartOperation<T>(
             T operationTelemetry)
             where T : OperationTelemetry
         {
+#if NET6_0_OR_GREATER
+            ArgumentNullException.ThrowIfNull(telemetryClient);
+            ArgumentNullException.ThrowIfNull(operationTelemetry);
+#else
             if (telemetryClient == null)
             {
                 throw new ArgumentNullException(nameof(telemetryClient));
@@ -146,6 +154,7 @@ public static IOperationHolder<T> StartOperation<T>(
             {
                 throw new ArgumentNullException(nameof(operationTelemetry));
             }
+#endif
 
             if (string.IsNullOrEmpty(operationTelemetry.Name))
             {
@@ -221,10 +230,14 @@ public static IOperationHolder<T> StartOperation<T>(
             Activity activity)
             where T : OperationTelemetry, new()
         {
+#if NET6_0_OR_GREATER
+            ArgumentNullException.ThrowIfNull(telemetryClient);
+#else
             if (telemetryClient == null)
             {
                 throw new ArgumentNullException(nameof(telemetryClient));
             }
+#endif
 
             if (activity == null)
             {
@@ -275,10 +288,14 @@ public static void StopOperation<T>(
             IOperationHolder<T> operation)
             where T : OperationTelemetry
         {
+#if NET6_0_OR_GREATER
+            ArgumentNullException.ThrowIfNull(telemetryClient);
+#else
             if (telemetryClient == null)
             {
                 throw new ArgumentNullException(nameof(telemetryClient));
             }
+#endif
 
             if (operation == null)
             {