The BuilderName and StrategyName now defaults to null

src/Polly.Core.Tests/CircuitBreaker/AdvancedCircuitBreakerOptionsTests.cs

@@ -21,7 +21,7 @@ public void Ctor_Defaults()
         options.OnHalfOpened.Should().BeNull();
         options.ShouldHandle.Should().BeNull();
         options.StrategyType.Should().Be("CircuitBreaker");
-        options.StrategyName.Should().BeEmpty();
+        options.StrategyName.Should().BeNull();
 
         // now set to min values
         options.FailureThreshold = 0.001;
@@ -47,7 +47,7 @@ public void Ctor_Generic_Defaults()
         options.OnHalfOpened.Should().BeNull();
         options.ShouldHandle.Should().BeNull();
         options.StrategyType.Should().Be("CircuitBreaker");
-        options.StrategyName.Should().BeEmpty();
+        options.StrategyName.Should().BeNull();
 
         // now set to min values
         options.FailureThreshold = 0.001;

src/Polly.Core.Tests/CircuitBreaker/SimpleCircuitBreakerOptionsTests.cs

@@ -20,7 +20,7 @@ public void Ctor_Defaults()
         options.OnHalfOpened.Should().BeNull();
         options.ShouldHandle.Should().BeNull();
         options.StrategyType.Should().Be("CircuitBreaker");
-        options.StrategyName.Should().BeEmpty();
+        options.StrategyName.Should().BeNull();
 
         // now set to min values
         options.FailureThreshold = 1;
@@ -42,7 +42,7 @@ public void Ctor_Generic_Defaults()
         options.OnHalfOpened.Should().BeNull();
         options.ShouldHandle.Should().BeNull();
         options.StrategyType.Should().Be("CircuitBreaker");
-        options.StrategyName.Should().BeEmpty();
+        options.StrategyName.Should().BeNull();
 
         // now set to min values
         options.FailureThreshold = 1;

src/Polly.Core.Tests/GenericResilienceStrategyBuilderTests.cs

@@ -11,7 +11,7 @@ public class GenericResilienceStrategyBuilderTests
     [Fact]
     public void Ctor_EnsureDefaults()
     {
-        _builder.BuilderName.Should().Be("");
+        _builder.BuilderName.Should().BeNull();
         _builder.Properties.Should().NotBeNull();
         _builder.TimeProvider.Should().Be(TimeProvider.System);
         _builder.OnCreatingStrategy.Should().BeNull();

src/Polly.Core.Tests/ResilienceStrategyBuilderTests.cs

@@ -12,7 +12,7 @@ public void Ctor_EnsureDefaults()
     {
         var builder = new ResilienceStrategyBuilder();
 
-        builder.BuilderName.Should().Be("");
+        builder.BuilderName.Should().BeNull();
         builder.Properties.Should().NotBeNull();
         builder.TimeProvider.Should().Be(TimeProvider.System);
         builder.IsGenericBuilder.Should().BeFalse();
@@ -157,20 +157,17 @@ public void AddStrategy_AfterUsed_Throws()
     [Fact]
     public void Build_InvalidBuilderOptions_Throw()
     {
-        var builder = new ResilienceStrategyBuilder
-        {
-            BuilderName = null!
-        };
+        var builder = new InvalidResilienceStrategyBuilder();
 
-        builder.Invoking(b => b.Build())
+        builder.Invoking(b => b.BuildStrategy())
             .Should()
             .Throw<ValidationException>()
             .WithMessage(
 """
 The 'ResilienceStrategyBuilder' configuration is invalid.
 
 Validation Errors:
-The BuilderName field is required.
+The RequiredProperty field is required.
 """);
     }
 
@@ -180,15 +177,15 @@ public void AddStrategy_InvalidOptions_Throws()
         var builder = new ResilienceStrategyBuilder();
 
         builder
-            .Invoking(b => b.AddStrategy(_ => NullResilienceStrategy.Instance, new TestResilienceStrategyOptions { StrategyName = null! }))
+            .Invoking(b => b.AddStrategy(_ => NullResilienceStrategy.Instance, new InvalidResilienceStrategyOptions()))
             .Should()
             .Throw<ValidationException>()
             .WithMessage(
 """
 The 'ResilienceStrategyOptions' options are not valid.
 
 Validation Errors:
-The StrategyName field is required.
+The RequiredProperty field is required.
 """);
     }
 
@@ -344,4 +341,20 @@ protected internal override async ValueTask<Outcome<TResult>> ExecuteCoreAsync<T
             }
         }
     }
+
+    private class InvalidResilienceStrategyOptions : ResilienceStrategyOptions
+    {
+        [Required]
+        public string? RequiredProperty { get; set; }
+
+        public override string StrategyType => "Invalid";
+    }
+
+    private class InvalidResilienceStrategyBuilder : ResilienceStrategyBuilderBase
+    {
+        [Required]
+        public string? RequiredProperty { get; set; }
+
+        internal override bool IsGenericBuilder => false;
+    }
 }

src/Polly.Core.Tests/Strategy/ResilienceStrategyOptionsTests.cs

@@ -10,6 +10,6 @@ public void Ctor_EnsureDefaults()
         var options = new TestResilienceStrategyOptions();
 
         options.StrategyType.Should().Be("Test");
-        options.StrategyName.Should().Be("");
+        options.StrategyName.Should().BeNull();
     }
 }

src/Polly.Core/Strategy/ResilienceStrategyBuilderBase.cs

@@ -31,9 +31,11 @@ private protected ResilienceStrategyBuilderBase(ResilienceStrategyBuilderBase ot
     /// <summary>
     /// Gets or sets the name of the builder.
     /// </summary>
-    /// <remarks>This property is also included in the telemetry that is produced by the individual resilience strategies.</remarks>
-    [Required(AllowEmptyStrings = true)]
-    public string BuilderName { get; set; } = string.Empty;
+    /// <remarks>
+    /// This property is also included in the telemetry that is produced by the individual resilience strategies.
+    /// Defaults to <see langword="null"/>.
+    /// </remarks>
+    public string? BuilderName { get; set; }
 
     /// <summary>
     /// Gets the custom properties attached to builder options.

src/Polly.Core/Strategy/ResilienceStrategyBuilderContext.cs

@@ -9,9 +9,9 @@ namespace Polly.Strategy;
 public sealed class ResilienceStrategyBuilderContext
 {
     internal ResilienceStrategyBuilderContext(
-        string builderName,
+        string? builderName,
         ResilienceProperties builderProperties,
-        string strategyName,
+        string? strategyName,
         string strategyType,
         TimeProvider timeProvider,
         bool isGenericBuilder)
@@ -28,7 +28,7 @@ internal ResilienceStrategyBuilderContext(
     /// <summary>
     /// Gets the name of the builder.
     /// </summary>
-    public string BuilderName { get; }
+    public string? BuilderName { get; }
 
     /// <summary>
     /// Gets the custom properties attached to the builder.
@@ -38,7 +38,7 @@ internal ResilienceStrategyBuilderContext(
     /// <summary>
     /// Gets the name of the strategy.
     /// </summary>
-    public string StrategyName { get; }
+    public string? StrategyName { get; }
 
     /// <summary>
     /// Gets the type of the strategy.

src/Polly.Core/Strategy/ResilienceStrategyOptions.cs

@@ -1,5 +1,3 @@
-using System.ComponentModel.DataAnnotations;
-
 namespace Polly.Strategy;
 
 /// <summary>
@@ -12,10 +10,9 @@ public abstract class ResilienceStrategyOptions
     /// </summary>
     /// <remarks>
     /// This property is also included in the telemetry that is produced by the individual resilience strategies.
-    /// Defaults to <see cref="string.Empty"/>. This name uniquely identifies particular instance of specific strategy.
+    /// Defaults to <see langword="null"/>. This name uniquely identifies particular instance of specific strategy.
     /// </remarks>
-    [Required(AllowEmptyStrings = true)]
-    public string StrategyName { get; set; } = string.Empty;
+    public string? StrategyName { get; set; }
 
     /// <summary>
     /// Gets the strategy type.

src/Polly.Core/Telemetry/ResilienceTelemetrySource.cs

@@ -1,4 +1,4 @@
 namespace Polly.Telemetry;
 
-internal sealed record class ResilienceTelemetrySource(string BuilderName, ResilienceProperties BuilderProperties, string StrategyName, string StrategyType);
+internal sealed record class ResilienceTelemetrySource(string? BuilderName, ResilienceProperties BuilderProperties, string? StrategyName, string StrategyType);
 

src/Polly.Core/Telemetry/TelemetryUtil.cs

@@ -10,7 +10,7 @@ internal static class TelemetryUtil
 
     internal static readonly ResiliencePropertyKey<string> StrategyKey = new("StrategyKey");
 
-    public static ResilienceStrategyTelemetry CreateTelemetry(string builderName, ResilienceProperties builderProperties, string strategyName, string strategyType)
+    public static ResilienceStrategyTelemetry CreateTelemetry(string? builderName, ResilienceProperties builderProperties, string? strategyName, string strategyType)
     {
         builderProperties.TryGetValue(DiagnosticSourceKey, out var diagnosticSource);
 

src/Polly.Extensions/Telemetry/Log.cs

@@ -38,21 +38,21 @@ internal static class Log
     public static partial void ResilienceEvent(
         this ILogger logger,
         string eventName,
-        string builderName,
-        string strategyName,
+        string? builderName,
+        string? strategyName,
         string strategyType,
         string? strategyKey,
         object? result,
         Exception? exception);
 #else
-    private static readonly Action<ILogger, string, string, string, string, string?, object?, Exception?> ResilienceEventAction =
-        LoggerMessage.Define<string, string, string, string, string?, object?>(LogLevel.Warning, new EventId(0, "ResilienceEvent"), ResilienceEventMessage);
+    private static readonly Action<ILogger, string, string?, string?, string, string?, object?, Exception?> ResilienceEventAction =
+        LoggerMessage.Define<string, string?, string?, string, string?, object?>(LogLevel.Warning, new EventId(0, "ResilienceEvent"), ResilienceEventMessage);
 
     public static void ResilienceEvent(
         this ILogger logger,
         string eventName,
-        string builderName,
-        string strategyName,
+        string? builderName,
+        string? strategyName,
         string strategyType,
         string? strategyKey,
         object? result,
@@ -66,16 +66,16 @@ public static void ResilienceEvent(
     [LoggerMessage(1, LogLevel.Debug, StrategyExecutingMessage, EventName = "StrategyExecuting")]
     public static partial void ExecutingStrategy(
         this ILogger logger,
-        string builderName,
+        string? builderName,
         string? strategyKey,
         string resultType);
 #else
-    private static readonly Action<ILogger, string, string?, string, Exception?> ExecutingStrategyAction =
-        LoggerMessage.Define<string, string?, string>(LogLevel.Debug, new EventId(1, "StrategyExecuting"), StrategyExecutingMessage);
+    private static readonly Action<ILogger, string?, string?, string, Exception?> ExecutingStrategyAction =
+        LoggerMessage.Define<string?, string?, string>(LogLevel.Debug, new EventId(1, "StrategyExecuting"), StrategyExecutingMessage);
 
     public static void ExecutingStrategy(
         this ILogger logger,
-        string builderName,
+        string? builderName,
         string? strategyKey,
         string resultType)
     {
@@ -87,20 +87,20 @@ public static void ExecutingStrategy(
     [LoggerMessage(2, LogLevel.Debug, StrategyExecutedMessage, EventName = "StrategyExecuted")]
     public static partial void StrategyExecuted(
         this ILogger logger,
-        string builderName,
+        string? builderName,
         string? strategyKey,
         string resultType,
         object? result,
         string executionHealth,
         double executionTime,
         Exception? exception);
 #else
-    private static readonly Action<ILogger, string, string?, string, object?, string, double, Exception?> StrategyExecutedAction =
-        LoggerMessage.Define<string, string?, string, object?, string, double>(LogLevel.Debug, new EventId(2, "StrategyExecuted"), StrategyExecutedMessage);
+    private static readonly Action<ILogger, string?, string?, string, object?, string, double, Exception?> StrategyExecutedAction =
+        LoggerMessage.Define<string?, string?, string, object?, string, double>(LogLevel.Debug, new EventId(2, "StrategyExecuted"), StrategyExecutedMessage);
 
     public static void StrategyExecuted(
         this ILogger logger,
-        string builderName,
+        string? builderName,
         string? strategyKey,
         string resultType,
         object? result,

src/Polly.Extensions/Telemetry/TelemetryResilienceStrategy.cs

@@ -11,7 +11,7 @@ namespace Polly.Extensions.Telemetry;
 internal sealed class TelemetryResilienceStrategy : ResilienceStrategy
 {
     private readonly TimeProvider _timeProvider;
-    private readonly string _builderName;
+    private readonly string? _builderName;
     private readonly string? _strategyKey;
     private readonly List<Action<EnrichmentContext>> _enrichers;
     private readonly ILogger _logger;
@@ -28,7 +28,7 @@ public TelemetryResilienceStrategy(
 
     public TelemetryResilienceStrategy(
         TimeProvider timeProvider,
-        string builderName,
+        string? builderName,
         string? strategyKey,
         ILoggerFactory loggerFactory,
         List<Action<EnrichmentContext>> enrichers)