Minor ResiliencePipelineRegistry cleanup of internals

Author: martintmk

src/LegacySupport/ConcurrentDictionaryExtensions.cs

@@ -0,0 +1,16 @@
+namespace System.Collections.Concurrent;
+
+#if !NETCOREAPP
+internal static class ConcurrentDictionaryExtensions
+{
+    public static TValue GetOrAdd<TKey, TValue, TArg>(this ConcurrentDictionary<TKey, TValue> dictionary, TKey key, Func<TKey, TArg, TValue> valueFactory, TArg factoryArgument)
+    {
+        if (dictionary.TryGetValue(key, out TValue value))
+        {
+            return value;
+        }
+
+        return dictionary.GetOrAdd(key, valueFactory(key, factoryArgument));
+    }
+}
+#endif

src/Polly.Core/Registry/ResiliencePipelineRegistry.TResult.cs

@@ -9,7 +9,7 @@ private sealed class GenericRegistry<TResult> : IDisposable, IAsyncDisposable
     {
         private readonly Func<ResiliencePipelineBuilder<TResult>> _activator;
         private readonly ConcurrentDictionary<TKey, Action<ResiliencePipelineBuilder<TResult>, ConfigureBuilderContext<TKey>>> _builders;
-        private readonly ConcurrentDictionary<TKey, ResiliencePipeline<TResult>> _strategies;
+        private readonly ConcurrentDictionary<TKey, ResiliencePipeline<TResult>> _pipelines;
 
         private readonly Func<TKey, string> _builderNameFormatter;
         private readonly Func<TKey, string>? _instanceNameFormatter;
@@ -23,14 +23,14 @@ public GenericRegistry(
         {
             _activator = activator;
             _builders = new ConcurrentDictionary<TKey, Action<ResiliencePipelineBuilder<TResult>, ConfigureBuilderContext<TKey>>>(builderComparer);
-            _strategies = new ConcurrentDictionary<TKey, ResiliencePipeline<TResult>>(strategyComparer);
+            _pipelines = new ConcurrentDictionary<TKey, ResiliencePipeline<TResult>>(strategyComparer);
             _builderNameFormatter = builderNameFormatter;
             _instanceNameFormatter = instanceNameFormatter;
         }
 
         public bool TryGet(TKey key, [NotNullWhen(true)] out ResiliencePipeline<TResult>? strategy)
         {
-            if (_strategies.TryGetValue(key, out strategy))
+            if (_pipelines.TryGetValue(key, out strategy))
             {
                 return true;
             }
@@ -49,37 +49,35 @@ public ResiliencePipeline<TResult> GetOrAdd(TKey key, Action<ResiliencePipelineB
         {
             var context = new ConfigureBuilderContext<TKey>(key, _builderNameFormatter(key), _instanceNameFormatter?.Invoke(key));
 
-#if NETCOREAPP3_0_OR_GREATER
-            return _strategies.GetOrAdd(key, static (_, factory) =>
+            return _pipelines.GetOrAdd(key, static (_, factory) =>
             {
-                return new ResiliencePipeline<TResult>(CreatePipelineComponent(factory.instance._activator, factory.context, factory.configure), DisposeBehavior.Reject);
+                var component = CreatePipelineComponent(factory.instance._activator, factory.context, factory.configure);
+
+                return new ResiliencePipeline<TResult>(component, DisposeBehavior.Reject);
             },
             (instance: this, context, configure));
-#else
-            return _strategies.GetOrAdd(key, _ => new ResiliencePipeline<TResult>(CreatePipelineComponent(_activator, context, configure), DisposeBehavior.Reject));
-#endif
         }
 
         public bool TryAddBuilder(TKey key, Action<ResiliencePipelineBuilder<TResult>, ConfigureBuilderContext<TKey>> configure) => _builders.TryAdd(key, configure);
 
         public void Dispose()
         {
-            foreach (var strategy in _strategies.Values)
+            foreach (var strategy in _pipelines.Values)
             {
                 strategy.DisposeHelper.ForceDispose();
             }
 
-            _strategies.Clear();
+            _pipelines.Clear();
         }
 
         public async ValueTask DisposeAsync()
         {
-            foreach (var strategy in _strategies.Values)
+            foreach (var strategy in _pipelines.Values)
             {
                 await strategy.DisposeHelper.ForceDisposeAsync().ConfigureAwait(false);
             }
 
-            _strategies.Clear();
+            _pipelines.Clear();
         }
     }
 }

src/Polly.Core/Registry/ResiliencePipelineRegistry.cs

@@ -126,15 +126,13 @@ public ResiliencePipeline GetOrAddPipeline(TKey key, Action<ResiliencePipelineBu
 
         var context = new ConfigureBuilderContext<TKey>(key, _builderNameFormatter(key), _instanceNameFormatter?.Invoke(key));
 
-#if NETCOREAPP3_0_OR_GREATER
         return _pipelines.GetOrAdd(key, static (_, factory) =>
         {
-            return new ResiliencePipeline(CreatePipelineComponent(factory.instance._activator, factory.context, factory.configure), DisposeBehavior.Reject);
+            var component = CreatePipelineComponent(factory.instance._activator, factory.context, factory.configure);
+
+            return new ResiliencePipeline(component, DisposeBehavior.Reject);
         },
         (instance: this, context, configure));
-#else
-        return _pipelines.GetOrAdd(key, _ => new ResiliencePipeline(CreatePipelineComponent(_activator, context, configure), DisposeBehavior.Reject));
-#endif
     }
 
     /// <summary>