fix(perf): Materialize trigger collections to eliminate ConcatIterator CPU waste

Replace IEnumerable<T> fields with List<T> to avoid deeply nested
ConcatIterator chains from repeated .Concat() calls. Each WithAdditionalTrigger
call now uses List.Add() instead. Also cache the service provider hash code,
use O(1) List.Count property instead of LINQ .Count(), and add count-based
fast paths in ShouldUseSameServiceProvider to short-circuit before SequenceEqual.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
(cherry picked from commit 0cc6aa1)

Author: 2 people

src/EntityFrameworkCore.Triggered/Infrastructure/Internal/TriggersOptionExtension.cs

@@ -17,6 +17,7 @@ public class TriggersOptionExtension : IDbContextOptionsExtension
         sealed class ExtensionInfo : DbContextOptionsExtensionInfo
         {
             private string? _logFragment;
+            private int? _serviceProviderHashCode;
             public ExtensionInfo(IDbContextOptionsExtension extension) : base(extension)
             {
             }
@@ -44,14 +45,19 @@ public override void PopulateDebugInfo(IDictionary<string, string> debugInfo)
                     throw new ArgumentNullException(nameof(debugInfo));
                 }
 
-                debugInfo["Triggers:TriggersCount"] = (Extension._triggers?.Count() ?? 0).ToString();
-                debugInfo["Triggers:TriggerTypesCount"] = (Extension._triggerTypes?.Count() ?? 0).ToString();
+                debugInfo["Triggers:TriggersCount"] = (Extension._triggers?.Count ?? 0).ToString();
+                debugInfo["Triggers:TriggerTypesCount"] = (Extension._triggerTypes?.Count ?? 0).ToString();
                 debugInfo["Triggers:MaxCascadeCycles"] = Extension._maxCascadeCycles.ToString();
                 debugInfo["Triggers:CascadeBehavior"] = Extension._cascadeBehavior.ToString();
             }
 
             public override int GetServiceProviderHashCode()
             {
+                if (_serviceProviderHashCode.HasValue)
+                {
+                    return _serviceProviderHashCode.Value;
+                }
+
                 var hashCode = new HashCode();
 
                 if (Extension._triggers != null)
@@ -78,28 +84,56 @@ public override int GetServiceProviderHashCode()
                     hashCode.Add(Extension._serviceProviderTransform);
                 }
 
-                return hashCode.ToHashCode();
+                _serviceProviderHashCode = hashCode.ToHashCode();
+                return _serviceProviderHashCode.Value;
             }
 
             public override bool ShouldUseSameServiceProvider(DbContextOptionsExtensionInfo other)
-                => other is ExtensionInfo otherInfo
-                    && Enumerable.SequenceEqual(Extension._triggers ?? Enumerable.Empty<ValueTuple<object, ServiceLifetime>>(), otherInfo.Extension._triggers ?? Enumerable.Empty<ValueTuple<object, ServiceLifetime>>())
-                    && Enumerable.SequenceEqual(Extension._triggerTypes ?? Enumerable.Empty<Type>(), otherInfo.Extension._triggerTypes ?? Enumerable.Empty<Type>())
-                    && Extension._maxCascadeCycles == otherInfo.Extension._maxCascadeCycles
-                    && Extension._cascadeBehavior == otherInfo.Extension._cascadeBehavior
-                    && Extension._serviceProviderTransform == otherInfo.Extension._serviceProviderTransform;
+            {
+                if (other is not ExtensionInfo otherInfo)
+                {
+                    return false;
+                }
+
+                // Check cheap scalar comparisons first
+                if (Extension._maxCascadeCycles != otherInfo.Extension._maxCascadeCycles
+                    || Extension._cascadeBehavior != otherInfo.Extension._cascadeBehavior
+                    || Extension._serviceProviderTransform != otherInfo.Extension._serviceProviderTransform)
+                {
+                    return false;
+                }
+
+                // Check list counts before doing full sequence comparison
+                var triggersCount = Extension._triggers?.Count ?? 0;
+                var otherTriggersCount = otherInfo.Extension._triggers?.Count ?? 0;
+                if (triggersCount != otherTriggersCount)
+                {
+                    return false;
+                }
+
+                var triggerTypesCount = Extension._triggerTypes?.Count ?? 0;
+                var otherTriggerTypesCount = otherInfo.Extension._triggerTypes?.Count ?? 0;
+                if (triggerTypesCount != otherTriggerTypesCount)
+                {
+                    return false;
+                }
+
+                // Full sequence comparison only when counts match
+                return Enumerable.SequenceEqual(Extension._triggers ?? Enumerable.Empty<ValueTuple<object, ServiceLifetime>>(), otherInfo.Extension._triggers ?? Enumerable.Empty<ValueTuple<object, ServiceLifetime>>())
+                    && Enumerable.SequenceEqual(Extension._triggerTypes ?? Enumerable.Empty<Type>(), otherInfo.Extension._triggerTypes ?? Enumerable.Empty<Type>());
+            }
         }
 
         private ExtensionInfo? _info;
-        private IEnumerable<(object typeOrInstance, ServiceLifetime lifetime)>? _triggers;
-        private IEnumerable<Type> _triggerTypes;
+        private List<(object typeOrInstance, ServiceLifetime lifetime)>? _triggers;
+        private List<Type> _triggerTypes;
         private int _maxCascadeCycles = 100;
         private CascadeBehavior _cascadeBehavior = CascadeBehavior.EntityAndType;
         private Func<IServiceProvider, IServiceProvider>? _serviceProviderTransform;
 
         public TriggersOptionExtension()
         {
-            _triggerTypes = new[] {
+            _triggerTypes = new List<Type> {
                 typeof(IBeforeSaveTrigger<>),
                 typeof(IBeforeSaveAsyncTrigger<>),
                 typeof(IAfterSaveTrigger<>),
@@ -125,10 +159,10 @@ public TriggersOptionExtension(TriggersOptionExtension copyFrom)
         {
             if (copyFrom._triggers != null)
             {
-                _triggers = copyFrom._triggers;
+                _triggers = new List<(object typeOrInstance, ServiceLifetime lifetime)>(copyFrom._triggers);
             }
 
-            _triggerTypes = copyFrom._triggerTypes;
+            _triggerTypes = new List<Type>(copyFrom._triggerTypes);
             _maxCascadeCycles = copyFrom._maxCascadeCycles;
             _cascadeBehavior = copyFrom._cascadeBehavior;
             _serviceProviderTransform = copyFrom._serviceProviderTransform;
@@ -263,17 +297,8 @@ public TriggersOptionExtension WithAdditionalTrigger(Type triggerType, ServiceLi
             }
 
             var clone = Clone();
-            var triggerEnumerable = Enumerable.Repeat(((object)triggerType, lifetime), 1);
-
-            if (clone._triggers == null)
-            {
-                clone._triggers = triggerEnumerable;
-            }
-            else
-            {
-                clone._triggers = clone._triggers.Concat(triggerEnumerable);
-            }
-
+            clone._triggers ??= new List<(object typeOrInstance, ServiceLifetime lifetime)>();
+            clone._triggers.Add(((object)triggerType, lifetime));
 
             return clone;
         }
@@ -291,17 +316,8 @@ public TriggersOptionExtension WithAdditionalTrigger(object instance)
             }
 
             var clone = Clone();
-            var triggersEnumerable = Enumerable.Repeat((instance, ServiceLifetime.Singleton), 1);
-
-            if (clone._triggers == null)
-            {
-                clone._triggers = triggersEnumerable;
-            }
-            else
-            {
-                clone._triggers = clone._triggers.Concat(triggersEnumerable);
-            }
-
+            clone._triggers ??= new List<(object typeOrInstance, ServiceLifetime lifetime)>();
+            clone._triggers.Add((instance, ServiceLifetime.Singleton));
 
             return clone;
         }
@@ -313,19 +329,9 @@ public TriggersOptionExtension WithAdditionalTriggerType(Type triggerType)
                 throw new ArgumentNullException(nameof(triggerType));
             }
 
-
             var clone = Clone();
-            var triggerTypesEnumerable = Enumerable.Repeat(triggerType, 1);
-
-            if (clone._triggerTypes == null)
-            {
-                clone._triggerTypes = triggerTypesEnumerable;
-            }
-            else
-            {
-                clone._triggerTypes = clone._triggerTypes.Concat(triggerTypesEnumerable);
-            }
-
+            clone._triggerTypes ??= new List<Type>();
+            clone._triggerTypes.Add(triggerType);
 
             return clone;
         }