Move calculation of TagHelperCollector.MightContainTagHelpers into the cache

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/TagHelperCollector.Cache.cs

@@ -1,15 +1,19 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System;
+using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
+using System.Linq;
 using System.Threading;
+using Microsoft.CodeAnalysis;
 
 namespace Microsoft.AspNetCore.Razor.Language;
 
 public abstract partial class TagHelperCollector<T>
     where T : TagHelperCollector<T>
 {
-    private class Cache
+    private sealed class Cache(IAssemblySymbol assembly)
     {
         private const int IncludeDocumentation = 1 << 0;
         private const int ExcludeHidden = 1 << 1;
@@ -19,6 +23,8 @@ private class Cache
 
         private readonly TagHelperDescriptor[]?[] _tagHelpers = new TagHelperDescriptor[CacheSize][];
 
+        public bool MightContainTagHelpers { get; } = CalculateMightContainTagHelpers(assembly);
+
         public bool TryGet(bool includeDocumentation, bool excludeHidden, [NotNullWhen(true)] out TagHelperDescriptor[]? tagHelpers)
         {
             var index = CalculateIndex(includeDocumentation, excludeHidden);
@@ -50,5 +56,15 @@ private static int CalculateIndex(bool includeDocumentation, bool excludeHidden)
 
             return index;
         }
+
+        private static bool CalculateMightContainTagHelpers(IAssemblySymbol assembly)
+        {
+            // In order to contain tag helpers, components, or anything else we might want to find,
+            // the assembly must start with "Microsoft.AspNetCore." or reference an assembly that
+            // starts with "Microsoft.AspNetCore."
+            return assembly.Name.StartsWith("Microsoft.AspNetCore.", StringComparison.Ordinal) ||
+                    assembly.Modules.First().ReferencedAssemblies.Any(
+                        a => a.Name.StartsWith("Microsoft.AspNetCore.", StringComparison.Ordinal));
+        }
     }
 }

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/TagHelperCollector.cs

@@ -1,9 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System;
 using System.Collections.Generic;
-using System.Linq;
 using System.Runtime.CompilerServices;
 using Microsoft.AspNetCore.Razor.PooledObjects;
 using Microsoft.CodeAnalysis;
@@ -25,17 +23,6 @@ protected TagHelperCollector(Compilation compilation, ISymbol? targetSymbol)
         _targetSymbol = targetSymbol;
     }
 
-    private static bool MightContainTagHelpers(IAssemblySymbol assembly)
-    {
-        // In order to contain tag helpers, components, or anything else we might want to find,
-        // the assembly must start with "Microsoft.AspNetCore." or reference an assembly that
-        // starts with "Microsoft.AspNetCore."
-
-        return assembly.Name.StartsWith("Microsoft.AspNetCore.", StringComparison.Ordinal) ||
-               assembly.Modules.First().ReferencedAssemblies.Any(
-                   a => a.Name.StartsWith("Microsoft.AspNetCore.", StringComparison.Ordinal));
-    }
-
     protected abstract void Collect(ISymbol symbol, ICollection<TagHelperDescriptor> results);
 
     public void Collect(TagHelperDescriptorProviderContext context)
@@ -52,17 +39,17 @@ public void Collect(TagHelperDescriptorProviderContext context)
             {
                 if (_compilation.GetAssemblyOrModuleSymbol(reference) is IAssemblySymbol assembly)
                 {
-                    if (!MightContainTagHelpers(assembly))
-                    {
-                        continue;
-                    }
-
                     // Check to see if we already have tag helpers cached for this assembly
                     // and use the cached versions if we do. Roslyn shares PE assembly symbols
                     // across compilations, so this ensures that we don't produce new tag helpers
                     // for the same assemblies over and over again.
 
-                    var cache = s_perAssemblyCaches.GetOrCreateValue(assembly);
+                    var cache = s_perAssemblyCaches.GetValue(assembly, static assembly => new Cache(assembly));
+
+                    if (!cache.MightContainTagHelpers)
+                    {
+                        continue;
+                    }
 
                     var includeDocumentation = context.IncludeDocumentation;
                     var excludeHidden = context.ExcludeHidden;