Go back to explicit lock usage

Author: ToddGrun

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

@@ -24,7 +24,7 @@ public sealed partial class RazorCodeDocument
     public RazorFileKind FileKind => ParserOptions.FileKind;
 
     private readonly PropertyTable _properties = new();
-    private readonly Lazy<RazorHtmlDocument> _lazyHtmlDocument;
+    private readonly object _htmlDocumentLock = new();
 
     private RazorCodeDocument(
         RazorSourceDocument source,
@@ -40,7 +40,6 @@ private RazorCodeDocument(
         CodeGenerationOptions = codeGenerationOptions ?? RazorCodeGenerationOptions.Default;
 
         _properties = properties ?? new();
-        _lazyHtmlDocument = new(() => CreateHtmlDocument());
     }
 
     public static RazorCodeDocument Create(
@@ -178,17 +177,20 @@ internal void SetCSharpDocument(RazorCSharpDocument value)
     }
 
     internal RazorHtmlDocument GetHtmlDocument()
-        => _lazyHtmlDocument.Value;
-
-    private RazorHtmlDocument CreateHtmlDocument()
     {
         if (_properties.HtmlDocument.TryGetValue(out var result))
         {
             return result;
         }
 
-        result = RazorHtmlWriter.GetHtmlDocument(this);
-        _properties.HtmlDocument.SetValue(result);
+        lock (_htmlDocumentLock)
+        {
+            if (!_properties.HtmlDocument.TryGetValue(out result))
+            {
+                result = RazorHtmlWriter.GetHtmlDocument(this);
+                _properties.HtmlDocument.SetValue(result);
+            }
+        }
 
         return result;
     }