Merge pull request #69927 from CyrusNajmabadi/asserts

Fix torn write of struct causing crash in symbol finder.
dotnet · Sep 13, 2023 · 0aec763 · 0aec763
2 parents 0d61377 + a8e8d41
commit 0aec763
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Showing 5 changed files with 286 additions and 306 deletions.
diff --git a/src/Workspaces/Core/Portable/FindSymbols/SymbolTree/SymbolTreeInfo.cs b/src/Workspaces/Core/Portable/FindSymbols/SymbolTree/SymbolTreeInfo.cs
@@ -3,16 +3,15 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
-using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Diagnostics;
 using System.Linq;
+using System.Runtime.CompilerServices;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.Collections;
 using Microsoft.CodeAnalysis.PooledObjects;
 using Microsoft.CodeAnalysis.Shared.Collections;
-using Microsoft.CodeAnalysis.Utilities;
 using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.FindSymbols
@@ -71,15 +70,6 @@ public MultiDictionary<string, ExtensionMethodInfo>.ValueSet GetExtensionMethodI
         public bool ContainsExtensionMethod => _receiverTypeNameToExtensionMethodMap?.Count > 0;
 
         private SpellChecker? _spellChecker;
-        private SpellChecker SpellChecker
-        {
-            get
-            {
-                _spellChecker ??= CreateSpellChecker(Checksum, _nodes);
-
-                return _spellChecker.Value;
-            }
-        }
 
         private SymbolTreeInfo(
             Checksum checksum,
@@ -181,11 +171,16 @@ private async Task<ImmutableArray<ISymbol>> FuzzyFindAsync(
             using var similarNames = TemporaryArray<string>.Empty;
             using var result = TemporaryArray<ISymbol>.Empty;
 
-            SpellChecker.FindSimilarWords(ref similarNames.AsRef(), name, substringsAreSimilar: false);
+            // Ensure the spell checker is initialized.  This is concurrency safe.  Technically multiple threads may end
+            // up overwriting the field, but even if that happens, we are sure to see a fully written spell checker as
+            // the runtime guarantees that the initialize of the SpellChecker instnace completely written when we read
+            // our field.
+            _spellChecker ??= CreateSpellChecker(Checksum, _nodes);
+            _spellChecker.FindSimilarWords(ref similarNames.AsRef(), name, substringsAreSimilar: false);
 
             foreach (var similarName in similarNames)
             {
-                var symbols = await FindAsync(lazyAssembly, similarName, ignoreCase: true, cancellationToken: cancellationToken).ConfigureAwait(false);
+                var symbols = await FindAsync(lazyAssembly, similarName, ignoreCase: true, cancellationToken).ConfigureAwait(false);
                 result.AddRange(symbols);
             }