Replace TryGetValue/TryRemove by a single TryRemove call to avoid potential issues with concurrent cache removal/addition

src/OpenIddict.Core/Caches/OpenIddictApplicationCache.cs

@@ -24,7 +24,7 @@ namespace OpenIddict.Core
     public class OpenIddictApplicationCache<TApplication> : IOpenIddictApplicationCache<TApplication>, IDisposable where TApplication : class
     {
         private readonly MemoryCache _cache;
-        private readonly ConcurrentDictionary<string, Lazy<CancellationTokenSource>> _signals;
+        private readonly ConcurrentDictionary<string, CancellationTokenSource> _signals;
         private readonly IOpenIddictApplicationStore<TApplication> _store;
 
         public OpenIddictApplicationCache(
@@ -36,7 +36,7 @@ namespace OpenIddict.Core
                 SizeLimit = options.CurrentValue.EntityCacheLimit
             });
 
-            _signals = new ConcurrentDictionary<string, Lazy<CancellationTokenSource>>(StringComparer.Ordinal);
+            _signals = new ConcurrentDictionary<string, CancellationTokenSource>(StringComparer.Ordinal);
             _store = resolver.Get<TApplication>();
         }
 
@@ -121,7 +121,7 @@ namespace OpenIddict.Core
         {
             foreach (var signal in _signals)
             {
-                signal.Value.Value.Dispose();
+                signal.Value.Dispose();
             }
 
             _cache.Dispose();
@@ -378,11 +378,9 @@ namespace OpenIddict.Core
                 throw new InvalidOperationException("The application identifier cannot be extracted.");
             }
 
-            if (_signals.TryGetValue(identifier, out Lazy<CancellationTokenSource> signal))
+            if (_signals.TryRemove(identifier, out CancellationTokenSource signal))
             {
-                signal.Value.Cancel();
-
-                _signals.TryRemove(identifier, out signal);
+                signal.Cancel();
             }
         }
 
@@ -410,15 +408,9 @@ namespace OpenIddict.Core
                 throw new InvalidOperationException("The application identifier cannot be extracted.");
             }
 
-            var signal = _signals.GetOrAdd(identifier, delegate
-            {
-                // Note: a Lazy<CancellationTokenSource> is used here to ensure only one CancellationTokenSource
-                // can be created. Not doing so would result in expiration signals being potentially linked to
-                // multiple sources, with a single one of them being eventually tracked and thus, cancelable.
-                return new Lazy<CancellationTokenSource>(() => new CancellationTokenSource());
-            });
+            var signal = _signals.GetOrAdd(identifier, _ => new CancellationTokenSource());
 
-            return new CancellationChangeToken(signal.Value.Token);
+            return new CancellationChangeToken(signal.Token);
         }
     }
 }

src/OpenIddict.Core/Caches/OpenIddictAuthorizationCache.cs

@@ -24,7 +24,7 @@ namespace OpenIddict.Core
     public class OpenIddictAuthorizationCache<TAuthorization> : IOpenIddictAuthorizationCache<TAuthorization>, IDisposable where TAuthorization : class
     {
         private readonly MemoryCache _cache;
-        private readonly ConcurrentDictionary<string, Lazy<CancellationTokenSource>> _signals;
+        private readonly ConcurrentDictionary<string, CancellationTokenSource> _signals;
         private readonly IOpenIddictAuthorizationStore<TAuthorization> _store;
 
         public OpenIddictAuthorizationCache(
@@ -36,7 +36,7 @@ namespace OpenIddict.Core
                 SizeLimit = options.CurrentValue.EntityCacheLimit
             });
 
-            _signals = new ConcurrentDictionary<string, Lazy<CancellationTokenSource>>(StringComparer.Ordinal);
+            _signals = new ConcurrentDictionary<string, CancellationTokenSource>(StringComparer.Ordinal);
             _store = resolver.Get<TAuthorization>();
         }
 
@@ -122,7 +122,7 @@ namespace OpenIddict.Core
         {
             foreach (var signal in _signals)
             {
-                signal.Value.Value.Dispose();
+                signal.Value.Dispose();
             }
 
             _cache.Dispose();
@@ -596,11 +596,9 @@ namespace OpenIddict.Core
                 throw new InvalidOperationException("The application identifier cannot be extracted.");
             }
 
-            if (_signals.TryGetValue(identifier, out Lazy<CancellationTokenSource> signal))
+            if (_signals.TryRemove(identifier, out CancellationTokenSource signal))
             {
-                signal.Value.Cancel();
-
-                _signals.TryRemove(identifier, out signal);
+                signal.Cancel();
             }
         }
 
@@ -628,15 +626,9 @@ namespace OpenIddict.Core
                 throw new InvalidOperationException("The authorization identifier cannot be extracted.");
             }
 
-            var signal = _signals.GetOrAdd(identifier, delegate
-            {
-                // Note: a Lazy<CancellationTokenSource> is used here to ensure only one CancellationTokenSource
-                // can be created. Not doing so would result in expiration signals being potentially linked to
-                // multiple sources, with a single one of them being eventually tracked and thus, cancelable.
-                return new Lazy<CancellationTokenSource>(() => new CancellationTokenSource());
-            });
+            var signal = _signals.GetOrAdd(identifier, _ => new CancellationTokenSource());
 
-            return new CancellationChangeToken(signal.Value.Token);
+            return new CancellationChangeToken(signal.Token);
         }
     }
 }

src/OpenIddict.Core/Caches/OpenIddictScopeCache.cs

@@ -25,7 +25,7 @@ namespace OpenIddict.Core
     public class OpenIddictScopeCache<TScope> : IOpenIddictScopeCache<TScope>, IDisposable where TScope : class
     {
         private readonly MemoryCache _cache;
-        private readonly ConcurrentDictionary<string, Lazy<CancellationTokenSource>> _signals;
+        private readonly ConcurrentDictionary<string, CancellationTokenSource> _signals;
         private readonly IOpenIddictScopeStore<TScope> _store;
 
         public OpenIddictScopeCache(
@@ -37,7 +37,7 @@ namespace OpenIddict.Core
                 SizeLimit = options.CurrentValue.EntityCacheLimit
             });
 
-            _signals = new ConcurrentDictionary<string, Lazy<CancellationTokenSource>>(StringComparer.Ordinal);
+            _signals = new ConcurrentDictionary<string, CancellationTokenSource>(StringComparer.Ordinal);
             _store = resolver.Get<TScope>();
         }
 
@@ -113,7 +113,7 @@ namespace OpenIddict.Core
         {
             foreach (var signal in _signals)
             {
-                signal.Value.Value.Dispose();
+                signal.Value.Dispose();
             }
 
             _cache.Dispose();
@@ -349,11 +349,9 @@ namespace OpenIddict.Core
                 throw new InvalidOperationException("The application identifier cannot be extracted.");
             }
 
-            if (_signals.TryGetValue(identifier, out Lazy<CancellationTokenSource> signal))
+            if (_signals.TryRemove(identifier, out CancellationTokenSource signal))
             {
-                signal.Value.Cancel();
-
-                _signals.TryRemove(identifier, out signal);
+                signal.Cancel();
             }
         }
 
@@ -380,15 +378,9 @@ namespace OpenIddict.Core
                 throw new InvalidOperationException("The scope identifier cannot be extracted.");
             }
 
-            var signal = _signals.GetOrAdd(identifier, delegate
-            {
-                // Note: a Lazy<CancellationTokenSource> is used here to ensure only one CancellationTokenSource
-                // can be created. Not doing so would result in expiration signals being potentially linked to
-                // multiple sources, with a single one of them being eventually tracked and thus, cancelable.
-                return new Lazy<CancellationTokenSource>(() => new CancellationTokenSource());
-            });
+            var signal = _signals.GetOrAdd(identifier, _ => new CancellationTokenSource());
 
-            return new CancellationChangeToken(signal.Value.Token);
+            return new CancellationChangeToken(signal.Token);
         }
     }
 }

src/OpenIddict.Core/Caches/OpenIddictTokenCache.cs

@@ -24,7 +24,7 @@ namespace OpenIddict.Core
     public class OpenIddictTokenCache<TToken> : IOpenIddictTokenCache<TToken>, IDisposable where TToken : class
     {
         private readonly MemoryCache _cache;
-        private readonly ConcurrentDictionary<string, Lazy<CancellationTokenSource>> _signals;
+        private readonly ConcurrentDictionary<string, CancellationTokenSource> _signals;
         private readonly IOpenIddictTokenStore<TToken> _store;
 
         public OpenIddictTokenCache(
@@ -36,7 +36,7 @@ namespace OpenIddict.Core
                 SizeLimit = options.CurrentValue.EntityCacheLimit
             });
 
-            _signals = new ConcurrentDictionary<string, Lazy<CancellationTokenSource>>(StringComparer.Ordinal);
+            _signals = new ConcurrentDictionary<string, CancellationTokenSource>(StringComparer.Ordinal);
             _store = resolver.Get<TToken>();
         }
 
@@ -145,7 +145,7 @@ namespace OpenIddict.Core
         {
             foreach (var signal in _signals)
             {
-                signal.Value.Value.Dispose();
+                signal.Value.Dispose();
             }
 
             _cache.Dispose();
@@ -679,11 +679,9 @@ namespace OpenIddict.Core
                 throw new InvalidOperationException("The application identifier cannot be extracted.");
             }
 
-            if (_signals.TryGetValue(identifier, out Lazy<CancellationTokenSource> signal))
+            if (_signals.TryRemove(identifier, out CancellationTokenSource signal))
             {
-                signal.Value.Cancel();
-
-                _signals.TryRemove(identifier, out signal);
+                signal.Cancel();
             }
         }
 
@@ -710,15 +708,9 @@ namespace OpenIddict.Core
                 throw new InvalidOperationException("The token identifier cannot be extracted.");
             }
 
-            var signal = _signals.GetOrAdd(identifier, delegate
-            {
-                // Note: a Lazy<CancellationTokenSource> is used here to ensure only one CancellationTokenSource
-                // can be created. Not doing so would result in expiration signals being potentially linked to
-                // multiple sources, with a single one of them being eventually tracked and thus, cancelable.
-                return new Lazy<CancellationTokenSource>(() => new CancellationTokenSource());
-            });
+            var signal = _signals.GetOrAdd(identifier, _ => new CancellationTokenSource());
 
-            return new CancellationChangeToken(signal.Value.Token);
+            return new CancellationChangeToken(signal.Token);
         }
     }
 }