Ensure Sync stream serialization is handling IAsyncEnumerable correctly (#67035)

eiriktsarpalis · web-flow · commit 2bf30a03b3f7 · 2022-03-24T13:26:46.000Z
* Fix #66687 * enable small buffer async tests for collections
diff --git a/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Converters/Collection/IAsyncEnumerableOfTConverter.cs b/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Converters/Collection/IAsyncEnumerableOfTConverter.cs
@@ -34,7 +34,7 @@ protected override void CreateCollection(ref Utf8JsonReader reader, ref ReadStac
 
         internal override bool OnTryWrite(Utf8JsonWriter writer, TAsyncEnumerable value, JsonSerializerOptions options, ref WriteStack state)
         {
-            if (!state.SupportContinuation)
+            if (!state.SupportAsync)
             {
                 ThrowHelper.ThrowNotSupportedException_TypeRequiresAsyncSerialization(TypeToConvert);
             }
diff --git a/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/JsonResumableConverterOfT.cs b/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/JsonResumableConverterOfT.cs
@@ -25,7 +25,7 @@ public sealed override void Write(Utf8JsonWriter writer, T value, JsonSerializer
             // Bridge from resumable to value converters.
 
             WriteStack state = default;
-            state.Initialize(typeof(T), options, supportContinuation: false);
+            state.Initialize(typeof(T), options, supportContinuation: false, supportAsync: false);
             try
             {
                 TryWrite(writer, value, options, ref state);
diff --git a/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/JsonSerializer.Write.Helpers.cs b/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/JsonSerializer.Write.Helpers.cs
@@ -64,7 +64,7 @@ jsonTypeInfo is not JsonTypeInfo<TValue> ||
                 "Incorrect method called. WriteUsingGeneratedSerializer() should have been called instead.");
 
             WriteStack state = default;
-            state.Initialize(jsonTypeInfo, supportContinuation: false);
+            state.Initialize(jsonTypeInfo, supportContinuation: false, supportAsync: false);
 
             JsonConverter converter = jsonTypeInfo.PropertyInfoForTypeInfo.ConverterBase;
             Debug.Assert(converter != null);
diff --git a/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/JsonSerializer.Write.Stream.cs b/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/JsonSerializer.Write.Stream.cs
@@ -256,7 +256,7 @@ private static async Task WriteStreamAsync<TValue>(
             using (var writer = new Utf8JsonWriter(bufferWriter, writerOptions))
             {
                 WriteStack state = new WriteStack { CancellationToken = cancellationToken };
-                JsonConverter converter = state.Initialize(jsonTypeInfo, supportContinuation: true);
+                JsonConverter converter = state.Initialize(jsonTypeInfo, supportContinuation: true, supportAsync: true);
 
                 bool isFinalBlock;
 
@@ -329,7 +329,7 @@ private static void WriteStream<TValue>(
             using (var writer = new Utf8JsonWriter(bufferWriter, writerOptions))
             {
                 WriteStack state = default;
-                JsonConverter converter = state.Initialize(jsonTypeInfo, supportContinuation: true);
+                JsonConverter converter = state.Initialize(jsonTypeInfo, supportContinuation: true, supportAsync: false);
 
                 bool isFinalBlock;
 
diff --git a/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/WriteStack.cs b/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/WriteStack.cs
@@ -78,6 +78,11 @@ internal struct WriteStack
         /// </summary>
         public bool SupportContinuation;
 
+        /// <summary>
+        /// Internal flag indicating that async serialization is supported. Implies `SupportContinuation`.
+        /// </summary>
+        public bool SupportAsync;
+
         /// <summary>
         /// Stores a reference id that has been calculated for a newly serialized object.
         /// </summary>
@@ -98,14 +103,16 @@ private void EnsurePushCapacity()
         /// <summary>
         /// Initialize the state without delayed initialization of the JsonTypeInfo.
         /// </summary>
-        public JsonConverter Initialize(Type type, JsonSerializerOptions options, bool supportContinuation)
+        public JsonConverter Initialize(Type type, JsonSerializerOptions options, bool supportContinuation, bool supportAsync)
         {
             JsonTypeInfo jsonTypeInfo = options.GetOrAddJsonTypeInfoForRootType(type);
-            return Initialize(jsonTypeInfo, supportContinuation);
+            return Initialize(jsonTypeInfo, supportContinuation, supportAsync);
         }
 
-        internal JsonConverter Initialize(JsonTypeInfo jsonTypeInfo, bool supportContinuation)
+        internal JsonConverter Initialize(JsonTypeInfo jsonTypeInfo, bool supportContinuation, bool supportAsync)
         {
+            Debug.Assert(!supportAsync || supportContinuation, "supportAsync implies supportContinuation.");
+
             Current.JsonTypeInfo = jsonTypeInfo;
             Current.JsonPropertyInfo = jsonTypeInfo.PropertyInfoForTypeInfo;
             Current.NumberHandling = Current.JsonPropertyInfo.NumberHandling;
@@ -118,6 +125,7 @@ internal JsonConverter Initialize(JsonTypeInfo jsonTypeInfo, bool supportContinu
             }
 
             SupportContinuation = supportContinuation;
+            SupportAsync = supportAsync;
 
             return jsonTypeInfo.PropertyInfoForTypeInfo.ConverterBase;
         }
diff --git a/src/libraries/System.Text.Json/tests/Common/CollectionTests/CollectionTests.AsyncEnumerable.cs b/src/libraries/System.Text.Json/tests/Common/CollectionTests/CollectionTests.AsyncEnumerable.cs
@@ -18,7 +18,7 @@ public abstract partial class CollectionTests
         [MemberData(nameof(GetAsyncEnumerableSources))]
         public async Task WriteRootLevelAsyncEnumerable<TElement>(IEnumerable<TElement> source, int delayInterval, int bufferSize)
         {
-            if (StreamingSerializer is null)
+            if (StreamingSerializer?.IsAsyncSerializer != true)
             {
                 return;
             }
@@ -43,7 +43,7 @@ public async Task WriteRootLevelAsyncEnumerable<TElement>(IEnumerable<TElement>
         [MemberData(nameof(GetAsyncEnumerableSources))]
         public async Task WriteNestedAsyncEnumerable<TElement>(IEnumerable<TElement> source, int delayInterval, int bufferSize)
         {
-            if (StreamingSerializer is null)
+            if (StreamingSerializer?.IsAsyncSerializer != true)
             {
                 return;
             }
@@ -68,7 +68,7 @@ public async Task WriteNestedAsyncEnumerable<TElement>(IEnumerable<TElement> sou
         [MemberData(nameof(GetAsyncEnumerableSources))]
         public async Task WriteNestedAsyncEnumerable_DTO<TElement>(IEnumerable<TElement> source, int delayInterval, int bufferSize)
         {
-            if (StreamingSerializer is null)
+            if (StreamingSerializer?.IsAsyncSerializer != true)
             {
                 return;
             }
@@ -93,7 +93,7 @@ public async Task WriteNestedAsyncEnumerable_DTO<TElement>(IEnumerable<TElement>
         [MemberData(nameof(GetAsyncEnumerableSources))]
         public async Task WriteNestedAsyncEnumerable_Nullable<TElement>(IEnumerable<TElement> source, int delayInterval, int bufferSize)
         {
-            if (StreamingSerializer is null)
+            if (StreamingSerializer?.IsAsyncSerializer != true)
             {
                 return;
             }
@@ -151,7 +151,7 @@ public class AsyncEnumerableDto<TElement>
         [MemberData(nameof(GetAsyncEnumerableSources))]
         public async Task WriteSequentialNestedAsyncEnumerables<TElement>(IEnumerable<TElement> source, int delayInterval, int bufferSize)
         {
-            if (StreamingSerializer is null)
+            if (StreamingSerializer?.IsAsyncSerializer != true)
             {
                 return;
             }
@@ -176,7 +176,7 @@ public async Task WriteSequentialNestedAsyncEnumerables<TElement>(IEnumerable<TE
         [MemberData(nameof(GetAsyncEnumerableSources))]
         public async Task WriteAsyncEnumerableOfAsyncEnumerables<TElement>(IEnumerable<TElement> source, int delayInterval, int bufferSize)
         {
-            if (StreamingSerializer is null)
+            if (StreamingSerializer?.IsAsyncSerializer != true)
             {
                 return;
             }
@@ -209,19 +209,21 @@ public void WriteRootLevelAsyncEnumerableSync_ThrowsNotSupportedException()
         {
             IAsyncEnumerable<int> asyncEnumerable = new MockedAsyncEnumerable<int>(Enumerable.Range(1, 10));
             Assert.Throws<NotSupportedException>(() => JsonSerializer.Serialize(asyncEnumerable));
+            Assert.Throws<NotSupportedException>(() => JsonSerializer.Serialize(new MemoryStream(), asyncEnumerable));
         }
 
         [Fact]
         public void WriteNestedAsyncEnumerableSync_ThrowsNotSupportedException()
         {
             IAsyncEnumerable<int> asyncEnumerable = new MockedAsyncEnumerable<int>(Enumerable.Range(1, 10));
             Assert.Throws<NotSupportedException>(() => JsonSerializer.Serialize(new { Data = asyncEnumerable }));
+            Assert.Throws<NotSupportedException>(() => JsonSerializer.Serialize(new MemoryStream(), new { Data = asyncEnumerable }));
         }
 
         [Fact]
         public async Task WriteAsyncEnumerable_ElementSerializationThrows_ShouldDisposeEnumerator()
         {
-            if (StreamingSerializer is null)
+            if (StreamingSerializer?.IsAsyncSerializer != true)
             {
                 return;
             }
@@ -243,7 +245,7 @@ static IEnumerable<int> ThrowingEnumerable()
         [Fact]
         public async Task ReadRootLevelAsyncEnumerable()
         {
-            if (StreamingSerializer is null)
+            if (StreamingSerializer?.IsAsyncSerializer != true)
             {
                 return;
             }
@@ -257,7 +259,7 @@ public async Task ReadRootLevelAsyncEnumerable()
         [Fact]
         public async Task ReadNestedAsyncEnumerable()
         {
-            if (StreamingSerializer is null)
+            if (StreamingSerializer?.IsAsyncSerializer != true)
             {
                 return;
             }
@@ -271,7 +273,7 @@ public async Task ReadNestedAsyncEnumerable()
         [Fact]
         public async Task ReadAsyncEnumerableOfAsyncEnumerables()
         {
-            if (StreamingSerializer is null)
+            if (StreamingSerializer?.IsAsyncSerializer != true)
             {
                 return;
             }
@@ -289,7 +291,7 @@ public async Task ReadAsyncEnumerableOfAsyncEnumerables()
         [Fact]
         public async Task ReadRootLevelAsyncEnumerableDerivative_ThrowsNotSupportedException()
         {
-            if (StreamingSerializer is null)
+            if (StreamingSerializer?.IsAsyncSerializer != true)
             {
                 return;
             }
@@ -314,7 +316,7 @@ public static IEnumerable<object[]> GetAsyncEnumerableSources()
         [Fact]
         public async Task RegressionTest_DisposingEnumeratorOnPendingMoveNextAsyncOperation()
         {
-            if (StreamingSerializer is null)
+            if (StreamingSerializer?.IsAsyncSerializer != true)
             {
                 return;
             }
@@ -338,7 +340,7 @@ static async IAsyncEnumerable<int> GetNumbersAsync()
         [Fact]
         public async Task RegressionTest_ExceptionOnFirstMoveNextShouldNotFlushBuffer()
         {
-            if (StreamingSerializer is null)
+            if (StreamingSerializer?.IsAsyncSerializer != true)
             {
                 return;
             }
diff --git a/src/libraries/System.Text.Json/tests/Common/StreamingJsonSerializerWrapper.cs b/src/libraries/System.Text.Json/tests/Common/StreamingJsonSerializerWrapper.cs
@@ -15,7 +15,7 @@ public abstract partial class StreamingJsonSerializerWrapper : JsonSerializerWra
         /// <summary>
         /// True if the serializer is streaming data synchronously.
         /// </summary>
-        public virtual bool IsBlockingSerializer => false;
+        public abstract bool IsAsyncSerializer { get; }
 
         public abstract Task SerializeWrapper(Stream stream, object value, Type inputType, JsonSerializerOptions? options = null);
         public abstract Task SerializeWrapper<T>(Stream stream, T value, JsonSerializerOptions? options = null);
diff --git a/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/Serialization/JsonSerializerWrapper.SourceGen.cs b/src/libraries/System.Text.Json/tests/System.Text.Json.SourceGeneration.Tests/Serialization/JsonSerializerWrapper.SourceGen.cs
@@ -84,6 +84,8 @@ internal sealed class AsyncStreamSerializerWrapper : StreamingJsonSerializerWrap
         private readonly JsonSerializerContext _defaultContext;
         private readonly Func<JsonSerializerOptions, JsonSerializerContext> _customContextCreator;
 
+        public override bool IsAsyncSerializer => true;
+
         public AsyncStreamSerializerWrapper(JsonSerializerContext defaultContext!!, Func<JsonSerializerOptions, JsonSerializerContext> customContextCreator!!)
         {
             _defaultContext = defaultContext;
diff --git a/src/libraries/System.Text.Json/tests/System.Text.Json.Tests/Serialization/CollectionTests.cs b/src/libraries/System.Text.Json/tests/System.Text.Json.Tests/Serialization/CollectionTests.cs
@@ -15,7 +15,11 @@ public sealed partial class CollectionTestsDynamic_AsyncStream : CollectionTests
         public CollectionTestsDynamic_AsyncStream() : base(JsonSerializerWrapper.AsyncStreamSerializer) { }
     }
 
-    [ActiveIssue("https://github.com/dotnet/runtime/issues/66687")]
+    public sealed partial class CollectionTestsDynamic_AsyncStreamWithSmallBuffer : CollectionTests
+    {
+        public CollectionTestsDynamic_AsyncStreamWithSmallBuffer() : base(JsonSerializerWrapper.AsyncStreamSerializerWithSmallBuffer) { }
+    }
+
     public sealed partial class CollectionTestsDynamic_SyncStream : CollectionTests
     {
         public CollectionTestsDynamic_SyncStream() : base(JsonSerializerWrapper.SyncStreamSerializer) { }
diff --git a/src/libraries/System.Text.Json/tests/System.Text.Json.Tests/Serialization/JsonSerializerWrapper.Reflection.cs b/src/libraries/System.Text.Json/tests/System.Text.Json.Tests/Serialization/JsonSerializerWrapper.Reflection.cs
@@ -122,6 +122,8 @@ private class AsyncStreamSerializerWrapper : StreamingJsonSerializerWrapper
         {
             private readonly bool _forceSmallBufferInOptions;
 
+            public override bool IsAsyncSerializer => true;
+
             public AsyncStreamSerializerWrapper(bool forceSmallBufferInOptions = false)
             {
                 _forceSmallBufferInOptions = forceSmallBufferInOptions;
@@ -183,7 +185,7 @@ public SyncStreamSerializerWrapper(bool forceSmallBufferInOptions = false)
             private JsonSerializerOptions? ResolveOptionsInstance(JsonSerializerOptions? options)
                 => _forceSmallBufferInOptions ? JsonSerializerOptionsSmallBufferMapper.ResolveOptionsInstanceWithSmallBuffer(options) : options;
 
-            public override bool IsBlockingSerializer => true;
+            public override bool IsAsyncSerializer => false;
 
             public override Task SerializeWrapper<T>(Stream utf8Json, T value, JsonSerializerOptions options = null)
             {

Original file line number	Diff line number	Diff line change
`@@ -34,7 +34,7 @@ protected override void CreateCollection(ref Utf8JsonReader reader, ref ReadStac`
`34`	`34`
`35`	`35`	`internal override bool OnTryWrite(Utf8JsonWriter writer, TAsyncEnumerable value, JsonSerializerOptions options, ref WriteStack state)`
`36`	`36`	`{`
`37`		`- if (!state.SupportContinuation)`
	`37`	`+ if (!state.SupportAsync)`
`38`	`38`	`{`
`39`	`39`	`ThrowHelper.ThrowNotSupportedException_TypeRequiresAsyncSerialization(TypeToConvert);`
`40`	`40`	`}`
Original file line number	Diff line number	Diff line change
`@@ -25,7 +25,7 @@ public sealed override void Write(Utf8JsonWriter writer, T value, JsonSerializer`
`25`	`25`	`// Bridge from resumable to value converters.`
`26`	`26`
`27`	`27`	`WriteStack state = default;`
`28`		`- state.Initialize(typeof(T), options, supportContinuation: false);`
	`28`	`+ state.Initialize(typeof(T), options, supportContinuation: false, supportAsync: false);`
`29`	`29`	`try`
`30`	`30`	`{`
`31`	`31`	`TryWrite(writer, value, options, ref state);`
Original file line number	Diff line number	Diff line change
`@@ -256,7 +256,7 @@ private static async Task WriteStreamAsync<TValue>(`
`256`	`256`	`using (var writer = new Utf8JsonWriter(bufferWriter, writerOptions))`
`257`	`257`	`{`
`258`	`258`	`WriteStack state = new WriteStack { CancellationToken = cancellationToken };`
`259`		`- JsonConverter converter = state.Initialize(jsonTypeInfo, supportContinuation: true);`
	`259`	`+ JsonConverter converter = state.Initialize(jsonTypeInfo, supportContinuation: true, supportAsync: true);`
`260`	`260`
`261`	`261`	`bool isFinalBlock;`
`262`	`262`
`@@ -329,7 +329,7 @@ private static void WriteStream<TValue>(`
`329`	`329`	`using (var writer = new Utf8JsonWriter(bufferWriter, writerOptions))`
`330`	`330`	`{`
`331`	`331`	`WriteStack state = default;`
`332`		`- JsonConverter converter = state.Initialize(jsonTypeInfo, supportContinuation: true);`
	`332`	`+ JsonConverter converter = state.Initialize(jsonTypeInfo, supportContinuation: true, supportAsync: false);`
`333`	`333`
`334`	`334`	`bool isFinalBlock;`
`335`	`335`
Original file line number	Diff line number	Diff line change
`@@ -18,7 +18,7 @@ public abstract partial class CollectionTests`
`18`	`18`	`[MemberData(nameof(GetAsyncEnumerableSources))]`
`19`	`19`	`public async Task WriteRootLevelAsyncEnumerable<TElement>(IEnumerable<TElement> source, int delayInterval, int bufferSize)`
`20`	`20`	`{`
`21`		`- if (StreamingSerializer is null)`
	`21`	`+ if (StreamingSerializer?.IsAsyncSerializer != true)`
`22`	`22`	`{`
`23`	`23`	`return;`
`24`	`24`	`}`
`@@ -43,7 +43,7 @@ public async Task WriteRootLevelAsyncEnumerable<TElement>(IEnumerable<TElement>`
`43`	`43`	`[MemberData(nameof(GetAsyncEnumerableSources))]`
`44`	`44`	`public async Task WriteNestedAsyncEnumerable<TElement>(IEnumerable<TElement> source, int delayInterval, int bufferSize)`
`45`	`45`	`{`
`46`		`- if (StreamingSerializer is null)`
	`46`	`+ if (StreamingSerializer?.IsAsyncSerializer != true)`
`47`	`47`	`{`
`48`	`48`	`return;`
`49`	`49`	`}`
`@@ -68,7 +68,7 @@ public async Task WriteNestedAsyncEnumerable<TElement>(IEnumerable<TElement> sou`
`68`	`68`	`[MemberData(nameof(GetAsyncEnumerableSources))]`
`69`	`69`	`public async Task WriteNestedAsyncEnumerable_DTO<TElement>(IEnumerable<TElement> source, int delayInterval, int bufferSize)`
`70`	`70`	`{`
`71`		`- if (StreamingSerializer is null)`
	`71`	`+ if (StreamingSerializer?.IsAsyncSerializer != true)`
`72`	`72`	`{`
`73`	`73`	`return;`
`74`	`74`	`}`
`@@ -93,7 +93,7 @@ public async Task WriteNestedAsyncEnumerable_DTO<TElement>(IEnumerable<TElement>`
`93`	`93`	`[MemberData(nameof(GetAsyncEnumerableSources))]`
`94`	`94`	`public async Task WriteNestedAsyncEnumerable_Nullable<TElement>(IEnumerable<TElement> source, int delayInterval, int bufferSize)`
`95`	`95`	`{`
`96`		`- if (StreamingSerializer is null)`
	`96`	`+ if (StreamingSerializer?.IsAsyncSerializer != true)`
`97`	`97`	`{`
`98`	`98`	`return;`
`99`	`99`	`}`
`@@ -151,7 +151,7 @@ public class AsyncEnumerableDto<TElement>`
`151`	`151`	`[MemberData(nameof(GetAsyncEnumerableSources))]`
`152`	`152`	`public async Task WriteSequentialNestedAsyncEnumerables<TElement>(IEnumerable<TElement> source, int delayInterval, int bufferSize)`
`153`	`153`	`{`
`154`		`- if (StreamingSerializer is null)`
	`154`	`+ if (StreamingSerializer?.IsAsyncSerializer != true)`
`155`	`155`	`{`
`156`	`156`	`return;`
`157`	`157`	`}`
`@@ -176,7 +176,7 @@ public async Task WriteSequentialNestedAsyncEnumerables<TElement>(IEnumerable<TE`
`176`	`176`	`[MemberData(nameof(GetAsyncEnumerableSources))]`
`177`	`177`	`public async Task WriteAsyncEnumerableOfAsyncEnumerables<TElement>(IEnumerable<TElement> source, int delayInterval, int bufferSize)`
`178`	`178`	`{`
`179`		`- if (StreamingSerializer is null)`
	`179`	`+ if (StreamingSerializer?.IsAsyncSerializer != true)`
`180`	`180`	`{`
`181`	`181`	`return;`
`182`	`182`	`}`
`@@ -209,19 +209,21 @@ public void WriteRootLevelAsyncEnumerableSync_ThrowsNotSupportedException()`
`209`	`209`	`{`
`210`	`210`	`IAsyncEnumerable<int> asyncEnumerable = new MockedAsyncEnumerable<int>(Enumerable.Range(1, 10));`
`211`	`211`	`Assert.Throws<NotSupportedException>(() => JsonSerializer.Serialize(asyncEnumerable));`
	`212`	`+ Assert.Throws<NotSupportedException>(() => JsonSerializer.Serialize(new MemoryStream(), asyncEnumerable));`
`212`	`213`	`}`
`213`	`214`
`214`	`215`	`[Fact]`
`215`	`216`	`public void WriteNestedAsyncEnumerableSync_ThrowsNotSupportedException()`
`216`	`217`	`{`
`217`	`218`	`IAsyncEnumerable<int> asyncEnumerable = new MockedAsyncEnumerable<int>(Enumerable.Range(1, 10));`
`218`	`219`	`Assert.Throws<NotSupportedException>(() => JsonSerializer.Serialize(new { Data = asyncEnumerable }));`
	`220`	`+ Assert.Throws<NotSupportedException>(() => JsonSerializer.Serialize(new MemoryStream(), new { Data = asyncEnumerable }));`
`219`	`221`	`}`
`220`	`222`
`221`	`223`	`[Fact]`
`222`	`224`	`public async Task WriteAsyncEnumerable_ElementSerializationThrows_ShouldDisposeEnumerator()`
`223`	`225`	`{`
`224`		`- if (StreamingSerializer is null)`
	`226`	`+ if (StreamingSerializer?.IsAsyncSerializer != true)`
`225`	`227`	`{`
`226`	`228`	`return;`
`227`	`229`	`}`
`@@ -243,7 +245,7 @@ static IEnumerable<int> ThrowingEnumerable()`
`243`	`245`	`[Fact]`
`244`	`246`	`public async Task ReadRootLevelAsyncEnumerable()`
`245`	`247`	`{`
`246`		`- if (StreamingSerializer is null)`
	`248`	`+ if (StreamingSerializer?.IsAsyncSerializer != true)`
`247`	`249`	`{`
`248`	`250`	`return;`
`249`	`251`	`}`
`@@ -257,7 +259,7 @@ public async Task ReadRootLevelAsyncEnumerable()`
`257`	`259`	`[Fact]`
`258`	`260`	`public async Task ReadNestedAsyncEnumerable()`
`259`	`261`	`{`
`260`		`- if (StreamingSerializer is null)`
	`262`	`+ if (StreamingSerializer?.IsAsyncSerializer != true)`
`261`	`263`	`{`
`262`	`264`	`return;`
`263`	`265`	`}`
`@@ -271,7 +273,7 @@ public async Task ReadNestedAsyncEnumerable()`
`271`	`273`	`[Fact]`
`272`	`274`	`public async Task ReadAsyncEnumerableOfAsyncEnumerables()`
`273`	`275`	`{`
`274`		`- if (StreamingSerializer is null)`
	`276`	`+ if (StreamingSerializer?.IsAsyncSerializer != true)`
`275`	`277`	`{`
`276`	`278`	`return;`
`277`	`279`	`}`
`@@ -289,7 +291,7 @@ public async Task ReadAsyncEnumerableOfAsyncEnumerables()`
`289`	`291`	`[Fact]`
`290`	`292`	`public async Task ReadRootLevelAsyncEnumerableDerivative_ThrowsNotSupportedException()`
`291`	`293`	`{`
`292`		`- if (StreamingSerializer is null)`
	`294`	`+ if (StreamingSerializer?.IsAsyncSerializer != true)`
`293`	`295`	`{`
`294`	`296`	`return;`
`295`	`297`	`}`
`@@ -314,7 +316,7 @@ public static IEnumerable<object[]> GetAsyncEnumerableSources()`
`314`	`316`	`[Fact]`
`315`	`317`	`public async Task RegressionTest_DisposingEnumeratorOnPendingMoveNextAsyncOperation()`
`316`	`318`	`{`
`317`		`- if (StreamingSerializer is null)`
	`319`	`+ if (StreamingSerializer?.IsAsyncSerializer != true)`
`318`	`320`	`{`
`319`	`321`	`return;`
`320`	`322`	`}`
`@@ -338,7 +340,7 @@ static async IAsyncEnumerable<int> GetNumbersAsync()`
`338`	`340`	`[Fact]`
`339`	`341`	`public async Task RegressionTest_ExceptionOnFirstMoveNextShouldNotFlushBuffer()`
`340`	`342`	`{`
`341`		`- if (StreamingSerializer is null)`
	`343`	`+ if (StreamingSerializer?.IsAsyncSerializer != true)`
`342`	`344`	`{`
`343`	`345`	`return;`
`344`	`346`	`}`
Original file line number	Diff line number	Diff line change
`@@ -84,6 +84,8 @@ internal sealed class AsyncStreamSerializerWrapper : StreamingJsonSerializerWrap`
`84`	`84`	`private readonly JsonSerializerContext _defaultContext;`
`85`	`85`	`private readonly Func<JsonSerializerOptions, JsonSerializerContext> _customContextCreator;`
`86`	`86`
	`87`	`+ public override bool IsAsyncSerializer => true;`
	`88`	`+`
`87`	`89`	`public AsyncStreamSerializerWrapper(JsonSerializerContext defaultContext!!, Func<JsonSerializerOptions, JsonSerializerContext> customContextCreator!!)`
`88`	`90`	`{`
`89`	`91`	`_defaultContext = defaultContext;`
Original file line number	Diff line number	Diff line change
`@@ -15,7 +15,11 @@ public sealed partial class CollectionTestsDynamic_AsyncStream : CollectionTests`
`15`	`15`	`public CollectionTestsDynamic_AsyncStream() : base(JsonSerializerWrapper.AsyncStreamSerializer) { }`
`16`	`16`	`}`
`17`	`17`
`18`		`- [ActiveIssue("https://github.com/dotnet/runtime/issues/66687")]`
	`18`	`+ public sealed partial class CollectionTestsDynamic_AsyncStreamWithSmallBuffer : CollectionTests`
	`19`	`+ {`
	`20`	`+ public CollectionTestsDynamic_AsyncStreamWithSmallBuffer() : base(JsonSerializerWrapper.AsyncStreamSerializerWithSmallBuffer) { }`
	`21`	`+ }`
	`22`	`+`
`19`	`23`	`public sealed partial class CollectionTestsDynamic_SyncStream : CollectionTests`
`20`	`24`	`{`
`21`	`25`	`public CollectionTestsDynamic_SyncStream() : base(JsonSerializerWrapper.SyncStreamSerializer) { }`
Original file line number	Diff line number	Diff line change
`@@ -122,6 +122,8 @@ private class AsyncStreamSerializerWrapper : StreamingJsonSerializerWrapper`
`122`	`122`	`{`
`123`	`123`	`private readonly bool _forceSmallBufferInOptions;`
`124`	`124`
	`125`	`+ public override bool IsAsyncSerializer => true;`
	`126`	`+`
`125`	`127`	`public AsyncStreamSerializerWrapper(bool forceSmallBufferInOptions = false)`
`126`	`128`	`{`
`127`	`129`	`_forceSmallBufferInOptions = forceSmallBufferInOptions;`
`@@ -183,7 +185,7 @@ public SyncStreamSerializerWrapper(bool forceSmallBufferInOptions = false)`
`183`	`185`	`private JsonSerializerOptions? ResolveOptionsInstance(JsonSerializerOptions? options)`
`184`	`186`	`=> _forceSmallBufferInOptions ? JsonSerializerOptionsSmallBufferMapper.ResolveOptionsInstanceWithSmallBuffer(options) : options;`
`185`	`187`
`186`		`- public override bool IsBlockingSerializer => true;`
	`188`	`+ public override bool IsAsyncSerializer => false;`
`187`	`189`
`188`	`190`	`public override Task SerializeWrapper<T>(Stream utf8Json, T value, JsonSerializerOptions options = null)`
`189`	`191`	`{`