fix ByteArrayConverter null handling inconsistencies. (#56390)

Fixes #49728.
dotnet · Jul 27, 2021 · 59e7258 · 59e7258
1 parent eeb4f36
commit 59e7258
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Showing 3 changed files with 49 additions and 9 deletions.
diff --git a/...ystem.Text.Json/src/System/Text/Json/Serialization/Converters/Value/ByteArrayConverter.cs b/...ystem.Text.Json/src/System/Text/Json/Serialization/Converters/Value/ByteArrayConverter.cs
@@ -5,14 +5,26 @@ namespace System.Text.Json.Serialization.Converters
 {
     internal sealed class ByteArrayConverter : JsonConverter<byte[]>
     {
-        public override byte[] Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+        public override byte[]? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
+            if (reader.TokenType == JsonTokenType.Null)
+            {
+                return null;
+            }
+
             return reader.GetBytesFromBase64();
         }
 
-        public override void Write(Utf8JsonWriter writer, byte[] value, JsonSerializerOptions options)
+        public override void Write(Utf8JsonWriter writer, byte[]? value, JsonSerializerOptions options)
         {
-            writer.WriteBase64StringValue(value);
+            if (value == null)
+            {
+                writer.WriteNullValue();
+            }
+            else
+            {
+                writer.WriteBase64StringValue(value);
+            }
         }
     }
 }
diff --git a/src/libraries/System.Text.Json/tests/System.Text.Json.Tests/Serialization/Array.ReadTests.cs b/src/libraries/System.Text.Json/tests/System.Text.Json.Tests/Serialization/Array.ReadTests.cs
@@ -29,9 +29,22 @@ public static void ReadObjectArray()
         [Fact]
         public static void ReadNullByteArray()
         {
-            string json = @"null";
-            byte[] arr = JsonSerializer.Deserialize<byte[]>(json);
+            byte[] arr = JsonSerializer.Deserialize<byte[]>("null");
             Assert.Null(arr);
+
+            PocoWithByteArrayProperty poco = JsonSerializer.Deserialize<PocoWithByteArrayProperty>(@"{""Value"":null}");
+            Assert.Null(poco.Value);
+
+            byte[][] jaggedArr = JsonSerializer.Deserialize<byte[][]>(@"[null]");
+            Assert.Null(jaggedArr[0]);
+
+            Dictionary<string, byte[]> dict = JsonSerializer.Deserialize<Dictionary<string, byte[]>>(@"{""key"":null}");
+            Assert.Null(dict["key"]);
+        }
+
+        public class PocoWithByteArrayProperty
+        {
+            public byte[] Value { get; set; }
         }
 
         [Fact]

diff --git a/...libraries/System.Text.Json/tests/System.Text.Json.Tests/Serialization/Array.WriteTests.cs b/...libraries/System.Text.Json/tests/System.Text.Json.Tests/Serialization/Array.WriteTests.cs
@@ -40,12 +40,27 @@ public static void WriteEmptyByteArray()
             Assert.Equal(@"""""", json);
         }
 
-        [Fact]
-        public static void WriteByteArray()
+        [Theory]
+        [InlineData(null, "null")]
+        [InlineData(new byte[] { }, "\"\"")]
+        [InlineData(new byte[] { 1, 2 }, "\"AQI=\"")]
+        public static void WriteByteArray(byte[]? input, string expectedEncoding)
         {
-            var input = new byte[] { 1, 2 };
+            // root-level serialization
             string json = JsonSerializer.Serialize(input);
-            Assert.Equal($"\"{Convert.ToBase64String(input)}\"", json);
+            Assert.Equal(expectedEncoding, json);
+
+            // object property
+            json = JsonSerializer.Serialize(new { Property = input });
+            Assert.Equal(@$"{{""Property"":{expectedEncoding}}}", json);
+
+            // array element
+            json = JsonSerializer.Serialize(new[] { input });
+            Assert.Equal($"[{expectedEncoding}]", json);
+
+            // dictionary entry
+            json = JsonSerializer.Serialize(new Dictionary<string, byte[]> { ["key"] = input });
+            Assert.Equal(@$"{{""key"":{expectedEncoding}}}", json);
         }
 
         [Fact]