gRPC JSON transcoding — Fixed parsing string values into enum when provided string is not valid enum value (#52402)

Author: zorix

src/Grpc/JsonTranscoding/src/Microsoft.AspNetCore.Grpc.JsonTranscoding/Internal/Json/EnumConverter.cs

@@ -26,7 +26,13 @@ public EnumConverter(JsonContext context) : base(context)
                 {
                     throw new InvalidOperationException($"Unable to resolve descriptor for {typeToConvert}.");
                 }
-                var valueDescriptor = enumDescriptor.FindValueByName(reader.GetString()!);
+
+                var value = reader.GetString()!;
+                var valueDescriptor = enumDescriptor.FindValueByName(value);
+                if (valueDescriptor == null)
+                {
+                    throw new InvalidOperationException(@$"Error converting value ""{value}"" to enum type {typeToConvert}.");
+                }
 
                 return ConvertFromInteger(valueDescriptor.Number);
             case JsonTokenType.Number:

src/Grpc/JsonTranscoding/test/Microsoft.AspNetCore.Grpc.JsonTranscoding.Tests/ConverterTests/JsonConverterReadTests.cs

@@ -187,6 +187,31 @@ public void Enum_ReadNumber(int value)
         AssertReadJson<HelloRequest.Types.DataTypes>(json);
     }
 
+    [Theory]
+    [InlineData("FOO")]
+    [InlineData("BAR")]
+    [InlineData("NEG")]
+    public void Enum_ReadString(string value)
+    {
+        var serviceDescriptorRegistry = new DescriptorRegistry();
+        serviceDescriptorRegistry.RegisterFileDescriptor(JsonTranscodingGreeter.Descriptor.File);
+
+        var json = @$"{{ ""singleEnum"": ""{value}"" }}";
+
+        AssertReadJson<HelloRequest.Types.DataTypes>(json, descriptorRegistry: serviceDescriptorRegistry);
+    }
+
+    [Fact]
+    public void Enum_ReadString_NotAllowedValue()
+    {
+        var serviceDescriptorRegistry = new DescriptorRegistry();
+        serviceDescriptorRegistry.RegisterFileDescriptor(JsonTranscodingGreeter.Descriptor.File);
+
+        var json = @"{ ""singleEnum"": ""INVALID"" }";
+
+        AssertReadJsonError<HelloRequest.Types.DataTypes>(json, ex => Assert.Equal(@"Error converting value ""INVALID"" to enum type Transcoding.HelloRequest+Types+DataTypes+Types+NestedEnum.", ex.Message), descriptorRegistry: serviceDescriptorRegistry, deserializeOld: false);
+    }
+
     [Fact]
     public void Timestamp_Nested()
     {
@@ -603,7 +628,7 @@ public void JsonNamePriority_FieldNameFallback()
         return objectNew;
     }
 
-    private void AssertReadJsonError<TValue>(string value, Action<Exception> assertException, GrpcJsonSettings? settings = null, DescriptorRegistry? descriptorRegistry = null) where TValue : IMessage, new()
+    private void AssertReadJsonError<TValue>(string value, Action<Exception> assertException, GrpcJsonSettings? settings = null, DescriptorRegistry? descriptorRegistry = null, bool deserializeOld = true) where TValue : IMessage, new()
     {
         var typeRegistery = TypeRegistry.FromFiles(
             HelloRequest.Descriptor.File,
@@ -616,12 +641,15 @@ public void JsonNamePriority_FieldNameFallback()
         var ex = Assert.ThrowsAny<Exception>(() => JsonSerializer.Deserialize<TValue>(value, jsonSerializerOptions));
         assertException(ex);
 
-        var formatter = new JsonParser(new JsonParser.Settings(
-            recursionLimit: int.MaxValue,
-            typeRegistery));
+        if (deserializeOld)
+        {
+            var formatter = new JsonParser(new JsonParser.Settings(
+                recursionLimit: int.MaxValue,
+                typeRegistery));
 
-        ex = Assert.ThrowsAny<Exception>(() => formatter.Parse<TValue>(value));
-        assertException(ex);
+            ex = Assert.ThrowsAny<Exception>(() => formatter.Parse<TValue>(value));
+            assertException(ex);
+        }
     }
 
     internal static JsonSerializerOptions CreateSerializerOptions(GrpcJsonSettings? settings, TypeRegistry? typeRegistery, DescriptorRegistry descriptorRegistry)