Add property ordering feature (#55586)

steveharter · web-flow · commit 97202193214e · 2021-07-13T17:40:28.000-05:00
diff --git a/src/libraries/System.Text.Json/ref/System.Text.Json.cs b/src/libraries/System.Text.Json/ref/System.Text.Json.cs
@@ -832,6 +832,12 @@ public sealed partial class JsonPropertyNameAttribute : System.Text.Json.Seriali
         public JsonPropertyNameAttribute(string name) { }
         public string Name { get { throw null; } }
     }
+    [System.AttributeUsageAttribute(System.AttributeTargets.Field | System.AttributeTargets.Property, AllowMultiple = false)]
+    public sealed partial class JsonPropertyOrderAttribute : System.Text.Json.Serialization.JsonAttribute
+    {
+        public JsonPropertyOrderAttribute(int order) { }
+        public int Order { get { throw null; } }
+    }
     [System.AttributeUsageAttribute(System.AttributeTargets.Class, AllowMultiple=true)]
     public sealed partial class JsonSerializableAttribute : System.Text.Json.Serialization.JsonAttribute
     {
diff --git a/src/libraries/System.Text.Json/src/System.Text.Json.csproj b/src/libraries/System.Text.Json/src/System.Text.Json.csproj
@@ -22,7 +22,7 @@
     <Compile Include="..\Common\JsonCamelCaseNamingPolicy.cs" Link="Common\System\Text\Json\JsonCamelCaseNamingPolicy.cs" />
     <Compile Include="..\Common\JsonNamingPolicy.cs" Link="Common\System\Text\Json\JsonNamingPolicy.cs" />
     <Compile Include="..\Common\JsonAttribute.cs" Link="Common\System\Text\Json\Serialization\JsonAttribute.cs" />
-    <Compile Include="..\Common\JsonHelpers.cs" Link ="Common\System\Text\Json\JsonHelpers.cs" />
+    <Compile Include="..\Common\JsonHelpers.cs" Link="Common\System\Text\Json\JsonHelpers.cs" />
     <Compile Include="..\Common\JsonIgnoreCondition.cs" Link="Common\System\Text\Json\Serialization\JsonIgnoreCondition.cs" />
     <Compile Include="..\Common\JsonKnownNamingPolicy.cs" Link="Common\System\Text\Json\Serialization\JsonKnownNamingPolicy.cs" />
     <Compile Include="..\Common\JsonNumberHandling.cs" Link="Common\System\Text\Json\Serialization\JsonNumberHandling.cs" />
@@ -89,6 +89,7 @@
     <Compile Include="System\Text\Json\Serialization\Attributes\JsonIncludeAttribute.cs" />
     <Compile Include="System\Text\Json\Serialization\Attributes\JsonNumberHandlingAttribute.cs" />
     <Compile Include="System\Text\Json\Serialization\Attributes\JsonPropertyNameAttribute.cs" />
+    <Compile Include="System\Text\Json\Serialization\Attributes\JsonPropertyOrderAttribute.cs" />
     <Compile Include="System\Text\Json\Serialization\Converters\JsonMetadataServicesConverter.cs" />
     <Compile Include="System\Text\Json\Serialization\IgnoreReferenceResolver.cs" />
     <Compile Include="System\Text\Json\Serialization\IJsonOnDeserialized.cs" />
diff --git a/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Attributes/JsonPropertyOrderAttribute.cs b/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Attributes/JsonPropertyOrderAttribute.cs
@@ -0,0 +1,28 @@
+﻿// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace System.Text.Json.Serialization
+{
+    /// <summary>
+    /// Specifies the property order that is present in the JSON when serializing. Lower values are serialized first.
+    /// If the attribute is not specified, the default value is 0.
+    /// </summary>
+    /// <remarks>If multiple properties have the same value, the ordering is undefined between them.</remarks>
+    [AttributeUsage(AttributeTargets.Property | AttributeTargets.Field, AllowMultiple = false)]
+    public sealed class JsonPropertyOrderAttribute : JsonAttribute
+    {
+        /// <summary>
+        /// Initializes a new instance of <see cref="JsonPropertyNameAttribute"/> with the specified order.
+        /// </summary>
+        /// <param name="order">The order of the property.</param>
+        public JsonPropertyOrderAttribute(int order)
+        {
+            Order = order;
+        }
+
+        /// <summary>
+        /// The serialization order of the property.
+        /// </summary>
+        public int Order { get; }
+    }
+}
diff --git a/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Metadata/JsonPropertyInfo.cs b/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Metadata/JsonPropertyInfo.cs
@@ -74,6 +74,12 @@ internal virtual void GetPolicies(JsonIgnoreCondition? ignoreCondition, JsonNumb
                 DeterminePropertyName();
                 DetermineIgnoreCondition(ignoreCondition);
 
+                JsonPropertyOrderAttribute? orderAttr = GetAttribute<JsonPropertyOrderAttribute>(MemberInfo);
+                if (orderAttr != null)
+                {
+                    Order = orderAttr.Order;
+                }
+
                 JsonNumberHandlingAttribute? attribute = GetAttribute<JsonNumberHandlingAttribute>(MemberInfo);
                 DetermineNumberHandlingForProperty(attribute?.Handling, declaringTypeNumberHandling);
             }
@@ -366,6 +372,11 @@ internal abstract void InitializeForTypeInfo(
 
         internal JsonSerializerOptions Options { get; set; } = null!; // initialized in Init method
 
+        /// <summary>
+        /// The property order.
+        /// </summary>
+        internal int Order { get; set; }
+
         internal bool ReadJsonAndAddExtensionProperty(
             object obj,
             ref ReadStack state,
diff --git a/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Metadata/JsonTypeInfo.cs b/src/libraries/System.Text.Json/src/System/Text/Json/Serialization/Metadata/JsonTypeInfo.cs
@@ -197,6 +197,8 @@ internal JsonTypeInfo(Type type, JsonConverter converter, Type runtimeType, Json
 
                         PropertyInfo[] properties = type.GetProperties(bindingFlags);
 
+                        bool propertyOrderSpecified = false;
+
                         // PropertyCache is not accessed by other threads until the current JsonTypeInfo instance
                         //  is finished initializing and added to the cache on JsonSerializerOptions.
                         // Default 'capacity' to the common non-polymorphic + property case.
@@ -229,6 +231,7 @@ internal JsonTypeInfo(Type type, JsonConverter converter, Type runtimeType, Json
                                         propertyInfo,
                                         isVirtual,
                                         typeNumberHandling,
+                                        ref propertyOrderSpecified,
                                         ref ignoredMembers);
                                 }
                                 else
@@ -263,6 +266,7 @@ internal JsonTypeInfo(Type type, JsonConverter converter, Type runtimeType, Json
                                             fieldInfo,
                                             isVirtual: false,
                                             typeNumberHandling,
+                                            ref propertyOrderSpecified,
                                             ref ignoredMembers);
                                     }
                                 }
@@ -286,6 +290,11 @@ internal JsonTypeInfo(Type type, JsonConverter converter, Type runtimeType, Json
                             properties = currentType.GetProperties(bindingFlags);
                         };
 
+                        if (propertyOrderSpecified)
+                        {
+                            PropertyCache.List.Sort((p1, p2) => p1.Value!.Order.CompareTo(p2.Value!.Order));
+                        }
+
                         if (converter.ConstructorIsParameterized)
                         {
                             InitializeConstructorParameters(converter.ConstructorInfo!);
@@ -327,6 +336,7 @@ private void CacheMember(
             MemberInfo memberInfo,
             bool isVirtual,
             JsonNumberHandling? typeNumberHandling,
+            ref bool propertyOrderSpecified,
             ref Dictionary<string, JsonPropertyInfo>? ignoredMembers)
         {
             bool hasExtensionAttribute = memberInfo.GetCustomAttribute(typeof(JsonExtensionDataAttribute)) != null;
@@ -347,6 +357,7 @@ private void CacheMember(
             else
             {
                 CacheMember(jsonPropertyInfo, PropertyCache, ref ignoredMembers);
+                propertyOrderSpecified |= jsonPropertyInfo.Order != 0;
             }
         }
 
diff --git a/src/libraries/System.Text.Json/tests/System.Text.Json.Tests/Serialization/PropertyOrderTests.cs b/src/libraries/System.Text.Json/tests/System.Text.Json.Tests/Serialization/PropertyOrderTests.cs
@@ -0,0 +1,68 @@
+﻿// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Xunit;
+
+namespace System.Text.Json.Serialization.Tests
+{
+    public static class PropertyOrderTests
+    {
+        private class MyPoco_BeforeAndAfter
+        {
+            public int B { get; set; }
+
+            [JsonPropertyOrder(1)]
+            public int A { get; set; }
+
+            [JsonPropertyOrder(-1)]
+            public int C { get; set; }
+        }
+
+        [Fact]
+        public static void BeforeAndAfterDefaultOrder()
+        {
+            string json = JsonSerializer.Serialize<MyPoco_BeforeAndAfter>(new MyPoco_BeforeAndAfter());
+            Assert.Equal("{\"C\":0,\"B\":0,\"A\":0}", json);
+        }
+
+        private class MyPoco_After
+        {
+            [JsonPropertyOrder(2)]
+            public int C { get; set; }
+
+            public int B { get; set; }
+            public int D { get; set; }
+
+            [JsonPropertyOrder(1)]
+            public int A { get; set; }
+        }
+
+        [Fact]
+        public static void AfterDefaultOrder()
+        {
+            string json = JsonSerializer.Serialize<MyPoco_After>(new MyPoco_After());
+            Assert.EndsWith("\"A\":0,\"C\":0}", json);
+            // Order of B and D are not defined except they come before A and C
+        }
+
+        private class MyPoco_Before
+        {
+            [JsonPropertyOrder(-1)]
+            public int C { get; set; }
+
+            public int B { get; set; }
+            public int D { get; set; }
+
+            [JsonPropertyOrder(-2)]
+            public int A { get; set; }
+        }
+
+        [Fact]
+        public static void BeforeDefaultOrder()
+        {
+            string json = JsonSerializer.Serialize<MyPoco_Before>(new MyPoco_Before());
+            Assert.StartsWith("{\"A\":0,\"C\":0", json);
+            // Order of B and D are not defined except they come after A and C
+        }
+    }
+}
diff --git a/src/libraries/System.Text.Json/tests/System.Text.Json.Tests/System.Text.Json.Tests.csproj b/src/libraries/System.Text.Json/tests/System.Text.Json.Tests/System.Text.Json.Tests.csproj
@@ -166,6 +166,7 @@
     <Compile Include="Serialization\OptionsTests.cs" />
     <Compile Include="Serialization\PolymorphicTests.cs" />
     <Compile Include="Serialization\PropertyNameTests.cs" />
+    <Compile Include="Serialization\PropertyOrderTests.cs" />
     <Compile Include="Serialization\PropertyVisibilityTests.cs" />
     <Compile Include="Serialization\ReadScenarioTests.cs" />
     <Compile Include="Serialization\ReadValueTests.cs" />

Original file line number	Diff line number	Diff line change
`@@ -832,6 +832,12 @@ public sealed partial class JsonPropertyNameAttribute : System.Text.Json.Seriali`
`832`	`832`	`public JsonPropertyNameAttribute(string name) { }`
`833`	`833`	`public string Name { get { throw null; } }`
`834`	`834`	`}`
	`835`	`+ [System.AttributeUsageAttribute(System.AttributeTargets.Field \| System.AttributeTargets.Property, AllowMultiple = false)]`
	`836`	`+ public sealed partial class JsonPropertyOrderAttribute : System.Text.Json.Serialization.JsonAttribute`
	`837`	`+ {`
	`838`	`+ public JsonPropertyOrderAttribute(int order) { }`
	`839`	`+ public int Order { get { throw null; } }`
	`840`	`+ }`
`835`	`841`	`[System.AttributeUsageAttribute(System.AttributeTargets.Class, AllowMultiple=true)]`
`836`	`842`	`public sealed partial class JsonSerializableAttribute : System.Text.Json.Serialization.JsonAttribute`
`837`	`843`	`{`
Original file line number	Diff line number	Diff line change
`@@ -197,6 +197,8 @@ internal JsonTypeInfo(Type type, JsonConverter converter, Type runtimeType, Json`
`197`	`197`
`198`	`198`	`PropertyInfo[] properties = type.GetProperties(bindingFlags);`
`199`	`199`
	`200`	`+ bool propertyOrderSpecified = false;`
	`201`	`+`
`200`	`202`	`// PropertyCache is not accessed by other threads until the current JsonTypeInfo instance`
`201`	`203`	`// is finished initializing and added to the cache on JsonSerializerOptions.`
`202`	`204`	`// Default 'capacity' to the common non-polymorphic + property case.`
`@@ -229,6 +231,7 @@ internal JsonTypeInfo(Type type, JsonConverter converter, Type runtimeType, Json`
`229`	`231`	`propertyInfo,`
`230`	`232`	`isVirtual,`
`231`	`233`	`typeNumberHandling,`
	`234`	`+ ref propertyOrderSpecified,`
`232`	`235`	`ref ignoredMembers);`
`233`	`236`	`}`
`234`	`237`	`else`
`@@ -263,6 +266,7 @@ internal JsonTypeInfo(Type type, JsonConverter converter, Type runtimeType, Json`
`263`	`266`	`fieldInfo,`
`264`	`267`	`isVirtual: false,`
`265`	`268`	`typeNumberHandling,`
	`269`	`+ ref propertyOrderSpecified,`
`266`	`270`	`ref ignoredMembers);`
`267`	`271`	`}`
`268`	`272`	`}`
`@@ -286,6 +290,11 @@ internal JsonTypeInfo(Type type, JsonConverter converter, Type runtimeType, Json`
`286`	`290`	`properties = currentType.GetProperties(bindingFlags);`
`287`	`291`	`};`
`288`	`292`
	`293`	`+ if (propertyOrderSpecified)`
	`294`	`+ {`
	`295`	`+ PropertyCache.List.Sort((p1, p2) => p1.Value!.Order.CompareTo(p2.Value!.Order));`
	`296`	`+ }`
	`297`	`+`
`289`	`298`	`if (converter.ConstructorIsParameterized)`
`290`	`299`	`{`
`291`	`300`	`InitializeConstructorParameters(converter.ConstructorInfo!);`
`@@ -327,6 +336,7 @@ private void CacheMember(`
`327`	`336`	`MemberInfo memberInfo,`
`328`	`337`	`bool isVirtual,`
`329`	`338`	`JsonNumberHandling? typeNumberHandling,`
	`339`	`+ ref bool propertyOrderSpecified,`
`330`	`340`	`ref Dictionary<string, JsonPropertyInfo>? ignoredMembers)`
`331`	`341`	`{`
`332`	`342`	`bool hasExtensionAttribute = memberInfo.GetCustomAttribute(typeof(JsonExtensionDataAttribute)) != null;`
`@@ -347,6 +357,7 @@ private void CacheMember(`
`347`	`357`	`else`
`348`	`358`	`{`
`349`	`359`	`CacheMember(jsonPropertyInfo, PropertyCache, ref ignoredMembers);`
	`360`	`+ propertyOrderSpecified \|= jsonPropertyInfo.Order != 0;`
`350`	`361`	`}`
`351`	`362`	`}`
`352`	`363`