feat: add WithOverrideMembers for record fields

Author: Tarmil

src/FSharp.SystemTextJson/Options.fs

@@ -185,6 +185,7 @@ type internal JsonFSharpOptionsRecord =
       MapFormat: MapFormat
       Types: JsonFSharpTypes
       AllowOverride: bool
+      OverrideMembers: IDictionary<string, seq<Attribute>>
       Overrides: JsonFSharpOptions -> IDictionary<Type, JsonFSharpOptions> }
 
 and JsonFSharpOptions internal (options: JsonFSharpOptionsRecord) =
@@ -224,6 +225,7 @@ and JsonFSharpOptions internal (options: JsonFSharpOptionsRecord) =
               MapFormat = MapFormat.ObjectOrArrayOfPairs
               Types = types
               AllowOverride = allowOverride
+              OverrideMembers = Map.empty
               Overrides = emptyOverrides }
         )
 
@@ -340,6 +342,9 @@ and JsonFSharpOptions internal (options: JsonFSharpOptionsRecord) =
     member _.WithOverrides(overrides) =
         JsonFSharpOptions({ options with Overrides = fun _ -> overrides })
 
+    member _.WithOverrideMembers(overrides) =
+        JsonFSharpOptions({ options with OverrideMembers = overrides })
+
     member private this.WithUnionEncodingFlag(flag, set) =
         if set then
             this.WithUnionEncoding(options.UnionEncoding ||| flag)

src/FSharp.SystemTextJson/Record.fs

@@ -8,6 +8,7 @@ open FSharp.Reflection
 open System.Text.Json.Serialization.Helpers
 
 type private RecordField
+    private
     (
         fsOptions: JsonFSharpOptionsRecord,
         options: JsonSerializerOptions,
@@ -37,7 +38,18 @@ type private RecordField
 
     new(fsOptions, options: JsonSerializerOptions, i, p: PropertyInfo, fieldOrderIndices) =
         let names =
-            match getJsonNames "field" (fun ty -> p.GetCustomAttributes(ty, true)) with
+            match
+                getJsonNames
+                    "field"
+                    (fun ty ->
+                        match fsOptions.OverrideMembers.TryGetValue(p.Name) with
+                        | true, attrs ->
+                            [| for attr in attrs do
+                                   if attr.GetType().IsAssignableFrom(ty) then
+                                       box attr |]
+                        | false, _ -> p.GetCustomAttributes(ty, true)
+                    )
+            with
             | ValueSome names -> names |> Array.map (fun n -> n.AsString())
             | ValueNone -> [| convertName options.PropertyNamingPolicy p.Name |]
         RecordField(fsOptions, options, i, p, fieldOrderIndices, names)

tests/FSharp.SystemTextJson.Tests/Test.Record.fs

@@ -497,6 +497,26 @@ module NonStruct =
             JsonSerializer.Serialize({ incX = 1; incY = "a" }, dontIncludeRecordPropertiesOptions)
         Assert.Equal("""{"incX":1,"incY":"a","incZ":42}""", actual)
 
+    type OverrideMembersRecord = { x: int; y: string }
+
+    let overrideMembersOptions =
+        JsonFSharpOptions()
+            .WithOverrides(fun o ->
+                dict [ typeof<OverrideMembersRecord>, o.WithOverrideMembers(dict [ "x", [ JsonNameAttribute("z") ] ]) ]
+            )
+            .ToJsonSerializerOptions()
+
+    [<Fact>]
+    let ``serialize with OverrideMembers`` () =
+        let actual = JsonSerializer.Serialize({ x = 1; y = "b" }, overrideMembersOptions)
+        Assert.Equal("""{"z":1,"y":"b"}""", actual)
+
+    [<Fact>]
+    let ``deserialize with OverrideMembers`` () =
+        let actual =
+            JsonSerializer.Deserialize<OverrideMembersRecord>("""{"z":1,"y":"b"}""", overrideMembersOptions)
+        Assert.Equal({ x = 1; y = "b" }, actual)
+
 module Struct =
 
     [<Struct; JsonFSharpConverter>]
@@ -943,3 +963,24 @@ module Struct =
         let actual =
             JsonSerializer.Serialize({ incX = 1; incY = "a" }, dontIncludeRecordPropertiesOptions)
         Assert.Equal("""{"incX":1,"incY":"a","incZ":42}""", actual)
+
+    [<Struct>]
+    type OverrideMembersRecord = { x: int; y: string }
+
+    let overrideMembersOptions =
+        JsonFSharpOptions()
+            .WithOverrides(fun o ->
+                dict [ typeof<OverrideMembersRecord>, o.WithOverrideMembers(dict [ "x", [ JsonNameAttribute("z") ] ]) ]
+            )
+            .ToJsonSerializerOptions()
+
+    [<Fact>]
+    let ``serialize with OverrideMembers`` () =
+        let actual = JsonSerializer.Serialize({ x = 1; y = "b" }, overrideMembersOptions)
+        Assert.Equal("""{"z":1,"y":"b"}""", actual)
+
+    [<Fact>]
+    let ``deserialize with OverrideMembers`` () =
+        let actual =
+            JsonSerializer.Deserialize<OverrideMembersRecord>("""{"z":1,"y":"b"}""", overrideMembersOptions)
+        Assert.Equal({ x = 1; y = "b" }, actual)