[#180] Allow overriding generic types

Tarmil · Mar 30, 2024 · befd95a · befd95a
1 parent 1b6dbd9
commit befd95a
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Showing 2 changed files with 46 additions and 3 deletions.
diff --git a/src/FSharp.SystemTextJson/Helpers.fs b/src/FSharp.SystemTextJson/Helpers.fs
@@ -133,9 +133,19 @@ let overrideOptions (ty: Type) (defaultOptions: JsonFSharpOptions) =
     if isNull overrides then
         applyAttributeOverride ()
     else
-        match overrides.TryGetValue(ty) with
-        | true, options -> options |> inheritUnionEncoding
-        | false, _ -> applyAttributeOverride ()
+        let overrideOpt =
+            let mutable options = Unchecked.defaultof<_>
+            if
+                overrides.TryGetValue(ty, &options)
+                || (ty.IsGenericType
+                    && overrides.TryGetValue(ty.GetGenericTypeDefinition(), &options))
+            then
+                ValueSome options
+            else
+                ValueNone
+        match overrideOpt with
+        | ValueSome options -> options |> inheritUnionEncoding
+        | ValueNone -> applyAttributeOverride ()
 
 let isWrappedString (ty: Type) =
     TypeCache.isUnion ty

diff --git a/tests/FSharp.SystemTextJson.Tests/Test.Union.fs b/tests/FSharp.SystemTextJson.Tests/Test.Union.fs
@@ -1248,6 +1248,39 @@ module NonStruct =
                 .ToJsonSerializerOptions()
         Assert.Equal("""{"tag2":"A","x":123,"y":"abc"}""", JsonSerializer.Serialize(Override.A(123, "abc"), o))
 
+    [<Fact>]
+    let ``should apply explicit overrides on generic type`` () =
+        let o =
+            JsonFSharpOptions
+                .Default()
+                .WithUnionInternalTag()
+                .WithUnionNamedFields()
+                .WithOverrides(fun o -> dict [ typedefof<Result<_, _>>, o.WithUnionTagName("Result") ])
+                .ToJsonSerializerOptions()
+        Assert.Equal("""{"Result":"Ok","ResultValue":"abc"}""", JsonSerializer.Serialize(Ok "abc", o))
+
+    [<Fact>]
+    let ``should apply explicit override on specific type over generic type`` () =
+        let o =
+            JsonFSharpOptions
+                .Default()
+                .WithUnionInternalTag()
+                .WithUnionNamedFields()
+                .WithOverrides(fun o ->
+                    dict
+                        [ typeof<Result<string, string>>, o.WithUnionTagName("SpecificResult")
+                          typedefof<Result<_, _>>, o.WithUnionTagName("GenericResult") ]
+                )
+                .ToJsonSerializerOptions()
+        Assert.Equal(
+            """{"GenericResult":"Ok","ResultValue":42}""",
+            JsonSerializer.Serialize((Ok 42: Result<int, string>), o)
+        )
+        Assert.Equal(
+            """{"SpecificResult":"Ok","ResultValue":"abc"}""",
+            JsonSerializer.Serialize((Ok "abc": Result<string, string>), o)
+        )
+
     type NamedAfterTypesA = NTA of int
 
     type NamedAfterTypesB = NTB of int * string