Fixed ability to skip interface implementations and union cases in query

src/FSharp.Data.GraphQL.Server/Execution.fs

@@ -256,7 +256,12 @@ let private resolveField (execute: ExecuteField) (ctx: ResolveFieldContext) (par
 
 type ResolverResult<'T> = Result<'T * IObservable<GQLDeferredResponseContent> option * GQLProblemDetails list, GQLProblemDetails list>
 
+[<RequireQualifiedAccess>]
 module ResolverResult =
+
+    let data data  = Ok (data, None, [])
+    let defered data deferred = Ok (data, Some deferred, [])
+
     let mapValue (f : 'T -> 'U) (r : ResolverResult<'T>) : ResolverResult<'U> =
         Result.map(fun (data, deferred, errs) -> (f data, deferred, errs)) r
 
@@ -280,7 +285,7 @@ let private unionImplError unionName tyName path ctx = resolverError path ctx (G
 let private deferredNullableError name tyName path ctx = resolverError path ctx (GQLMessageException (sprintf "Deferred field %s of type '%s' must be nullable" name tyName))
 let private streamListError name tyName path ctx = resolverError path ctx (GQLMessageException (sprintf "Streamed field %s of type '%s' must be list" name tyName))
 
-let private resolved name v : AsyncVal<ResolverResult<KeyValuePair<string, obj>>> = AsyncVal.wrap <| Ok(KeyValuePair(name, box v), None, [])
+let private resolved name v : AsyncVal<ResolverResult<KeyValuePair<string, obj>>> = KeyValuePair(name, box v) |> ResolverResult.data |> AsyncVal.wrap
 
 let deferResults path (res : ResolverResult<obj>) : IObservable<GQLDeferredResponseContent> =
     let formattedPath = path |> List.rev
@@ -370,7 +375,7 @@ let rec private direct (returnDef : OutputDef) (ctx : ResolveFieldContext) (path
             | kind -> failwithf "Unexpected value of ctx.ExecutionPlan.Kind: %A" kind
         match Map.tryFind resolvedDef.Name typeMap with
         | Some fields -> executeObjectFields fields name resolvedDef ctx path value
-        | None -> raiseErrors <| interfaceImplError iDef.Name resolvedDef.Name path ctx
+        | None -> KeyValuePair(name, obj()) |> ResolverResult.data |> AsyncVal.wrap
 
     | Union uDef ->
         let possibleTypesFn = ctx.Schema.GetPossibleTypes
@@ -382,7 +387,7 @@ let rec private direct (returnDef : OutputDef) (ctx : ResolveFieldContext) (path
             | kind -> failwithf "Unexpected value of ctx.ExecutionPlan.Kind: %A" kind
         match Map.tryFind resolvedDef.Name typeMap with
         | Some fields -> executeObjectFields fields name resolvedDef ctx path (uDef.ResolveValue value)
-        | None -> raiseErrors <| unionImplError uDef.Name resolvedDef.Name path ctx
+        | None -> KeyValuePair(name, obj()) |> ResolverResult.data |> AsyncVal.wrap
 
     | _ -> failwithf "Unexpected value of returnDef: %O" returnDef
 
@@ -393,7 +398,7 @@ and deferred (ctx : ResolveFieldContext) (path : FieldPath) (parent : obj) (valu
         executeResolvers ctx path parent (toOption value |> AsyncVal.wrap)
         |> Observable.ofAsyncVal
         |> Observable.bind(ResolverResult.mapValue(fun d -> d.Value) >> deferResults path)
-    AsyncVal.wrap <| Ok(KeyValuePair(info.Identifier, null), Some deferred, [])
+    ResolverResult.defered (KeyValuePair (info.Identifier, null)) deferred |> AsyncVal.wrap
 
 and private streamed (options : BufferedStreamOptions) (innerDef : OutputDef) (ctx : ResolveFieldContext) (path : FieldPath) (parent : obj) (value : obj) =
     let info = ctx.ExecutionInfo
@@ -444,7 +449,7 @@ and private streamed (options : BufferedStreamOptions) (innerDef : OutputDef) (c
             |> Array.mapi resolveItem
             |> Observable.ofAsyncValSeq
             |> buffer
-        AsyncVal.wrap <| Ok(KeyValuePair(info.Identifier, box [||]), Some stream, [])
+        ResolverResult.defered (KeyValuePair (info.Identifier, box [])) stream |> AsyncVal.wrap
     | _ -> raise <| GQLMessageException (ErrorMessages.expectedEnumerableValue ctx.ExecutionInfo.Identifier (value.GetType()))
 
 and private live (ctx : ResolveFieldContext) (path : FieldPath) (parent : obj) (value : obj) =
@@ -510,12 +515,12 @@ and private executeResolvers (ctx : ResolveFieldContext) (path : FieldPath) (par
     match info.Kind, returnDef with
     | ResolveDeferred innerInfo, _ when innerInfo.IsNullable -> // We can only defer nullable fields
         deferred
-        |> resolveWith { ctx with ExecutionInfo = { innerInfo with IsNullable = false } }
+        |> resolveWith { ctx with ExecutionInfo = innerInfo }
     | ResolveDeferred innerInfo, _ ->
         raiseErrors <| deferredNullableError (innerInfo.Identifier) (innerInfo.ReturnDef.ToString()) path ctx
     | ResolveStreamed (innerInfo, mode), HasList innerDef -> // We can only stream lists
         streamed mode innerDef
-        |> resolveWith { ctx with ExecutionInfo = innerInfo; }
+        |> resolveWith { ctx with ExecutionInfo = innerInfo }
     | ResolveStreamed (innerInfo, _), _ ->
         raiseErrors <| streamListError innerInfo.Identifier (returnDef.ToString()) path ctx
     | ResolveLive innerInfo, _ ->

src/FSharp.Data.GraphQL.Server/IO.fs

@@ -61,9 +61,9 @@ type GQLExecutionResult =
     static member Invalid(documentId, errors, meta) =
         GQLExecutionResult.RequestError(documentId, errors, meta)
     static member ErrorAsync(documentId, msg : string, meta) =
-        asyncVal.Return (GQLExecutionResult.Error (documentId, msg, meta))
+        AsyncVal.wrap (GQLExecutionResult.Error (documentId, msg, meta))
     static member ErrorAsync(documentId, error : IGQLError, meta) =
-        asyncVal.Return (GQLExecutionResult.Error (documentId, error, meta))
+        AsyncVal.wrap (GQLExecutionResult.Error (documentId, error, meta))
 
 // TODO: Rename to PascalCase
 and GQLResponseContent =

tests/FSharp.Data.GraphQL.Tests/AbstractionTests.fs

@@ -75,7 +75,7 @@ let schemaWithInterface =
                             [ Define.Field (
                                   "pets",
                                   ListOf PetType,
-                                  fun _ _ -> [ { Name = "Odie"; Woofs = true } :> IPet; upcast { Name = "Garfield"; Meows = false } ]
+                                  fun _ _ -> [ { Name = "Odie"; Woofs = true } :> IPet; { Name = "Garfield"; Meows = false } ]
                               ) ]
                     ),
                 config = { SchemaConfig.Default with Types = [ CatType; DogType ] }
@@ -111,6 +111,48 @@ let ``Execute handles execution of abstract types: isTypeOf is used to resolve r
         empty errors
         data |> equals (upcast expected)
 
+[<Fact>]
+let ``Execute handles execution of abstract types: not specified Interface types must be empty objects`` () =
+    let query =
+        """{
+      pets {
+        ... on Dog {
+          name
+          woofs
+        }
+      }
+    }"""
+
+    let result = sync <| schemaWithInterface.Value.AsyncExecute (parse query)
+
+    let expected = NameValueLookup.ofList [ "name", "Odie" :> obj; "woofs", upcast true ]
+
+    ensureDirect result <| fun data errors ->
+        empty errors
+        let [| dog; emptyObj |] = data["pets"] :?> obj array
+        dog |> equals (upcast expected)
+        emptyObj.GetType() |> equals typeof<obj>
+
+    let query =
+        """{
+      pets {
+        ... on Cat {
+          name
+          meows
+        }
+      }
+    }"""
+
+    let result = sync <| schemaWithInterface.Value.AsyncExecute (parse query)
+
+    let expected = NameValueLookup.ofList [ "name", "Garfield" :> obj; "meows", upcast false ]
+
+    ensureDirect result <| fun data errors ->
+        empty errors
+        let [| emptyObj; cat|] = data["pets"] :?> obj array
+        cat |> equals (upcast expected)
+        emptyObj.GetType() |> equals typeof<obj>
+
 [<Fact>]
 let ``Execute handles execution of abstract types: absent field resolution produces errors for Interface`` () =
     let query =
@@ -155,6 +197,26 @@ let ``Execute handles execution of abstract types: absent type resolution produc
         catError |> ensureValidationError "Field 'unknownField2' is not defined in schema type 'Cat'." [ "pets"; "unknownField2" ]
         dogError |> ensureValidationError "Inline fragment has type condition 'UnknownDog', but that type does not exist in the schema." [ "pets" ]
 
+    let query =
+        """{
+      pets {
+        name
+        ... on Dog {
+          woofs
+          unknownField1
+        }
+        ... on UnknownCat {
+          meows
+          unknownField2
+        }
+      }
+    }"""
+
+    let result = sync <| schemaWithInterface.Value.AsyncExecute (parse query)
+    ensureRequestError result <| fun [ catError; dogError ] ->
+        catError |> ensureValidationError "Field 'unknownField1' is not defined in schema type 'Dog'." [ "pets"; "unknownField1" ]
+        dogError |> ensureValidationError "Inline fragment has type condition 'UnknownCat', but that type does not exist in the schema." [ "pets" ]
+
 
 let schemaWithUnion =
     lazy
@@ -219,6 +281,48 @@ let ``Execute handles execution of abstract types: isTypeOf is used to resolve r
         empty errors
         data |> equals (upcast expected)
 
+[<Fact>]
+let ``Execute handles execution of abstract types: not specified Union types must be empty objects`` () =
+    let query =
+        """{
+      pets {
+        ... on Dog {
+          name
+          woofs
+        }
+      }
+    }"""
+
+    let result = sync <| schemaWithUnion.Value.AsyncExecute (parse query)
+
+    let expected = NameValueLookup.ofList [ "name", "Odie" :> obj; "woofs", upcast true ]
+
+    ensureDirect result <| fun data errors ->
+        empty errors
+        let [| dog; emptyObj |] = data["pets"] :?> obj array
+        dog |> equals (upcast expected)
+        emptyObj.GetType() |> equals typeof<obj>
+
+    let query =
+        """{
+      pets {
+        ... on Cat {
+          name
+          meows
+        }
+      }
+    }"""
+
+    let result = sync <| schemaWithUnion.Value.AsyncExecute (parse query)
+
+    let expected = NameValueLookup.ofList [ "name", "Garfield" :> obj; "meows", upcast false ]
+
+    ensureDirect result <| fun data errors ->
+        empty errors
+        let [| emptyObj; cat|] = data["pets"] :?> obj array
+        cat |> equals (upcast expected)
+        emptyObj.GetType() |> equals typeof<obj>
+
 [<Fact>]
 let ``Execute handles execution of abstract types: absent field resolution produces errors for Union`` () =
     let query =

tests/FSharp.Data.GraphQL.Tests/Helpers and Extensions/AsyncValTests.fs

@@ -72,14 +72,14 @@ let ``AsyncVal computation defines zero value`` () =
 
 [<Fact>]
 let ``AsyncVal can be returned from Async computation`` () =
-    let a = async { return! asyncVal.Return 1 }
+    let a = async { return! AsyncVal.wrap 1 }
     let res = a |> sync
     res |> equals 1
 
 [<Fact>]
 let ``AsyncVal can be bound inside Async computation`` () =
     let a = async {
-        let! v = asyncVal.Return 1
+        let! v = AsyncVal.wrap 1
         return v }
     let res = a |> sync
     res |> equals 1