optional return pointers in unmarshalInput (#2397)

* optional return pointers in unmarshalInput

* add docs for return_pointers_in_unmarshalinput

codegen/config/binder.go

@@ -183,15 +183,16 @@ func (b *Binder) PointerTo(ref *TypeReference) *TypeReference {
 
 // TypeReference is used by args and field types. The Definition can refer to both input and output types.
 type TypeReference struct {
-	Definition  *ast.Definition
-	GQL         *ast.Type
-	GO          types.Type  // Type of the field being bound. Could be a pointer or a value type of Target.
-	Target      types.Type  // The actual type that we know how to bind to. May require pointer juggling when traversing to fields.
-	CastType    types.Type  // Before calling marshalling functions cast from/to this base type
-	Marshaler   *types.Func // When using external marshalling functions this will point to the Marshal function
-	Unmarshaler *types.Func // When using external marshalling functions this will point to the Unmarshal function
-	IsMarshaler bool        // Does the type implement graphql.Marshaler and graphql.Unmarshaler
-	IsContext   bool        // Is the Marshaler/Unmarshaller the context version; applies to either the method or interface variety.
+	Definition              *ast.Definition
+	GQL                     *ast.Type
+	GO                      types.Type  // Type of the field being bound. Could be a pointer or a value type of Target.
+	Target                  types.Type  // The actual type that we know how to bind to. May require pointer juggling when traversing to fields.
+	CastType                types.Type  // Before calling marshalling functions cast from/to this base type
+	Marshaler               *types.Func // When using external marshalling functions this will point to the Marshal function
+	Unmarshaler             *types.Func // When using external marshalling functions this will point to the Unmarshal function
+	IsMarshaler             bool        // Does the type implement graphql.Marshaler and graphql.Unmarshaler
+	IsContext               bool        // Is the Marshaler/Unmarshaller the context version; applies to either the method or interface variety.
+	PointersInUmarshalInput bool        // Inverse values and pointers in return.
 }
 
 func (ref *TypeReference) Elem() *TypeReference {
@@ -412,6 +413,8 @@ func (b *Binder) TypeReference(schemaType *ast.Type, bindTarget types.Type) (ret
 			ref.GO = bindTarget
 		}
 
+		ref.PointersInUmarshalInput = b.cfg.ReturnPointersInUmarshalInput
+
 		return ref, nil
 	}
 

codegen/config/config.go

@@ -28,6 +28,7 @@ type Config struct {
 	OmitSliceElementPointers      bool                       `yaml:"omit_slice_element_pointers,omitempty"`
 	OmitGetters                   bool                       `yaml:"omit_getters,omitempty"`
 	StructFieldsAlwaysPointers    bool                       `yaml:"struct_fields_always_pointers,omitempty"`
+	ReturnPointersInUmarshalInput bool                       `yaml:"return_pointers_in_unmarshalinput,omitempty"`
 	ResolversAlwaysReturnPointers bool                       `yaml:"resolvers_always_return_pointers,omitempty"`
 	SkipValidation                bool                       `yaml:"skip_validation,omitempty"`
 	SkipModTidy                   bool                       `yaml:"skip_mod_tidy,omitempty"`
@@ -50,6 +51,7 @@ func DefaultConfig() *Config {
 		Directives:                    map[string]DirectiveConfig{},
 		Models:                        TypeMap{},
 		StructFieldsAlwaysPointers:    true,
+		ReturnPointersInUmarshalInput: false,
 		ResolversAlwaysReturnPointers: true,
 	}
 }

codegen/input.gotpl

@@ -1,6 +1,10 @@
 {{- range $input := .Inputs }}
 	{{- if not .HasUnmarshal }}
-	func (ec *executionContext) unmarshalInput{{ .Name }}(ctx context.Context, obj interface{}) ({{.Type | ref}}, error) {
+	{{- $it := "it" }}
+	{{- if .PointersInUmarshalInput }}
+	  {{- $it = "&it" }}
+	{{- end }}
+	func (ec *executionContext) unmarshalInput{{ .Name }}(ctx context.Context, obj interface{}) ({{ if .PointersInUmarshalInput }}*{{ end }}{{.Type | ref}}, error) {
 		var it {{.Type | ref}}
 		asMap := map[string]interface{}{}
 		for k, v := range obj.(map[string]interface{}) {
@@ -31,12 +35,12 @@
 					{{ template "implDirectives" $field }}
 					tmp, err := directive{{$field.ImplDirectives|len}}(ctx)
 					if err != nil {
-						return it, graphql.ErrorOnPath(ctx, err)
+						return {{$it}}, graphql.ErrorOnPath(ctx, err)
 					}
 					if data, ok := tmp.({{ $field.TypeReference.GO | ref }}) ; ok {
 						{{- if $field.IsResolver }}
 							if err = ec.resolvers.{{ $field.ShortInvocation }}; err != nil {
-								return it, err
+								return {{$it}}, err
 							}
 						{{- else }}
 							it.{{$field.GoFieldName}} = data
@@ -49,29 +53,29 @@
 					{{- end }}
 					} else {
 						err := fmt.Errorf(`unexpected type %T from directive, should be {{ $field.TypeReference.GO }}`, tmp)
-						return it, graphql.ErrorOnPath(ctx, err)
+						return {{$it}}, graphql.ErrorOnPath(ctx, err)
 					}
 				{{- else }}
 					{{- if $field.IsResolver }}
 						data, err := ec.{{ $field.TypeReference.UnmarshalFunc }}(ctx, v)
 						if err != nil {
-							return it, err
+							return {{$it}}, err
 						}
 						if err = ec.resolvers.{{ $field.ShortInvocation }}; err != nil {
-							return it, err
+							return {{$it}}, err
 						}
 					{{- else }}
 						it.{{$field.GoFieldName}}, err = ec.{{ $field.TypeReference.UnmarshalFunc }}(ctx, v)
 						if err != nil {
-							return it, err
+							return {{$it}}, err
 						}
 					{{- end }}
 				{{- end }}
 			{{- end }}
 			}
 		}
 
-		return it, nil
+		return {{$it}}, nil
 	}
 	{{- end }}
 {{ end }}

codegen/object.go

@@ -25,14 +25,15 @@ const (
 type Object struct {
 	*ast.Definition
 
-	Type               types.Type
-	ResolverInterface  types.Type
-	Root               bool
-	Fields             []*Field
-	Implements         []*ast.Definition
-	DisableConcurrency bool
-	Stream             bool
-	Directives         []*Directive
+	Type                    types.Type
+	ResolverInterface       types.Type
+	Root                    bool
+	Fields                  []*Field
+	Implements              []*ast.Definition
+	DisableConcurrency      bool
+	Stream                  bool
+	Directives              []*Directive
+	PointersInUmarshalInput bool
 }
 
 func (b *builder) buildObject(typ *ast.Definition) (*Object, error) {
@@ -42,11 +43,12 @@ func (b *builder) buildObject(typ *ast.Definition) (*Object, error) {
 	}
 	caser := cases.Title(language.English, cases.NoLower)
 	obj := &Object{
-		Definition:         typ,
-		Root:               b.Schema.Query == typ || b.Schema.Mutation == typ || b.Schema.Subscription == typ,
-		DisableConcurrency: typ == b.Schema.Mutation,
-		Stream:             typ == b.Schema.Subscription,
-		Directives:         dirs,
+		Definition:              typ,
+		Root:                    b.Schema.Query == typ || b.Schema.Mutation == typ || b.Schema.Subscription == typ,
+		DisableConcurrency:      typ == b.Schema.Mutation,
+		Stream:                  typ == b.Schema.Subscription,
+		Directives:              dirs,
+		PointersInUmarshalInput: b.Config.ReturnPointersInUmarshalInput,
 		ResolverInterface: types.NewNamed(
 			types.NewTypeName(0, b.Config.Exec.Pkg(), caser.String(typ.Name)+"Resolver", nil),
 			nil,

codegen/type.gotpl

@@ -75,9 +75,11 @@
 					return res, graphql.ErrorOnPath(ctx, err)
 				{{- else }}
 					res, err := ec.unmarshalInput{{ $type.GQL.Name }}(ctx, v)
-					{{- if $type.IsNilable }}
+					{{- if and $type.IsNilable (not $type.PointersInUmarshalInput) }}
 						return &res, graphql.ErrorOnPath(ctx, err)
-					{{- else}}
+					{{- else if and (not $type.IsNilable) $type.PointersInUmarshalInput }}
+						return *res, graphql.ErrorOnPath(ctx, err)
+					{{- else }}
 						return res, graphql.ErrorOnPath(ctx, err)
 					{{- end }}
 				{{- end }}

docs/content/config.md

@@ -51,6 +51,9 @@ resolver:
 # Optional: turn off to make resolvers return values instead of pointers for structs
 # resolvers_always_return_pointers: true
 
+# Optional: turn on to return pointers instead of values in unmarshalInput
+# return_pointers_in_unmarshalinput: false
+
 # Optional: set to speed up generation time by not performing a final validation pass.
 # skip_validation: true