Fix coercion of typedef primitives and their pointers. For example,

with "type MyInt int", values of type MyInt and *MyInt should be treated
as ints. Fixes graphql-go#488.

Author: atombender

scalars.go

@@ -3,12 +3,53 @@ package graphql
 import (
 	"fmt"
 	"math"
+	"reflect"
 	"strconv"
 	"time"
 
 	"github.com/graphql-go/graphql/language/ast"
 )
 
+func unwrapPrimitive(value interface{}) (interface{}, bool) {
+	r := reflect.Indirect(reflect.ValueOf(value))
+	if !r.IsValid() || (r.Kind() == reflect.Ptr && r.IsNil()) {
+		return nil, false
+	}
+
+	switch r.Kind() {
+	case reflect.Int:
+		return int(r.Int()), true
+	case reflect.Int8:
+		return int8(r.Int()), true
+	case reflect.Int16:
+		return int16(r.Int()), true
+	case reflect.Int32:
+		return int32(r.Int()), true
+	case reflect.Int64:
+		return r.Int(), true
+	case reflect.Uint:
+		return uint(r.Uint()), true
+	case reflect.Uint8:
+		return uint8(r.Uint()), true
+	case reflect.Uint16:
+		return uint16(r.Uint()), true
+	case reflect.Uint32:
+		return uint32(r.Uint()), true
+	case reflect.Uint64:
+		return r.Uint(), true
+	case reflect.Float32:
+		return float32(r.Float()), true
+	case reflect.Float64:
+		return r.Float(), true
+	case reflect.Bool:
+		return r.Bool(), true
+	case reflect.String:
+		return r.String(), true
+	default:
+		return nil, false
+	}
+}
+
 // As per the GraphQL Spec, Integers are only treated as valid when a valid
 // 32-bit signed integer, providing the broadest support across platforms.
 //
@@ -144,6 +185,10 @@ func coerceInt(value interface{}) interface{} {
 		return coerceInt(*value)
 	}
 
+	if v, ok := unwrapPrimitive(value); ok {
+		return coerceInt(v)
+	}
+
 	// If the value cannot be transformed into an int, return nil instead of '0'
 	// to denote 'no integer found'
 	return nil
@@ -276,6 +321,10 @@ func coerceFloat(value interface{}) interface{} {
 		return coerceFloat(*value)
 	}
 
+	if v, ok := unwrapPrimitive(value); ok {
+		return coerceFloat(v)
+	}
+
 	// If the value cannot be transformed into an float, return nil instead of '0.0'
 	// to denote 'no float found'
 	return nil
@@ -305,13 +354,23 @@ var Float = NewScalar(ScalarConfig{
 })
 
 func coerceString(value interface{}) interface{} {
-	if v, ok := value.(*string); ok {
-		if v == nil {
+	switch t := value.(type) {
+	case *string:
+		if t == nil {
 			return nil
 		}
-		return *v
+		return *t
+	case string:
+		return t
+	default:
+		if v, ok := unwrapPrimitive(value); ok {
+			return coerceString(v)
+		}
+		if r := reflect.ValueOf(value); r.Kind() == reflect.Ptr && r.IsNil() {
+			return nil
+		}
+		return fmt.Sprintf("%v", value)
 	}
-	return fmt.Sprintf("%v", value)
 }
 
 // String is the GraphQL string type definition
@@ -472,6 +531,13 @@ func coerceBool(value interface{}) interface{} {
 		}
 		return coerceBool(*value)
 	}
+
+	if v, ok := unwrapPrimitive(value); ok {
+		return coerceBool(v)
+	}
+	if r := reflect.ValueOf(value); r.Kind() == reflect.Ptr && r.IsNil() {
+		return nil
+	}
 	return false
 }
 

scalars_test.go

@@ -5,6 +5,50 @@ import (
 	"testing"
 )
 
+type (
+	myInt     int
+	myString  string
+	myBool    bool
+	myFloat32 float32
+)
+
+func TestCoerceString(t *testing.T) {
+	tests := []struct {
+		in   interface{}
+		want interface{}
+	}{
+		{
+			in:   "hello",
+			want: "hello",
+		},
+		{
+			in:   func() interface{} { s := "hello"; return &s }(),
+			want: "hello",
+		},
+		// Typedef
+		{
+			in:   myString("hello"),
+			want: "hello",
+		},
+		// Typedef with pointer
+		{
+			in:   func() interface{} { v := myString("hello"); return &v }(),
+			want: "hello",
+		},
+		// Typedef with nil pointer
+		{
+			in:   (*myString)(nil),
+			want: nil,
+		},
+	}
+
+	for i, tt := range tests {
+		if got, want := coerceString(tt.in), tt.want; got != want {
+			t.Errorf("%d: in=%#v, got=%#v, want=%#v", i, tt.in, got, want)
+		}
+	}
+}
+
 func TestCoerceInt(t *testing.T) {
 	tests := []struct {
 		in   interface{}
@@ -240,11 +284,26 @@ func TestCoerceInt(t *testing.T) {
 			in:   make(map[string]interface{}),
 			want: nil,
 		},
+		// Typedef
+		{
+			in:   myInt(42),
+			want: int(42),
+		},
+		// Typedef with pointer
+		{
+			in:   func() interface{} { v := myInt(42); return &v }(),
+			want: int(42),
+		},
+		// Typedef with nil pointer
+		{
+			in:   (*myInt)(nil),
+			want: nil,
+		},
 	}
 
 	for i, tt := range tests {
 		if got, want := coerceInt(tt.in), tt.want; got != want {
-			t.Errorf("%d: in=%v, got=%v, want=%v", i, tt.in, got, want)
+			t.Errorf("%d: in=%#v, got=%#v, want=%#v", i, tt.in, got, want)
 		}
 	}
 }
@@ -438,11 +497,26 @@ func TestCoerceFloat(t *testing.T) {
 			in:   make(map[string]interface{}),
 			want: nil,
 		},
+		// Typedef
+		{
+			in:   myFloat32(3.14),
+			want: float32(3.14),
+		},
+		// Typedef with pointer
+		{
+			in:   func() interface{} { v := myFloat32(3.14); return &v }(),
+			want: float32(3.14),
+		},
+		// Typedef with nil pointer
+		{
+			in:   (*myFloat32)(nil),
+			want: nil,
+		},
 	}
 
 	for i, tt := range tests {
 		if got, want := coerceFloat(tt.in), tt.want; got != want {
-			t.Errorf("%d: in=%v, got=%v, want=%v", i, tt.in, got, want)
+			t.Errorf("%d: in=%#v, got=%#v, want=%#v", i, tt.in, got, want)
 		}
 	}
 }
@@ -740,11 +814,26 @@ func TestCoerceBool(t *testing.T) {
 			in:   make(map[string]interface{}),
 			want: false,
 		},
+		// Typedef
+		{
+			in:   myBool(true),
+			want: true,
+		},
+		// Typedef with pointer
+		{
+			in:   func() interface{} { v := myBool(true); return &v }(),
+			want: true,
+		},
+		// Typedef with nil pointer
+		{
+			in:   (*myBool)(nil),
+			want: nil,
+		},
 	}
 
 	for i, tt := range tests {
 		if got, want := coerceBool(tt.in), tt.want; got != want {
-			t.Errorf("%d: in=%v, got=%v, want=%v", i, tt.in, got, want)
+			t.Errorf("%d: in=%#v, got=%#v, want=%#v", i, tt.in, got, want)
 		}
 	}
 }