fix: change cwd to load gqlgen config correctly (#103)

Code copied from 99designs/gqlgen#1511

entgql/extension.go

@@ -17,6 +17,7 @@ package entgql
 import (
 	"fmt"
 	"io/ioutil"
+	"os"
 	"path/filepath"
 	"strings"
 
@@ -31,7 +32,6 @@ import (
 	"github.com/graphql-go/graphql/language/printer"
 	"github.com/graphql-go/graphql/language/source"
 	"github.com/graphql-go/graphql/language/visitor"
-	gqlparserast "github.com/vektah/gqlparser/v2/ast"
 )
 
 type (
@@ -84,18 +84,28 @@ func WithSchemaPath(path string) ExtensionOption {
 // Note that, enabling this option is recommended as it improves the
 // GraphQL integration,
 func WithConfigPath(path string) ExtensionOption {
-	return func(ex *Extension) error {
-		cfg, err := config.LoadConfig(path)
+	return func(ex *Extension) (err error) {
+		cwd, err := os.Getwd()
+		if err != nil {
+			return fmt.Errorf("unable to get working directory: %w", err)
+		}
+		if err := os.Chdir(filepath.Dir(path)); err != nil {
+			return fmt.Errorf("unable to enter config dir: %w", err)
+		}
+		defer func() {
+			if cerr := os.Chdir(cwd); cerr != nil {
+				err = fmt.Errorf("unable to restore working directory: %w", cerr)
+			}
+		}()
+		cfg, err := config.LoadConfig(filepath.Base(path))
 		if err != nil {
 			return err
 		}
-
 		if cfg.Schema == nil {
 			if err := cfg.LoadSchema(); err != nil {
 				return err
 			}
 		}
-
 		ex.cfg = cfg
 		return nil
 	}
@@ -271,11 +281,8 @@ func (e *Extension) hasMapping(f *gen.Field) (string, bool) {
 // isInput reports if the given type is an input object.
 func (e *Extension) isInput(name string) bool {
 	if t, ok := e.cfg.Schema.Types[name]; ok && t != nil {
-		return t.Kind == gqlparserast.Enum ||
-			t.Kind == gqlparserast.Scalar ||
-			t.Kind == gqlparserast.InputObject
+		return t.IsInputType()
 	}
-
 	return false
 }