Update dependencies (#1784)

vendor/github.com/graph-gophers/graphql-go/errors/errors.go

@@ -0,0 +1,59 @@
+package errors
+
+import (
+	"fmt"
+)
+
+type QueryError struct {
+	Err           error                  `json:"-"` // Err holds underlying if available
+	Message       string                 `json:"message"`
+	Locations     []Location             `json:"locations,omitempty"`
+	Path          []interface{}          `json:"path,omitempty"`
+	Rule          string                 `json:"-"`
+	ResolverError error                  `json:"-"`
+	Extensions    map[string]interface{} `json:"extensions,omitempty"`
+}
+
+type Location struct {
+	Line   int `json:"line"`
+	Column int `json:"column"`
+}
+
+func (a Location) Before(b Location) bool {
+	return a.Line < b.Line || (a.Line == b.Line && a.Column < b.Column)
+}
+
+func Errorf(format string, a ...interface{}) *QueryError {
+	// similar to fmt.Errorf, Errorf will wrap the last argument if it is an instance of error
+	var err error
+	if n := len(a); n > 0 {
+		if v, ok := a[n-1].(error); ok {
+			err = v
+		}
+	}
+
+	return &QueryError{
+		Err:     err,
+		Message: fmt.Sprintf(format, a...),
+	}
+}
+
+func (err *QueryError) Error() string {
+	if err == nil {
+		return "<nil>"
+	}
+	str := fmt.Sprintf("graphql: %s", err.Message)
+	for _, loc := range err.Locations {
+		str += fmt.Sprintf(" (line %d, column %d)", loc.Line, loc.Column)
+	}
+	return str
+}
+
+func (err *QueryError) Unwrap() error {
+	if err == nil {
+		return nil
+	}
+	return err.Err
+}
+
+var _ error = &QueryError{}