Update vendor (#1265)

vendor/github.com/wiggin77/merror/merror.go

@@ -0,0 +1,87 @@
+package merror
+
+// MError represents zero or more errors that can be
+// accumulated via the `Append` method.
+type MError struct {
+	cap       int
+	errors    []error
+	overflow  int
+	formatter FormatterFunc
+}
+
+// New returns a new instance of `MError` with no limit on the
+// number of errors that can be appended.
+func New() *MError {
+	me := &MError{}
+	me.errors = make([]error, 0, 10)
+	return me
+}
+
+// NewWithCap returns a new instance of `MError` with a maximum
+// capacity of `cap` errors. If exceeded only the overflow counter
+// will be incremented.
+//
+// A `cap` of zero of less means no cap and max size of a slice
+// on the current platform is the upper bound.
+func NewWithCap(cap int) *MError {
+	me := New()
+	me.cap = cap
+	return me
+}
+
+// Append adds an error to the aggregated error list.
+func (me *MError) Append(err error) {
+	if err == nil {
+		return
+	}
+	if me.cap > 0 && len(me.errors) >= me.cap {
+		me.overflow++
+	} else {
+		me.errors = append(me.errors, err)
+	}
+}
+
+// Errors returns an array of the `error` instances that have been
+// appended to this `MError`.
+func (me *MError) Errors() []error {
+	return me.errors
+}
+
+// Len returns the number of errors that have been appended.
+func (me *MError) Len() int {
+	return len(me.errors)
+}
+
+// Overflow returns the number of errors that have been truncated
+// because maximum capacity was exceeded.
+func (me *MError) Overflow() int {
+	return me.overflow
+}
+
+// SetFormatter sets the `FormatterFunc` to be used when `Error` is
+// called. The previous `FormatterFunc` is returned.
+func (me *MError) SetFormatter(f FormatterFunc) (old FormatterFunc) {
+	old = me.formatter
+	me.formatter = f
+	return
+}
+
+// ErrorOrNil returns nil if this `MError` contains no errors,
+// otherwise this `MError` is returned.
+func (me *MError) ErrorOrNil() error {
+	if me == nil || len(me.errors) == 0 {
+		return nil
+	}
+	return me
+}
+
+// Error returns a string representation of this MError.
+// The output format depends on the `Formatter` set for this
+// merror instance, or the global formatter if none set.
+func (me *MError) Error() string {
+	f := me.formatter
+	if f == nil {
+		f = GlobalFormatter
+	}
+	return f(me)
+}