prow/clonerefs/options.go
func (r *gitRefs) Set(value string) error {
	gitRef, err := ParseRefs(value)
	if err != nil {
		return err
	}
	r.gitRefs = append(r.gitRefs, *gitRef)
	return nil
}
func (r *gitRefs) Set(value string) error {
	gitRef, err := ParseRefs(value)
	if err != nil {
		return err
	}
	r.gitRefs = append(r.gitRefs, *gitRef)
	return nil
}
// Set parses out a prowapi.Refs from the user string.
// The following example shows all possible fields:
//   org,repo=base-ref:base-sha[,pull-number:pull-sha]...
// For the base ref and every pull number, the SHAs
// are optional and any number of them may be set or
// unset.