prow/config/jobs.go
func (c *JobConfig) AllPresubmits(repos []string) []Presubmit {
	var res []Presubmit

	for repo, v := range c.Presubmits {
		if len(repos) == 0 {
			res = append(res, v...)
		} else {
			for _, r := range repos {
				if r == repo {
					res = append(res, v...)
					break
				}
			}
		}
	}

	return res
}
func (c *JobConfig) AllPresubmits(repos []string) []Presubmit {
	var res []Presubmit

	for repo, v := range c.Presubmits {
		if len(repos) == 0 {
			res = append(res, v...)
		} else {
			for _, r := range repos {
				if r == repo {
					res = append(res, v...)
					break
				}
			}
		}
	}

	return res
}
// AllPresubmits returns all prow presubmit jobs in repos.
// if repos is empty, return all presubmits.