prow/plugins/dco/dco.go
func checkCommitMessages(gc gitHubClient, l *logrus.Entry, org, repo string, number int) ([]github.GitCommit, error) {
	allCommits, err := gc.ListPRCommits(org, repo, number)
	if err != nil {
		return nil, fmt.Errorf("error listing commits for pull request: %v", err)
	}
	l.Debugf("Found %d commits in PR", len(allCommits))

	var commitsMissingDCO []github.GitCommit
	for _, commit := range allCommits {
		if !testRe.MatchString(commit.Commit.Message) {
			c := commit.Commit
			c.SHA = commit.SHA
			commitsMissingDCO = append(commitsMissingDCO, c)
		}
	}

	l.Debugf("All commits in PR have DCO signoff: %t", len(commitsMissingDCO) == 0)
	return commitsMissingDCO, nil
}
func checkCommitMessages(gc gitHubClient, l *logrus.Entry, org, repo string, number int) ([]github.GitCommit, error) {
	allCommits, err := gc.ListPRCommits(org, repo, number)
	if err != nil {
		return nil, fmt.Errorf("error listing commits for pull request: %v", err)
	}
	l.Debugf("Found %d commits in PR", len(allCommits))

	var commitsMissingDCO []github.GitCommit
	for _, commit := range allCommits {
		if !testRe.MatchString(commit.Commit.Message) {
			c := commit.Commit
			c.SHA = commit.SHA
			commitsMissingDCO = append(commitsMissingDCO, c)
		}
	}

	l.Debugf("All commits in PR have DCO signoff: %t", len(commitsMissingDCO) == 0)
	return commitsMissingDCO, nil
}
// checkCommitMessages will perform the actual DCO check by retrieving all
// commits contained within the PR with the given number.
// *All* commits in the pull request *must* match the 'testRe' in order to pass.