prow/gerrit/client/client.go
func (c *Client) GetBranchRevision(instance, project, branch string) (string, error) {
	h, ok := c.handlers[instance]
	if !ok {
		return "", fmt.Errorf("not activated gerrit instance: %s", instance)
	}

	res, _, err := h.projectService.GetBranch(project, branch)
	if err != nil {
		return "", err
	}

	return res.Revision, nil
}
func (c *Client) GetBranchRevision(instance, project, branch string) (string, error) {
	h, ok := c.handlers[instance]
	if !ok {
		return "", fmt.Errorf("not activated gerrit instance: %s", instance)
	}

	res, _, err := h.projectService.GetBranch(project, branch)
	if err != nil {
		return "", err
	}

	return res.Revision, nil
}
// GetBranchRevision returns SHA of HEAD of a branch