func mkCommit(r *git.Repository, refname string, msg string, tree *git.Tree, parent *git.Commit, extraParents ...*git.Commit) (*git.Commit, error) {
var parents []*git.Commit
if parent != nil {
parents = append(parents, parent)
}
if len(extraParents) > 0 {
parents = append(parents, extraParents...)
}
id, err := r.CreateCommit(
refname,
&git.Signature{"libpack", "libpack", time.Now()}, // author
&git.Signature{"libpack", "libpack", time.Now()}, // committer
msg,
tree, // git tree to commit
parents...,
)
if err != nil {
return nil, err
}
return lookupCommit(r, id)
}
