func resetIndexFromCommit(repo *libgit.Repository, commitId string) error {
// If the index doesn't exist, idx is a new index, so ignore
// the path error that ReadIndex is returning
idx, _ := ReadIndex(repo)
com, err := repo.GetCommit(commitId)
if err != nil {
fmt.Printf("%s\n", err)
return err
}
treeId := com.TreeId()
tree := libgit.NewTree(repo, treeId)
if tree == nil {
panic("Error retriving tree for commit")
}
idx.ResetIndex(repo, tree)
writeIndex(repo, idx, "index")
return nil
}
func Merge(repo *libgit.Repository, args []string) {
if len(args) != 1 {
fmt.Fprintf(os.Stderr, "Usage: go-git merge branchname\n")
return
}
commit, err := repo.GetCommitOfBranch(args[0])
if err != nil {
fmt.Fprintf(os.Stderr, "Invalid branch: %s\n", args[0])
return
}
head, err := getHeadId(repo)
if err != nil {
panic(err)
}
// The current branch is an ancestor of HEAD. This
// is a fast-forward.
if headCom, err := repo.GetCommit(head); err == nil {
if isAncestor(headCom, fmt.Sprintf("%s", commit.Id)) {
fmt.Fprintf(os.Stderr, "Already up-to-date.\n")
return
}
}
// Head is an ancestor of the current branch.
if isAncestor(commit, head) {
hb := getHeadBranch(repo)
newId := fmt.Sprintf("%s", commit.Id)
ioutil.WriteFile(".git/refs/heads/"+hb, []byte(newId), 0644)
resetIndexFromCommit(repo, newId)
fmt.Printf("Hooray! A Fast forward on %s! New should should be %s\n", hb, commit.Id)
return
}
panic("Only fast forward commits are currently supported.")
}