diff options
Diffstat (limited to 'cmd/gitaly-git2go/merge.go')
| -rw-r--r-- | cmd/gitaly-git2go/merge.go | 251 |
1 files changed, 251 insertions, 0 deletions
diff --git a/cmd/gitaly-git2go/merge.go b/cmd/gitaly-git2go/merge.go new file mode 100644 index 000000000..4ab3ef9fd --- /dev/null +++ b/cmd/gitaly-git2go/merge.go @@ -0,0 +1,251 @@ +//go:build static && system_libgit2 + +package main + +import ( + "context" + "encoding/gob" + "errors" + "flag" + "fmt" + "time" + + git "github.com/libgit2/git2go/v33" + "gitlab.com/gitlab-org/gitaly/v15/cmd/gitaly-git2go/git2goutil" + "gitlab.com/gitlab-org/gitaly/v15/internal/git2go" +) + +type mergeSubcommand struct{} + +func (cmd *mergeSubcommand) Flags() *flag.FlagSet { + flags := flag.NewFlagSet("merge", flag.ExitOnError) + return flags +} + +func (cmd *mergeSubcommand) Run(_ context.Context, decoder *gob.Decoder, encoder *gob.Encoder) error { + var request git2go.MergeCommand + if err := decoder.Decode(&request); err != nil { + return err + } + + if request.AuthorDate.IsZero() { + request.AuthorDate = time.Now() + } + + commitID, err := merge(request) + + return encoder.Encode(git2go.Result{ + CommitID: commitID, + Err: git2go.SerializableError(err), + }) +} + +func merge(request git2go.MergeCommand) (string, error) { + repo, err := git2goutil.OpenRepository(request.Repository) + if err != nil { + return "", fmt.Errorf("could not open repository: %w", err) + } + defer repo.Free() + + ours, err := lookupCommit(repo, request.Ours) + if err != nil { + return "", fmt.Errorf("ours commit lookup: %w", err) + } + + theirs, err := lookupCommit(repo, request.Theirs) + if err != nil { + return "", fmt.Errorf("theirs commit lookup: %w", err) + } + + mergeOpts, err := git.DefaultMergeOptions() + if err != nil { + return "", fmt.Errorf("could not create merge options: %w", err) + } + mergeOpts.RecursionLimit = git2go.MergeRecursionLimit + + index, err := repo.MergeCommits(ours, theirs, &mergeOpts) + if err != nil { + return "", fmt.Errorf("could not merge commits: %w", err) + } + defer index.Free() + + if index.HasConflicts() { + if !request.AllowConflicts { + conflictingFiles, err := getConflictingFiles(index) + if err != nil { + return "", fmt.Errorf("getting conflicting files: %w", err) + } + + return "", git2go.ConflictingFilesError{ + ConflictingFiles: conflictingFiles, + } + } + + if err := resolveConflicts(repo, index); err != nil { + return "", fmt.Errorf("could not resolve conflicts: %w", err) + } + } + + tree, err := index.WriteTreeTo(repo) + if err != nil { + return "", fmt.Errorf("could not write tree: %w", err) + } + + author := git.Signature(git2go.NewSignature(request.AuthorName, request.AuthorMail, request.AuthorDate)) + committer := author + if request.CommitterMail != "" { + committer = git.Signature(git2go.NewSignature(request.CommitterName, request.CommitterMail, request.CommitterDate)) + } + + var parents []*git.Oid + if request.Squash { + parents = []*git.Oid{ours.Id()} + } else { + parents = []*git.Oid{ours.Id(), theirs.Id()} + } + commit, err := repo.CreateCommitFromIds("", &author, &committer, request.Message, tree, parents...) + if err != nil { + return "", fmt.Errorf("could not create merge commit: %w", err) + } + + return commit.String(), nil +} + +func resolveConflicts(repo *git.Repository, index *git.Index) error { + // We need to get all conflicts up front as resolving conflicts as we + // iterate breaks the iterator. + indexConflicts, err := getConflicts(index) + if err != nil { + return err + } + + for _, conflict := range indexConflicts { + if isConflictMergeable(conflict) { + merge, err := Merge(repo, conflict) + if err != nil { + return err + } + + mergedBlob, err := repo.CreateBlobFromBuffer(merge.Contents) + if err != nil { + return err + } + + mergedIndexEntry := git.IndexEntry{ + Path: merge.Path, + Mode: git.Filemode(merge.Mode), + Id: mergedBlob, + } + + if err := index.Add(&mergedIndexEntry); err != nil { + return err + } + + if err := index.RemoveConflict(merge.Path); err != nil { + return err + } + } else { + if conflict.Their != nil { + // If a conflict has `Their` present, we add it back to the index + // as we want those changes to be part of the merge. + if err := index.Add(conflict.Their); err != nil { + return err + } + + if err := index.RemoveConflict(conflict.Their.Path); err != nil { + return err + } + } else if conflict.Our != nil { + // If a conflict has `Our` present, remove its conflict as we + // don't want to include those changes. + if err := index.RemoveConflict(conflict.Our.Path); err != nil { + return err + } + } else { + // If conflict has no `Their` and `Our`, remove the conflict to + // mark it as resolved. + if err := index.RemoveConflict(conflict.Ancestor.Path); err != nil { + return err + } + } + } + } + + if index.HasConflicts() { + conflictingFiles, err := getConflictingFiles(index) + if err != nil { + return fmt.Errorf("getting conflicting files: %w", err) + } + + return git2go.ConflictingFilesError{ + ConflictingFiles: conflictingFiles, + } + } + + return nil +} + +func getConflictingFiles(index *git.Index) ([]string, error) { + conflicts, err := getConflicts(index) + if err != nil { + return nil, fmt.Errorf("getting conflicts: %w", err) + } + + conflictingFiles := make([]string, 0, len(conflicts)) + for _, conflict := range conflicts { + switch { + case conflict.Our != nil: + conflictingFiles = append(conflictingFiles, conflict.Our.Path) + case conflict.Ancestor != nil: + conflictingFiles = append(conflictingFiles, conflict.Ancestor.Path) + case conflict.Their != nil: + conflictingFiles = append(conflictingFiles, conflict.Their.Path) + default: + return nil, errors.New("invalid conflict") + } + } + + return conflictingFiles, nil +} + +func isConflictMergeable(conflict git.IndexConflict) bool { + conflictIndexEntriesCount := 0 + + if conflict.Their != nil { + conflictIndexEntriesCount++ + } + + if conflict.Our != nil { + conflictIndexEntriesCount++ + } + + if conflict.Ancestor != nil { + conflictIndexEntriesCount++ + } + + return conflictIndexEntriesCount >= 2 +} + +func getConflicts(index *git.Index) ([]git.IndexConflict, error) { + var conflicts []git.IndexConflict + + iterator, err := index.ConflictIterator() + if err != nil { + return nil, err + } + defer iterator.Free() + + for { + conflict, err := iterator.Next() + if err != nil { + if git.IsErrorCode(err, git.ErrorCodeIterOver) { + break + } + return nil, err + } + + conflicts = append(conflicts, conflict) + } + + return conflicts, nil +} |