| 1 | package worktree |
| 2 | |
| 3 | import ( |
| 4 | "encoding/json" |
| 5 | "errors" |
| 6 | "fmt" |
| 7 | "os" |
| 8 | "path/filepath" |
| 9 | "runtime" |
| 10 | "strings" |
| 11 | |
| 12 | "reasonix/internal/fileutil" |
| 13 | ) |
| 14 | |
| 15 | const ( |
| 16 | mergeMetadataVersion = 1 |
| 17 | mergeMetadataName = "metadata.json" |
| 18 | ) |
| 19 | |
| 20 | type mergeMetadata struct { |
| 21 | Version int `json:"version"` |
| 22 | SourceRoot string `json:"sourceRoot"` |
| 23 | TargetBranch string `json:"targetBranch"` |
| 24 | CreatedHead string `json:"createdHead"` |
| 25 | WorktreeRoot string `json:"worktreeRoot"` |
| 26 | WorktreeBranch string `json:"worktreeBranch"` |
| 27 | } |
| 28 | |
| 29 | func writeMergeMetadata(result Result, targetBranch string) error { |
| 30 | metadata := mergeMetadata{ |
| 31 | Version: mergeMetadataVersion, |
| 32 | SourceRoot: filepath.Clean(result.SourceRoot), |
| 33 | TargetBranch: strings.TrimSpace(targetBranch), |
| 34 | CreatedHead: strings.TrimSpace(result.Head), |
| 35 | WorktreeRoot: filepath.Clean(result.WorktreeRoot), |
| 36 | WorktreeBranch: strings.TrimSpace(result.Branch), |
| 37 | } |
| 38 | body, err := json.MarshalIndent(metadata, "", " ") |
| 39 | if err != nil { |
| 40 | return fmt.Errorf("encode worktree metadata: %w", err) |
| 41 | } |
| 42 | body = append(body, '\n') |
| 43 | if err := fileutil.AtomicCreateFile(metadataPath(result.WorktreeRoot), body, 0o600); err != nil { |
| 44 | return fmt.Errorf("publish worktree metadata: %w", err) |
| 45 | } |
| 46 | return nil |
| 47 | } |
| 48 | |
| 49 | func metadataPath(worktreeRoot string) string { |
| 50 | return filepath.Join(filepath.Dir(filepath.Clean(worktreeRoot)), mergeMetadataName) |
| 51 | } |
| 52 | |
| 53 | func readMergeMetadata(worktreeRoot, managedRoot string) (mergeMetadata, string, error) { |
| 54 | root, err := validateManagedWorktreePath(worktreeRoot, managedRoot) |
| 55 | if err != nil { |
| 56 | return mergeMetadata{}, "", err |
| 57 | } |
| 58 | path := metadataPath(root) |
| 59 | info, err := os.Lstat(path) |
| 60 | if errors.Is(err, os.ErrNotExist) { |
| 61 | return mergeMetadata{}, path, errors.New("this worktree predates safe Merge-Back metadata; merge it manually from its source checkout") |
| 62 | } |
| 63 | if err != nil { |
| 64 | return mergeMetadata{}, path, fmt.Errorf("inspect worktree metadata: %w", err) |
| 65 | } |
| 66 | if !info.Mode().IsRegular() { |
| 67 | return mergeMetadata{}, path, errors.New("worktree metadata is not a regular file") |
| 68 | } |
| 69 | if runtime.GOOS != "windows" && info.Mode().Perm()&0o077 != 0 { |
| 70 | return mergeMetadata{}, path, errors.New("worktree metadata permissions are too broad") |
| 71 | } |
| 72 | metadata, err := decodeMergeMetadata(path) |
| 73 | if err != nil { |
| 74 | return mergeMetadata{}, path, err |
| 75 | } |
| 76 | if err := sameDirectory(root, metadata.WorktreeRoot); err != nil { |
| 77 | return mergeMetadata{}, path, fmt.Errorf("worktree metadata root mismatch: %w", err) |
| 78 | } |
| 79 | metadata.WorktreeRoot = root |
| 80 | metadata.SourceRoot = filepath.Clean(metadata.SourceRoot) |
| 81 | metadata.TargetBranch = strings.TrimSpace(metadata.TargetBranch) |
| 82 | metadata.CreatedHead = strings.TrimSpace(metadata.CreatedHead) |
| 83 | metadata.WorktreeBranch = strings.TrimSpace(metadata.WorktreeBranch) |
| 84 | return metadata, path, nil |
| 85 | } |
| 86 | |
| 87 | func readMergeMetadataForCleanup(worktreeRoot, managedRoot string) (mergeMetadata, string, bool, error) { |
| 88 | rootExists := false |
| 89 | if _, err := os.Lstat(worktreeRoot); err == nil { |
| 90 | rootExists = true |
| 91 | } else if !errors.Is(err, os.ErrNotExist) { |
| 92 | return mergeMetadata{}, "", false, fmt.Errorf("inspect cleanup worktree: %w", err) |
| 93 | } |
| 94 | absManaged, err := filepath.Abs(strings.TrimSpace(managedRoot)) |
| 95 | if err != nil { |
| 96 | return mergeMetadata{}, "", false, fmt.Errorf("resolve managed worktree storage: %w", err) |
| 97 | } |
| 98 | realManaged, err := filepath.EvalSymlinks(absManaged) |
| 99 | if err != nil { |
| 100 | return mergeMetadata{}, "", false, fmt.Errorf("resolve managed worktree storage links: %w", err) |
| 101 | } |
| 102 | realRoot, err := resolveMissingCleanupPath(worktreeRoot) |
| 103 | if err != nil { |
| 104 | return mergeMetadata{}, "", false, err |
| 105 | } |
| 106 | rel, err := filepath.Rel(filepath.Clean(realManaged), filepath.Clean(realRoot)) |
| 107 | parts := strings.Split(filepath.Clean(rel), string(filepath.Separator)) |
| 108 | if err != nil || len(parts) != 3 || rel == ".." || strings.HasPrefix(rel, ".."+string(filepath.Separator)) { |
| 109 | return mergeMetadata{}, "", false, errors.New("cleanup worktree does not match the managed allocation layout") |
| 110 | } |
| 111 | allocationDir := filepath.Dir(realRoot) |
| 112 | realAllocation, err := filepath.EvalSymlinks(allocationDir) |
| 113 | if err != nil { |
| 114 | return mergeMetadata{}, "", false, fmt.Errorf("resolve cleanup allocation links: %w", err) |
| 115 | } |
| 116 | realRel, err := filepath.Rel(filepath.Clean(realManaged), filepath.Clean(realAllocation)) |
| 117 | if err != nil || realRel == "." || realRel == ".." || strings.HasPrefix(realRel, ".."+string(filepath.Separator)) { |
| 118 | return mergeMetadata{}, "", false, errors.New("cleanup allocation resolves outside managed storage") |
| 119 | } |
| 120 | path := filepath.Join(allocationDir, mergeMetadataName) |
| 121 | metadata, err := decodeMergeMetadata(path) |
| 122 | if err != nil { |
| 123 | return mergeMetadata{}, path, false, err |
| 124 | } |
| 125 | realMetadataRoot, err := resolveMissingCleanupPath(metadata.WorktreeRoot) |
| 126 | if err != nil { |
| 127 | return mergeMetadata{}, path, false, fmt.Errorf("resolve cleanup metadata root: %w", err) |
| 128 | } |
| 129 | if filepath.Clean(realMetadataRoot) != filepath.Clean(realRoot) { |
| 130 | return mergeMetadata{}, path, false, errors.New("cleanup metadata root mismatch") |
| 131 | } |
| 132 | metadata.WorktreeRoot = filepath.Clean(realRoot) |
| 133 | metadata.SourceRoot = filepath.Clean(metadata.SourceRoot) |
| 134 | metadata.TargetBranch = strings.TrimSpace(metadata.TargetBranch) |
| 135 | metadata.CreatedHead = strings.TrimSpace(metadata.CreatedHead) |
| 136 | metadata.WorktreeBranch = strings.TrimSpace(metadata.WorktreeBranch) |
| 137 | return metadata, path, rootExists, nil |
| 138 | } |
| 139 | |
| 140 | func resolveMissingCleanupPath(path string) (string, error) { |
| 141 | absPath, err := filepath.Abs(strings.TrimSpace(path)) |
| 142 | if err != nil { |
| 143 | return "", fmt.Errorf("resolve cleanup worktree: %w", err) |
| 144 | } |
| 145 | realParent, err := filepath.EvalSymlinks(filepath.Dir(absPath)) |
| 146 | if err != nil { |
| 147 | return "", fmt.Errorf("resolve cleanup allocation links: %w", err) |
| 148 | } |
| 149 | return filepath.Join(realParent, filepath.Base(absPath)), nil |
| 150 | } |
| 151 | |
| 152 | func decodeMergeMetadata(path string) (mergeMetadata, error) { |
| 153 | info, err := os.Lstat(path) |
| 154 | if err != nil { |
| 155 | return mergeMetadata{}, fmt.Errorf("inspect worktree metadata: %w", err) |
| 156 | } |
| 157 | if !info.Mode().IsRegular() { |
| 158 | return mergeMetadata{}, errors.New("worktree metadata is not a regular file") |
| 159 | } |
| 160 | if runtime.GOOS != "windows" && info.Mode().Perm()&0o077 != 0 { |
| 161 | return mergeMetadata{}, errors.New("worktree metadata permissions are too broad") |
| 162 | } |
| 163 | body, err := os.ReadFile(path) |
| 164 | if err != nil { |
| 165 | return mergeMetadata{}, fmt.Errorf("read worktree metadata: %w", err) |
| 166 | } |
| 167 | var metadata mergeMetadata |
| 168 | decoder := json.NewDecoder(strings.NewReader(string(body))) |
| 169 | decoder.DisallowUnknownFields() |
| 170 | if err := decoder.Decode(&metadata); err != nil { |
| 171 | return mergeMetadata{}, fmt.Errorf("decode worktree metadata: %w", err) |
| 172 | } |
| 173 | if metadata.Version != mergeMetadataVersion { |
| 174 | return mergeMetadata{}, fmt.Errorf("unsupported worktree metadata version %d", metadata.Version) |
| 175 | } |
| 176 | if strings.TrimSpace(metadata.SourceRoot) == "" || strings.TrimSpace(metadata.CreatedHead) == "" || |
| 177 | strings.TrimSpace(metadata.WorktreeRoot) == "" || strings.TrimSpace(metadata.WorktreeBranch) == "" { |
| 178 | return mergeMetadata{}, errors.New("worktree metadata is incomplete") |
| 179 | } |
| 180 | if !strings.HasPrefix(metadata.WorktreeBranch, "reasonix/delivery-") { |
| 181 | return mergeMetadata{}, errors.New("worktree metadata names an unmanaged branch") |
| 182 | } |
| 183 | return metadata, nil |
| 184 | } |
| 185 | |
| 186 | func validateManagedWorktreePath(worktreeRoot, managedRoot string) (string, error) { |
| 187 | worktreeRoot = strings.TrimSpace(worktreeRoot) |
| 188 | managedRoot = strings.TrimSpace(managedRoot) |
| 189 | if worktreeRoot == "" || managedRoot == "" { |
| 190 | return "", errors.New("managed worktree identity is incomplete") |
| 191 | } |
| 192 | absManaged, err := filepath.Abs(managedRoot) |
| 193 | if err != nil { |
| 194 | return "", fmt.Errorf("resolve managed worktree storage: %w", err) |
| 195 | } |
| 196 | absRoot, err := filepath.Abs(worktreeRoot) |
| 197 | if err != nil { |
| 198 | return "", fmt.Errorf("resolve worktree root: %w", err) |
| 199 | } |
| 200 | realManaged, err := filepath.EvalSymlinks(absManaged) |
| 201 | if err != nil { |
| 202 | return "", fmt.Errorf("resolve managed worktree storage links: %w", err) |
| 203 | } |
| 204 | realRoot, err := filepath.EvalSymlinks(absRoot) |
| 205 | if err != nil { |
| 206 | return "", fmt.Errorf("resolve worktree links: %w", err) |
| 207 | } |
| 208 | realRel, err := filepath.Rel(filepath.Clean(realManaged), filepath.Clean(realRoot)) |
| 209 | if err != nil || realRel == "." || realRel == "" || realRel == ".." || strings.HasPrefix(realRel, ".."+string(filepath.Separator)) { |
| 210 | return "", errors.New("worktree resolves outside Reasonix-managed storage") |
| 211 | } |
| 212 | parts := strings.Split(filepath.Clean(realRel), string(filepath.Separator)) |
| 213 | if len(parts) != 3 || parts[0] == "" || parts[1] == "" || parts[2] == "" { |
| 214 | return "", errors.New("worktree does not match the managed allocation layout") |
| 215 | } |
| 216 | return filepath.Clean(realRoot), nil |
| 217 | } |
| 218 | |
| 219 | func sameDirectory(left, right string) error { |
| 220 | leftInfo, err := os.Stat(left) |
| 221 | if err != nil { |
| 222 | return err |
| 223 | } |
| 224 | rightInfo, err := os.Stat(right) |
| 225 | if err != nil { |
| 226 | return err |
| 227 | } |
| 228 | if !leftInfo.IsDir() || !rightInfo.IsDir() || !os.SameFile(leftInfo, rightInfo) { |
| 229 | return errors.New("directories are not identical") |
| 230 | } |
| 231 | return nil |
| 232 | } |
| 233 | |
| 234 | func verifyRollbackMetadata(sourceRoot, worktreeRoot, branch, head string) (string, error) { |
| 235 | path := metadataPath(worktreeRoot) |
| 236 | if _, err := os.Stat(path); errors.Is(err, os.ErrNotExist) { |
| 237 | return path, nil |
| 238 | } else if err != nil { |
| 239 | return path, fmt.Errorf("inspect rollback metadata: %w", err) |
| 240 | } |
| 241 | metadata, err := decodeMergeMetadata(path) |
| 242 | if err != nil || metadata.WorktreeBranch != branch || metadata.CreatedHead != head { |
| 243 | return path, errors.New("rollback worktree metadata changed; the worktree was preserved") |
| 244 | } |
| 245 | if err := sameDirectory(metadata.SourceRoot, sourceRoot); err != nil { |
| 246 | return path, errors.New("rollback source metadata changed; the worktree was preserved") |
| 247 | } |
| 248 | return path, nil |
| 249 | } |
| 250 |