| 1 | package worktree |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "encoding/json" |
| 6 | "errors" |
| 7 | "fmt" |
| 8 | "os" |
| 9 | "path/filepath" |
| 10 | "runtime" |
| 11 | "strings" |
| 12 | |
| 13 | "reasonix/internal/fileutil" |
| 14 | "reasonix/internal/gitcmd" |
| 15 | ) |
| 16 | |
| 17 | const ( |
| 18 | mergeMetadataVersion = 1 |
| 19 | mergeMetadataName = "metadata.json" |
| 20 | // mergeIdentityName holds the pinned identities beside metadata.json, whose |
| 21 | // shape older builds decode strictly and so must not change. |
| 22 | mergeIdentityName = "metadata.repo.json" |
| 23 | ) |
| 24 | |
| 25 | type mergeMetadata struct { |
| 26 | Version int `json:"version"` |
| 27 | SourceRoot string `json:"sourceRoot"` |
| 28 | TargetBranch string `json:"targetBranch"` |
| 29 | CreatedHead string `json:"createdHead"` |
| 30 | WorktreeRoot string `json:"worktreeRoot"` |
| 31 | WorktreeBranch string `json:"worktreeBranch"` |
| 32 | // The identities pinned at creation, kept in mergeIdentityName; without |
| 33 | // that file they are resolved from the roots (see source and worktreeAt). |
| 34 | SourceRepo gitcmd.Repo `json:"-"` |
| 35 | WorktreeRepo gitcmd.Repo `json:"-"` |
| 36 | } |
| 37 | |
| 38 | // mergeIdentity is the content of mergeIdentityName. |
| 39 | type mergeIdentity struct { |
| 40 | SourceRepo gitcmd.Repo `json:"sourceRepo"` |
| 41 | WorktreeRepo gitcmd.Repo `json:"worktreeRepo"` |
| 42 | } |
| 43 | |
| 44 | func writeMergeMetadata(result Result, targetBranch string) error { |
| 45 | metadata := mergeMetadata{ |
| 46 | Version: mergeMetadataVersion, |
| 47 | SourceRoot: filepath.Clean(result.SourceRoot), |
| 48 | TargetBranch: strings.TrimSpace(targetBranch), |
| 49 | CreatedHead: strings.TrimSpace(result.Head), |
| 50 | WorktreeRoot: filepath.Clean(result.WorktreeRoot), |
| 51 | WorktreeBranch: strings.TrimSpace(result.Branch), |
| 52 | SourceRepo: result.SourceRepo, |
| 53 | WorktreeRepo: result.WorktreeRepo, |
| 54 | } |
| 55 | body, err := json.MarshalIndent(metadata, "", " ") |
| 56 | if err != nil { |
| 57 | return fmt.Errorf("encode worktree metadata: %w", err) |
| 58 | } |
| 59 | body = append(body, '\n') |
| 60 | if err := fileutil.AtomicCreateFile(metadataPath(result.WorktreeRoot), body, 0o600); err != nil { |
| 61 | return fmt.Errorf("publish worktree metadata: %w", err) |
| 62 | } |
| 63 | identity, err := json.MarshalIndent(mergeIdentity{SourceRepo: result.SourceRepo, WorktreeRepo: result.WorktreeRepo}, "", " ") |
| 64 | if err != nil { |
| 65 | return fmt.Errorf("encode worktree identity: %w", err) |
| 66 | } |
| 67 | if err := fileutil.AtomicCreateFile(identityPath(metadataPath(result.WorktreeRoot)), append(identity, '\n'), 0o600); err != nil { |
| 68 | return fmt.Errorf("publish worktree identity: %w", err) |
| 69 | } |
| 70 | return nil |
| 71 | } |
| 72 | |
| 73 | func identityPath(metadataFile string) string { |
| 74 | return filepath.Join(filepath.Dir(metadataFile), mergeIdentityName) |
| 75 | } |
| 76 | |
| 77 | // removeMergeMetadata removes metadataFile and the identity beside it. |
| 78 | func removeMergeMetadata(metadataFile string) error { |
| 79 | if err := os.Remove(identityPath(metadataFile)); err != nil && !errors.Is(err, os.ErrNotExist) { |
| 80 | return err |
| 81 | } |
| 82 | if err := os.Remove(metadataFile); err != nil && !errors.Is(err, os.ErrNotExist) { |
| 83 | return err |
| 84 | } |
| 85 | return nil |
| 86 | } |
| 87 | |
| 88 | // readMergeIdentity fills the pinned identities from the file beside |
| 89 | // metadataFile; a missing file leaves them unresolved. |
| 90 | func readMergeIdentity(metadataFile string, metadata *mergeMetadata) error { |
| 91 | path := identityPath(metadataFile) |
| 92 | info, err := os.Lstat(path) |
| 93 | if errors.Is(err, os.ErrNotExist) { |
| 94 | return nil |
| 95 | } |
| 96 | if err != nil { |
| 97 | return fmt.Errorf("inspect worktree identity: %w", err) |
| 98 | } |
| 99 | if !info.Mode().IsRegular() || (runtime.GOOS != "windows" && info.Mode().Perm()&0o077 != 0) { |
| 100 | return errors.New("worktree identity is not a private regular file") |
| 101 | } |
| 102 | body, err := os.ReadFile(path) |
| 103 | if err != nil { |
| 104 | return fmt.Errorf("read worktree identity: %w", err) |
| 105 | } |
| 106 | var identity mergeIdentity |
| 107 | decoder := json.NewDecoder(strings.NewReader(string(body))) |
| 108 | decoder.DisallowUnknownFields() |
| 109 | if err := decoder.Decode(&identity); err != nil { |
| 110 | return fmt.Errorf("decode worktree identity: %w", err) |
| 111 | } |
| 112 | metadata.SourceRepo, metadata.WorktreeRepo = identity.SourceRepo, identity.WorktreeRepo |
| 113 | return nil |
| 114 | } |
| 115 | |
| 116 | // source is the source checkout's pinned identity, checked against the |
| 117 | // recorded source root. |
| 118 | func (m mergeMetadata) source(ctx context.Context) (gitcmd.Repo, error) { |
| 119 | repo := m.SourceRepo |
| 120 | if !repo.Valid() { |
| 121 | var err error |
| 122 | if repo, err = gitcmd.Open(ctx, m.SourceRoot); err != nil { |
| 123 | return repo, err |
| 124 | } |
| 125 | } |
| 126 | repo = repo.Top() |
| 127 | if err := repo.Verify(); err != nil { |
| 128 | return repo, fmt.Errorf("source checkout identity changed: %w", err) |
| 129 | } |
| 130 | if err := sameDirectory(repo.WorkTree, m.SourceRoot); err != nil { |
| 131 | return repo, fmt.Errorf("source checkout identity changed: %w", err) |
| 132 | } |
| 133 | return repo, nil |
| 134 | } |
| 135 | |
| 136 | // worktreeAt is the worktree's pinned identity with its checkout at root, |
| 137 | // where a cleanup move may have put it; git keeps its administrative dir. |
| 138 | func (m mergeMetadata) worktreeAt(ctx context.Context, root string) (gitcmd.Repo, error) { |
| 139 | if !m.WorktreeRepo.Valid() { |
| 140 | repo, err := gitcmd.Open(ctx, root) |
| 141 | return repo.Top(), err |
| 142 | } |
| 143 | repo := m.WorktreeRepo |
| 144 | repo.Dir, repo.WorkTree = root, root |
| 145 | return repo, repo.Verify() |
| 146 | } |
| 147 | |
| 148 | func metadataPath(worktreeRoot string) string { |
| 149 | return filepath.Join(filepath.Dir(filepath.Clean(worktreeRoot)), mergeMetadataName) |
| 150 | } |
| 151 | |
| 152 | func readMergeMetadata(worktreeRoot, managedRoot string) (mergeMetadata, string, error) { |
| 153 | root, err := validateManagedWorktreePath(worktreeRoot, managedRoot) |
| 154 | if err != nil { |
| 155 | return mergeMetadata{}, "", err |
| 156 | } |
| 157 | path := metadataPath(root) |
| 158 | info, err := os.Lstat(path) |
| 159 | if errors.Is(err, os.ErrNotExist) { |
| 160 | return mergeMetadata{}, path, errors.New("this worktree predates safe Merge-Back metadata; merge it manually from its source checkout") |
| 161 | } |
| 162 | if err != nil { |
| 163 | return mergeMetadata{}, path, fmt.Errorf("inspect worktree metadata: %w", err) |
| 164 | } |
| 165 | if !info.Mode().IsRegular() { |
| 166 | return mergeMetadata{}, path, errors.New("worktree metadata is not a regular file") |
| 167 | } |
| 168 | if runtime.GOOS != "windows" && info.Mode().Perm()&0o077 != 0 { |
| 169 | return mergeMetadata{}, path, errors.New("worktree metadata permissions are too broad") |
| 170 | } |
| 171 | metadata, err := decodeMergeMetadata(path) |
| 172 | if err != nil { |
| 173 | return mergeMetadata{}, path, err |
| 174 | } |
| 175 | if err := sameDirectory(root, metadata.WorktreeRoot); err != nil { |
| 176 | return mergeMetadata{}, path, fmt.Errorf("worktree metadata root mismatch: %w", err) |
| 177 | } |
| 178 | metadata.WorktreeRoot = root |
| 179 | metadata.SourceRoot = filepath.Clean(metadata.SourceRoot) |
| 180 | metadata.TargetBranch = strings.TrimSpace(metadata.TargetBranch) |
| 181 | metadata.CreatedHead = strings.TrimSpace(metadata.CreatedHead) |
| 182 | metadata.WorktreeBranch = strings.TrimSpace(metadata.WorktreeBranch) |
| 183 | return metadata, path, nil |
| 184 | } |
| 185 | |
| 186 | func readMergeMetadataForCleanup(worktreeRoot, managedRoot string) (mergeMetadata, string, bool, error) { |
| 187 | rootExists := false |
| 188 | if _, err := os.Lstat(worktreeRoot); err == nil { |
| 189 | rootExists = true |
| 190 | } else if !errors.Is(err, os.ErrNotExist) { |
| 191 | return mergeMetadata{}, "", false, fmt.Errorf("inspect cleanup worktree: %w", err) |
| 192 | } |
| 193 | absManaged, err := filepath.Abs(strings.TrimSpace(managedRoot)) |
| 194 | if err != nil { |
| 195 | return mergeMetadata{}, "", false, fmt.Errorf("resolve managed worktree storage: %w", err) |
| 196 | } |
| 197 | realManaged, err := filepath.EvalSymlinks(absManaged) |
| 198 | if err != nil { |
| 199 | return mergeMetadata{}, "", false, fmt.Errorf("resolve managed worktree storage links: %w", err) |
| 200 | } |
| 201 | realRoot, err := resolveMissingCleanupPath(worktreeRoot) |
| 202 | if err != nil { |
| 203 | return mergeMetadata{}, "", false, err |
| 204 | } |
| 205 | rel, err := filepath.Rel(filepath.Clean(realManaged), filepath.Clean(realRoot)) |
| 206 | parts := strings.Split(filepath.Clean(rel), string(filepath.Separator)) |
| 207 | if err != nil || len(parts) != 3 || rel == ".." || strings.HasPrefix(rel, ".."+string(filepath.Separator)) { |
| 208 | return mergeMetadata{}, "", false, errors.New("cleanup worktree does not match the managed allocation layout") |
| 209 | } |
| 210 | allocationDir := filepath.Dir(realRoot) |
| 211 | realAllocation, err := filepath.EvalSymlinks(allocationDir) |
| 212 | if err != nil { |
| 213 | return mergeMetadata{}, "", false, fmt.Errorf("resolve cleanup allocation links: %w", err) |
| 214 | } |
| 215 | realRel, err := filepath.Rel(filepath.Clean(realManaged), filepath.Clean(realAllocation)) |
| 216 | if err != nil || realRel == "." || realRel == ".." || strings.HasPrefix(realRel, ".."+string(filepath.Separator)) { |
| 217 | return mergeMetadata{}, "", false, errors.New("cleanup allocation resolves outside managed storage") |
| 218 | } |
| 219 | path := filepath.Join(allocationDir, mergeMetadataName) |
| 220 | metadata, err := decodeMergeMetadata(path) |
| 221 | if err != nil { |
| 222 | return mergeMetadata{}, path, false, err |
| 223 | } |
| 224 | realMetadataRoot, err := resolveMissingCleanupPath(metadata.WorktreeRoot) |
| 225 | if err != nil { |
| 226 | return mergeMetadata{}, path, false, fmt.Errorf("resolve cleanup metadata root: %w", err) |
| 227 | } |
| 228 | if filepath.Clean(realMetadataRoot) != filepath.Clean(realRoot) { |
| 229 | return mergeMetadata{}, path, false, errors.New("cleanup metadata root mismatch") |
| 230 | } |
| 231 | metadata.WorktreeRoot = filepath.Clean(realRoot) |
| 232 | metadata.SourceRoot = filepath.Clean(metadata.SourceRoot) |
| 233 | metadata.TargetBranch = strings.TrimSpace(metadata.TargetBranch) |
| 234 | metadata.CreatedHead = strings.TrimSpace(metadata.CreatedHead) |
| 235 | metadata.WorktreeBranch = strings.TrimSpace(metadata.WorktreeBranch) |
| 236 | return metadata, path, rootExists, nil |
| 237 | } |
| 238 | |
| 239 | func resolveMissingCleanupPath(path string) (string, error) { |
| 240 | absPath, err := filepath.Abs(strings.TrimSpace(path)) |
| 241 | if err != nil { |
| 242 | return "", fmt.Errorf("resolve cleanup worktree: %w", err) |
| 243 | } |
| 244 | realParent, err := filepath.EvalSymlinks(filepath.Dir(absPath)) |
| 245 | if err != nil { |
| 246 | return "", fmt.Errorf("resolve cleanup allocation links: %w", err) |
| 247 | } |
| 248 | return filepath.Join(realParent, filepath.Base(absPath)), nil |
| 249 | } |
| 250 | |
| 251 | func decodeMergeMetadata(path string) (mergeMetadata, error) { |
| 252 | info, err := os.Lstat(path) |
| 253 | if err != nil { |
| 254 | return mergeMetadata{}, fmt.Errorf("inspect worktree metadata: %w", err) |
| 255 | } |
| 256 | if !info.Mode().IsRegular() { |
| 257 | return mergeMetadata{}, errors.New("worktree metadata is not a regular file") |
| 258 | } |
| 259 | if runtime.GOOS != "windows" && info.Mode().Perm()&0o077 != 0 { |
| 260 | return mergeMetadata{}, errors.New("worktree metadata permissions are too broad") |
| 261 | } |
| 262 | body, err := os.ReadFile(path) |
| 263 | if err != nil { |
| 264 | return mergeMetadata{}, fmt.Errorf("read worktree metadata: %w", err) |
| 265 | } |
| 266 | var metadata mergeMetadata |
| 267 | decoder := json.NewDecoder(strings.NewReader(string(body))) |
| 268 | decoder.DisallowUnknownFields() |
| 269 | if err := decoder.Decode(&metadata); err != nil { |
| 270 | return mergeMetadata{}, fmt.Errorf("decode worktree metadata: %w", err) |
| 271 | } |
| 272 | if metadata.Version != mergeMetadataVersion { |
| 273 | return mergeMetadata{}, fmt.Errorf("unsupported worktree metadata version %d", metadata.Version) |
| 274 | } |
| 275 | if strings.TrimSpace(metadata.SourceRoot) == "" || strings.TrimSpace(metadata.CreatedHead) == "" || |
| 276 | strings.TrimSpace(metadata.WorktreeRoot) == "" || strings.TrimSpace(metadata.WorktreeBranch) == "" { |
| 277 | return mergeMetadata{}, errors.New("worktree metadata is incomplete") |
| 278 | } |
| 279 | if !strings.HasPrefix(metadata.WorktreeBranch, "reasonix/delivery-") { |
| 280 | return mergeMetadata{}, errors.New("worktree metadata names an unmanaged branch") |
| 281 | } |
| 282 | if err := readMergeIdentity(path, &metadata); err != nil { |
| 283 | return mergeMetadata{}, err |
| 284 | } |
| 285 | return metadata, nil |
| 286 | } |
| 287 | |
| 288 | func validateManagedWorktreePath(worktreeRoot, managedRoot string) (string, error) { |
| 289 | worktreeRoot = strings.TrimSpace(worktreeRoot) |
| 290 | managedRoot = strings.TrimSpace(managedRoot) |
| 291 | if worktreeRoot == "" || managedRoot == "" { |
| 292 | return "", errors.New("managed worktree identity is incomplete") |
| 293 | } |
| 294 | absManaged, err := filepath.Abs(managedRoot) |
| 295 | if err != nil { |
| 296 | return "", fmt.Errorf("resolve managed worktree storage: %w", err) |
| 297 | } |
| 298 | absRoot, err := filepath.Abs(worktreeRoot) |
| 299 | if err != nil { |
| 300 | return "", fmt.Errorf("resolve worktree root: %w", err) |
| 301 | } |
| 302 | realManaged, err := filepath.EvalSymlinks(absManaged) |
| 303 | if err != nil { |
| 304 | return "", fmt.Errorf("resolve managed worktree storage links: %w", err) |
| 305 | } |
| 306 | realRoot, err := filepath.EvalSymlinks(absRoot) |
| 307 | if err != nil { |
| 308 | return "", fmt.Errorf("resolve worktree links: %w", err) |
| 309 | } |
| 310 | realRel, err := filepath.Rel(filepath.Clean(realManaged), filepath.Clean(realRoot)) |
| 311 | if err != nil || realRel == "." || realRel == "" || realRel == ".." || strings.HasPrefix(realRel, ".."+string(filepath.Separator)) { |
| 312 | return "", errors.New("worktree resolves outside Reasonix-managed storage") |
| 313 | } |
| 314 | parts := strings.Split(filepath.Clean(realRel), string(filepath.Separator)) |
| 315 | if len(parts) != 3 || parts[0] == "" || parts[1] == "" || parts[2] == "" { |
| 316 | return "", errors.New("worktree does not match the managed allocation layout") |
| 317 | } |
| 318 | return filepath.Clean(realRoot), nil |
| 319 | } |
| 320 | |
| 321 | func sameDirectory(left, right string) error { |
| 322 | leftInfo, err := os.Stat(left) |
| 323 | if err != nil { |
| 324 | return err |
| 325 | } |
| 326 | rightInfo, err := os.Stat(right) |
| 327 | if err != nil { |
| 328 | return err |
| 329 | } |
| 330 | if !leftInfo.IsDir() || !rightInfo.IsDir() || !os.SameFile(leftInfo, rightInfo) { |
| 331 | return errors.New("directories are not identical") |
| 332 | } |
| 333 | return nil |
| 334 | } |
| 335 | |
| 336 | func verifyRollbackMetadata(sourceRoot, worktreeRoot, branch, head string) (string, error) { |
| 337 | path := metadataPath(worktreeRoot) |
| 338 | if _, err := os.Stat(path); errors.Is(err, os.ErrNotExist) { |
| 339 | return path, nil |
| 340 | } else if err != nil { |
| 341 | return path, fmt.Errorf("inspect rollback metadata: %w", err) |
| 342 | } |
| 343 | metadata, err := decodeMergeMetadata(path) |
| 344 | if err != nil || metadata.WorktreeBranch != branch || metadata.CreatedHead != head { |
| 345 | return path, errors.New("rollback worktree metadata changed; the worktree was preserved") |
| 346 | } |
| 347 | if err := sameDirectory(metadata.SourceRoot, sourceRoot); err != nil { |
| 348 | return path, errors.New("rollback source metadata changed; the worktree was preserved") |
| 349 | } |
| 350 | return path, nil |
| 351 | } |
| 352 |