| 1 | // Package worktree creates durable, Git-backed workspaces for parallel |
| 2 | // Delivery sessions. Attached worktrees live under Reasonix-managed state, |
| 3 | // never inside the source repository, and are never deleted automatically; |
| 4 | // an exact untouched allocation may be rolled back before it is attached. |
| 5 | package worktree |
| 6 | |
| 7 | import ( |
| 8 | "bytes" |
| 9 | "context" |
| 10 | "crypto/rand" |
| 11 | "crypto/sha256" |
| 12 | "encoding/hex" |
| 13 | "errors" |
| 14 | "fmt" |
| 15 | "os" |
| 16 | "os/exec" |
| 17 | "path/filepath" |
| 18 | "strings" |
| 19 | "time" |
| 20 | |
| 21 | "reasonix/internal/gitcmd" |
| 22 | ) |
| 23 | |
| 24 | const ( |
| 25 | gitProbeTimeout = 15 * time.Second |
| 26 | gitWorktreeMutationTimeout = 5 * time.Minute |
| 27 | ) |
| 28 | |
| 29 | // Availability describes whether a project can be isolated with Git worktree. |
| 30 | type Availability struct { |
| 31 | Available bool `json:"available"` |
| 32 | Reason string `json:"reason,omitempty"` |
| 33 | RepoRoot string `json:"repoRoot,omitempty"` |
| 34 | Branch string `json:"branch,omitempty"` |
| 35 | SourceDirty bool `json:"sourceDirty,omitempty"` |
| 36 | } |
| 37 | |
| 38 | // RollbackCreate removes a worktree and its branch only while they still match |
| 39 | // the exact clean result returned by Create. Any user or Git mutation makes the |
| 40 | // rollback fail closed and leaves the workspace available for recovery. |
| 41 | func RollbackCreate(ctx context.Context, result Result) error { |
| 42 | sourceRoot := strings.TrimSpace(result.SourceRoot) |
| 43 | worktreeRoot := strings.TrimSpace(result.WorktreeRoot) |
| 44 | branch := strings.TrimSpace(result.Branch) |
| 45 | head := strings.TrimSpace(result.Head) |
| 46 | if sourceRoot == "" || worktreeRoot == "" || branch == "" || head == "" { |
| 47 | return errors.New("rollback needs the complete created worktree identity") |
| 48 | } |
| 49 | if !strings.HasPrefix(branch, "reasonix/delivery-") { |
| 50 | return fmt.Errorf("refuse to roll back unmanaged branch %q", branch) |
| 51 | } |
| 52 | source, created, err := result.repos(ctx) |
| 53 | if err != nil { |
| 54 | return fmt.Errorf("resolve rollback repositories: %w", err) |
| 55 | } |
| 56 | if _, _, err := runGit(ctx, source, "check-ref-format", "refs/heads/"+branch); err != nil { |
| 57 | return fmt.Errorf("refuse to roll back invalid branch %q", branch) |
| 58 | } |
| 59 | |
| 60 | sourceInfo, err := os.Stat(sourceRoot) |
| 61 | if err != nil { |
| 62 | return fmt.Errorf("inspect rollback source: %w", err) |
| 63 | } |
| 64 | if !sourceInfo.IsDir() { |
| 65 | return errors.New("rollback source is not a directory") |
| 66 | } |
| 67 | worktreeInfo, err := os.Stat(worktreeRoot) |
| 68 | if err != nil { |
| 69 | return fmt.Errorf("inspect rollback worktree: %w", err) |
| 70 | } |
| 71 | if !worktreeInfo.IsDir() { |
| 72 | return errors.New("rollback worktree is not a directory") |
| 73 | } |
| 74 | if os.SameFile(sourceInfo, worktreeInfo) { |
| 75 | return errors.New("refuse to remove the source worktree") |
| 76 | } |
| 77 | reportedInfo, err := os.Stat(created.WorkTree) |
| 78 | if err != nil || !os.SameFile(worktreeInfo, reportedInfo) { |
| 79 | return errors.New("rollback target is not the exact created worktree root") |
| 80 | } |
| 81 | if err := verifySameCommonDir(source, created); err != nil { |
| 82 | return err |
| 83 | } |
| 84 | currentBranch, _, err := runGit(ctx, created, "symbolic-ref", "--quiet", "--short", "HEAD") |
| 85 | if err != nil || strings.TrimSpace(currentBranch) != branch { |
| 86 | return fmt.Errorf("rollback worktree branch changed from %q", branch) |
| 87 | } |
| 88 | currentHead, _, err := runGit(ctx, created, "rev-parse", "--verify", "HEAD") |
| 89 | if err != nil || strings.TrimSpace(currentHead) != head { |
| 90 | return errors.New("rollback worktree HEAD changed after creation") |
| 91 | } |
| 92 | status, _, err := runGit(ctx, created, "status", "--porcelain=v1", "--untracked-files=all", "--ignored") |
| 93 | if err != nil { |
| 94 | return fmt.Errorf("inspect rollback worktree changes: %w", err) |
| 95 | } |
| 96 | if strings.TrimSpace(status) != "" { |
| 97 | return errors.New("rollback worktree contains changes; it was preserved") |
| 98 | } |
| 99 | metadataFile, err := verifyRollbackMetadata(sourceRoot, worktreeRoot, branch, head) |
| 100 | if err != nil { |
| 101 | return err |
| 102 | } |
| 103 | // --force after the clean-tree check above: a bare remove runs status |
| 104 | // inside the linked worktree, whose config.worktree the source-root |
| 105 | // listing never saw. The check already confirmed the tree is clean. |
| 106 | if _, stderr, err := runGit(ctx, source, "worktree", "remove", "--force", worktreeRoot); err != nil { |
| 107 | return fmt.Errorf("remove unused worktree: %w%s", err, stderrSuffix(stderr)) |
| 108 | } |
| 109 | if _, stderr, err := runGit(ctx, source, "update-ref", "-d", "refs/heads/"+branch, head); err != nil { |
| 110 | return fmt.Errorf("remove unused worktree branch %q: %w%s", branch, err, stderrSuffix(stderr)) |
| 111 | } |
| 112 | if err := removeMergeMetadata(metadataFile); err != nil { |
| 113 | return fmt.Errorf("remove unused worktree metadata: %w", err) |
| 114 | } |
| 115 | return nil |
| 116 | } |
| 117 | |
| 118 | // verifySameCommonDir compares the common dirs the two identities were pinned |
| 119 | // with; neither is rediscovered from its checkout. |
| 120 | func verifySameCommonDir(source, worktree gitcmd.Repo) error { |
| 121 | sourceInfo, err := os.Stat(source.CommonDir) |
| 122 | if err != nil { |
| 123 | return fmt.Errorf("resolve rollback source repository: %w", err) |
| 124 | } |
| 125 | worktreeInfo, err := os.Stat(worktree.CommonDir) |
| 126 | if err != nil || !os.SameFile(sourceInfo, worktreeInfo) { |
| 127 | return errors.New("rollback source and worktree do not share a Git repository") |
| 128 | } |
| 129 | return nil |
| 130 | } |
| 131 | |
| 132 | // Result identifies one newly created isolated Delivery workspace. |
| 133 | type Result struct { |
| 134 | WorkspaceRoot string `json:"workspaceRoot"` |
| 135 | WorktreeRoot string `json:"worktreeRoot"` |
| 136 | SourceRoot string `json:"sourceRoot"` |
| 137 | Branch string `json:"branch"` |
| 138 | Head string `json:"head"` |
| 139 | SourceDirty bool `json:"sourceDirty"` |
| 140 | SourceRepo gitcmd.Repo `json:"-"` // the source's identity, at its root |
| 141 | WorktreeRepo gitcmd.Repo `json:"-"` // resolved as the worktree was added |
| 142 | } |
| 143 | |
| 144 | // repos is the pinned source and worktree identities; a Result built without |
| 145 | // them resolves each from its root. |
| 146 | func (r Result) repos(ctx context.Context) (source, worktree gitcmd.Repo, err error) { |
| 147 | source, worktree = r.SourceRepo, r.WorktreeRepo |
| 148 | if !source.Valid() { |
| 149 | if source, err = gitcmd.Open(ctx, r.SourceRoot); err != nil { |
| 150 | return source, worktree, err |
| 151 | } |
| 152 | } |
| 153 | if !worktree.Valid() { |
| 154 | worktree, err = gitcmd.Open(ctx, r.WorktreeRoot) |
| 155 | } |
| 156 | return source.Top(), worktree.Top(), err |
| 157 | } |
| 158 | |
| 159 | type inspection struct { |
| 160 | Availability |
| 161 | repo gitcmd.Repo // pinned at the work tree root |
| 162 | head string |
| 163 | prefix string |
| 164 | } |
| 165 | |
| 166 | // Inspect checks Git and repository prerequisites without changing state. |
| 167 | // repo is the workspace's identity, resolved when it was opened. |
| 168 | func Inspect(ctx context.Context, repo gitcmd.Repo) Availability { |
| 169 | info, err := inspect(ctx, repo) |
| 170 | if err != nil { |
| 171 | return Availability{Available: false, Reason: err.Error()} |
| 172 | } |
| 173 | return info.Availability |
| 174 | } |
| 175 | |
| 176 | // Create makes a new branch and linked worktree at managedRoot, based on the |
| 177 | // source repository's committed HEAD. Uncommitted source changes are reported |
| 178 | // but never copied or modified. When workspaceRoot names a repository |
| 179 | // subdirectory, Result.WorkspaceRoot points at the corresponding subdirectory |
| 180 | // in the new worktree. repo is the workspace's identity, resolved when it opened. |
| 181 | func Create(ctx context.Context, repo gitcmd.Repo, managedRoot string) (Result, error) { |
| 182 | info, err := inspect(ctx, repo) |
| 183 | if err != nil { |
| 184 | return Result{}, err |
| 185 | } |
| 186 | managedRoot = strings.TrimSpace(managedRoot) |
| 187 | if managedRoot == "" { |
| 188 | return Result{}, errors.New("Reasonix worktree storage is unavailable") |
| 189 | } |
| 190 | if err := os.MkdirAll(managedRoot, 0o700); err != nil { |
| 191 | return Result{}, fmt.Errorf("create Reasonix worktree storage: %w", err) |
| 192 | } |
| 193 | |
| 194 | repoSum := sha256.Sum256([]byte(info.repo.CommonDir)) |
| 195 | repoKey := hex.EncodeToString(repoSum[:8]) |
| 196 | repoBase := safePathComponent(filepath.Base(info.RepoRoot)) |
| 197 | if repoBase == "" { |
| 198 | repoBase = "repository" |
| 199 | } |
| 200 | |
| 201 | for range 5 { |
| 202 | id, randomErr := randomID() |
| 203 | if randomErr != nil { |
| 204 | return Result{}, randomErr |
| 205 | } |
| 206 | branch := fmt.Sprintf("reasonix/delivery-%s-%s", time.Now().Format("20060102-150405"), id) |
| 207 | worktreeRoot := filepath.Join(managedRoot, repoKey, id, repoBase) |
| 208 | if _, statErr := os.Stat(worktreeRoot); statErr == nil { |
| 209 | continue |
| 210 | } else if !os.IsNotExist(statErr) { |
| 211 | return Result{}, fmt.Errorf("inspect worktree destination: %w", statErr) |
| 212 | } |
| 213 | if err := os.MkdirAll(filepath.Dir(worktreeRoot), 0o700); err != nil { |
| 214 | return Result{}, fmt.Errorf("create worktree parent: %w", err) |
| 215 | } |
| 216 | |
| 217 | // --no-checkout, then populate through gitcmd inside the new worktree, |
| 218 | // where the reset's driver listing sees an includeIf keyed on that |
| 219 | // worktree's gitdir or new branch (a checkout during add would not). |
| 220 | _, stderr, addErr := runGit(ctx, info.repo, "worktree", "add", "--no-checkout", "-b", branch, worktreeRoot, info.head) |
| 221 | var created gitcmd.Repo |
| 222 | if addErr == nil { |
| 223 | var resetStderr string |
| 224 | var resetErr error |
| 225 | if created, resetStderr, resetErr = populate(ctx, worktreeRoot, info.head); resetErr != nil { |
| 226 | _, _, _ = runGit(ctx, info.repo, "worktree", "remove", "--force", worktreeRoot) |
| 227 | _, _, _ = runGit(ctx, info.repo, "update-ref", "-d", "refs/heads/"+branch, info.head) |
| 228 | return Result{}, fmt.Errorf("populate Git worktree: %w%s", resetErr, stderrSuffix(resetStderr)) |
| 229 | } |
| 230 | } |
| 231 | if addErr != nil { |
| 232 | // A random branch collision is retryable. We deliberately leave any |
| 233 | // non-empty partial directory untouched rather than risk deleting user |
| 234 | // data after Git returned an ambiguous failure. |
| 235 | if strings.Contains(strings.ToLower(stderr), "already exists") { |
| 236 | continue |
| 237 | } |
| 238 | return Result{}, fmt.Errorf("create Git worktree: %w%s", addErr, stderrSuffix(stderr)) |
| 239 | } |
| 240 | |
| 241 | selectedRoot := worktreeRoot |
| 242 | if prefix := filepath.FromSlash(strings.Trim(strings.TrimSpace(info.prefix), "/")); prefix != "" && prefix != "." { |
| 243 | selectedRoot = filepath.Join(worktreeRoot, prefix) |
| 244 | st, statErr := os.Stat(selectedRoot) |
| 245 | if statErr != nil || !st.IsDir() { |
| 246 | return Result{}, fmt.Errorf("created worktree is missing selected project subdirectory %q", prefix) |
| 247 | } |
| 248 | } |
| 249 | result := Result{ |
| 250 | WorkspaceRoot: selectedRoot, |
| 251 | WorktreeRoot: worktreeRoot, |
| 252 | SourceRoot: info.RepoRoot, |
| 253 | Branch: branch, |
| 254 | Head: info.head, |
| 255 | SourceDirty: info.SourceDirty, |
| 256 | SourceRepo: info.repo, |
| 257 | WorktreeRepo: created, |
| 258 | } |
| 259 | if err := writeMergeMetadata(result, info.Branch); err != nil { |
| 260 | rollbackErr := RollbackCreate(ctx, result) |
| 261 | if rollbackErr != nil { |
| 262 | return Result{}, fmt.Errorf("publish merge metadata and roll back allocation: %w", errors.Join(err, fmt.Errorf("exact-clean rollback failed and the worktree was preserved: %w", rollbackErr))) |
| 263 | } |
| 264 | return Result{}, err |
| 265 | } |
| 266 | return result, nil |
| 267 | } |
| 268 | return Result{}, errors.New("could not allocate a unique Delivery worktree") |
| 269 | } |
| 270 | |
| 271 | // IsManagedPath reports whether path belongs to Reasonix's durable worktree |
| 272 | // storage. It is a lexical UI identity check, not an authorization boundary. |
| 273 | func IsManagedPath(path, managedRoot string) bool { |
| 274 | path = strings.TrimSpace(path) |
| 275 | managedRoot = strings.TrimSpace(managedRoot) |
| 276 | if path == "" || managedRoot == "" { |
| 277 | return false |
| 278 | } |
| 279 | absPath, err := filepath.Abs(path) |
| 280 | if err != nil { |
| 281 | return false |
| 282 | } |
| 283 | absManaged, err := filepath.Abs(managedRoot) |
| 284 | if err != nil { |
| 285 | return false |
| 286 | } |
| 287 | rel, err := filepath.Rel(filepath.Clean(absManaged), filepath.Clean(absPath)) |
| 288 | if err != nil || rel == "." || rel == "" { |
| 289 | return false |
| 290 | } |
| 291 | return rel != ".." && !strings.HasPrefix(rel, ".."+string(filepath.Separator)) |
| 292 | } |
| 293 | |
| 294 | func inspect(ctx context.Context, repo gitcmd.Repo) (inspection, error) { |
| 295 | workspaceRoot := strings.TrimSpace(repo.Dir) |
| 296 | if workspaceRoot == "" { |
| 297 | return inspection{}, errors.New("project folder is required") |
| 298 | } |
| 299 | st, err := os.Stat(workspaceRoot) |
| 300 | if err != nil { |
| 301 | return inspection{}, fmt.Errorf("project folder is unavailable: %w", err) |
| 302 | } |
| 303 | if !st.IsDir() { |
| 304 | return inspection{}, errors.New("project path is not a folder") |
| 305 | } |
| 306 | if _, err := exec.LookPath("git"); err != nil { |
| 307 | return inspection{}, errors.New("Git is not installed; Delivery remains safe and will serialize writes in this folder") |
| 308 | } |
| 309 | if !repo.Valid() { |
| 310 | return inspection{}, fmt.Errorf("project folder is not inside a Git repository: %w", gitcmd.ErrNotRepository) |
| 311 | } |
| 312 | top := repo.Top() |
| 313 | head, _, err := runGit(ctx, top, "rev-parse", "--verify", "HEAD") |
| 314 | if err != nil || strings.TrimSpace(head) == "" { |
| 315 | return inspection{}, errors.New("the Git repository needs an initial commit before a worktree can be created") |
| 316 | } |
| 317 | head = strings.TrimSpace(head) |
| 318 | prefix, _, err := runGit(ctx, repo, "rev-parse", "--show-prefix") |
| 319 | if err != nil { |
| 320 | return inspection{}, fmt.Errorf("resolve selected project path inside repository: %w", err) |
| 321 | } |
| 322 | prefix = strings.TrimSpace(prefix) |
| 323 | if prefix != "" { |
| 324 | objectType, _, objectErr := runGit(ctx, top, "cat-file", "-t", head+":"+strings.TrimSuffix(prefix, "/")) |
| 325 | if objectErr != nil || strings.TrimSpace(objectType) != "tree" { |
| 326 | return inspection{}, errors.New("the selected project folder is not present in the committed HEAD; commit it before creating a worktree") |
| 327 | } |
| 328 | } |
| 329 | branch, _, _ := runGit(ctx, top, "symbolic-ref", "--quiet", "--short", "HEAD") |
| 330 | status, _, statusErr := runGit(ctx, top, "status", "--porcelain=v1", "--untracked-files=normal") |
| 331 | if statusErr != nil { |
| 332 | return inspection{}, fmt.Errorf("inspect Git working tree: %w", statusErr) |
| 333 | } |
| 334 | return inspection{ |
| 335 | Availability: Availability{ |
| 336 | Available: true, |
| 337 | RepoRoot: top.WorkTree, |
| 338 | Branch: strings.TrimSpace(branch), |
| 339 | SourceDirty: strings.TrimSpace(status) != "", |
| 340 | }, |
| 341 | repo: top, |
| 342 | head: head, |
| 343 | prefix: prefix, |
| 344 | }, nil |
| 345 | } |
| 346 | |
| 347 | // populate checks head out into a worktree the host just added, under the |
| 348 | // identity that worktree resolves to now, before anything else has run in it. |
| 349 | func populate(ctx context.Context, root, head string) (gitcmd.Repo, string, error) { |
| 350 | repo, err := gitcmd.Open(ctx, root) |
| 351 | if err != nil { |
| 352 | return repo, "", err |
| 353 | } |
| 354 | _, stderr, err := runGit(ctx, repo, "reset", "--hard", head) |
| 355 | return repo, stderr, err |
| 356 | } |
| 357 | |
| 358 | func runGit(parent context.Context, repo gitcmd.Repo, args ...string) (stdout, stderr string, err error) { |
| 359 | return runGitEnvInput(parent, repo, "", nil, args...) |
| 360 | } |
| 361 | |
| 362 | func runGitInput(parent context.Context, repo gitcmd.Repo, input string, args ...string) (stdout, stderr string, err error) { |
| 363 | return runGitEnvInput(parent, repo, input, nil, args...) |
| 364 | } |
| 365 | |
| 366 | func runGitEnv(parent context.Context, repo gitcmd.Repo, env []string, args ...string) (stdout, stderr string, err error) { |
| 367 | return runGitEnvInput(parent, repo, "", env, args...) |
| 368 | } |
| 369 | |
| 370 | // runGitEnvInput runs git against repo's identity, pinned when the repository |
| 371 | // was opened, never one rediscovered from the directory. |
| 372 | func runGitEnvInput(parent context.Context, repo gitcmd.Repo, input string, env []string, args ...string) (stdout, stderr string, err error) { |
| 373 | if parent == nil { |
| 374 | parent = context.Background() |
| 375 | } |
| 376 | ctx, cancel := context.WithTimeout(parent, gitTimeout(args)) |
| 377 | defer cancel() |
| 378 | cmd := repo.Command(ctx, args...) |
| 379 | if len(env) > 0 { |
| 380 | cmd.Env = append(cmd.Env, env...) |
| 381 | } |
| 382 | var outBuf, errBuf bytes.Buffer |
| 383 | if input != "" { |
| 384 | cmd.Stdin = strings.NewReader(input) |
| 385 | } |
| 386 | cmd.Stdout = &outBuf |
| 387 | cmd.Stderr = &errBuf |
| 388 | err = cmd.Run() |
| 389 | if ctx.Err() != nil { |
| 390 | err = ctx.Err() |
| 391 | } |
| 392 | return outBuf.String(), strings.TrimSpace(errBuf.String()), err |
| 393 | } |
| 394 | |
| 395 | func gitTimeout(args []string) time.Duration { |
| 396 | if len(args) >= 2 && args[0] == "worktree" && (args[1] == "add" || args[1] == "move" || args[1] == "remove") { |
| 397 | return gitWorktreeMutationTimeout |
| 398 | } |
| 399 | // The reset after worktree add is where the checkout happens. |
| 400 | if len(args) >= 1 && args[0] == "reset" { |
| 401 | return gitWorktreeMutationTimeout |
| 402 | } |
| 403 | return gitProbeTimeout |
| 404 | } |
| 405 | |
| 406 | func randomID() (string, error) { |
| 407 | var b [5]byte |
| 408 | if _, err := rand.Read(b[:]); err != nil { |
| 409 | return "", fmt.Errorf("generate worktree id: %w", err) |
| 410 | } |
| 411 | return hex.EncodeToString(b[:]), nil |
| 412 | } |
| 413 | |
| 414 | func safePathComponent(name string) string { |
| 415 | name = strings.TrimSpace(name) |
| 416 | name = strings.Map(func(r rune) rune { |
| 417 | switch { |
| 418 | case r < 32: |
| 419 | return '-' |
| 420 | case strings.ContainsRune(`/\\:<>"|?*`, r): |
| 421 | return '-' |
| 422 | default: |
| 423 | return r |
| 424 | } |
| 425 | }, name) |
| 426 | name = strings.Trim(name, ". ") |
| 427 | reserved := strings.ToUpper(strings.SplitN(name, ".", 2)[0]) |
| 428 | if reserved == "CON" || reserved == "PRN" || reserved == "AUX" || reserved == "NUL" || |
| 429 | (len(reserved) == 4 && (strings.HasPrefix(reserved, "COM") || strings.HasPrefix(reserved, "LPT")) && reserved[3] >= '1' && reserved[3] <= '9') { |
| 430 | name = "_" + name |
| 431 | } |
| 432 | return name |
| 433 | } |
| 434 | |
| 435 | func stderrSuffix(stderr string) string { |
| 436 | stderr = strings.TrimSpace(stderr) |
| 437 | if stderr == "" { |
| 438 | return "" |
| 439 | } |
| 440 | const max = 500 |
| 441 | if len(stderr) > max { |
| 442 | stderr = stderr[:max] + "…" |
| 443 | } |
| 444 | return ": " + stderr |
| 445 | } |
| 446 |