multica-ai/multica · error

create %s copy %s: %w

Error message

create %s copy %s: %w

What it means

The destination file inside the verified task home is created with root.OpenFile using O_EXCL, so creation fails if the entry already exists after the stale-removal step, if permissions deny, or if an intermediate symlink escapes the root. This is the exclusive-create safeguard that prevents overwriting anything unexpectedly.

Source

Thrown at server/internal/daemon/execenv/codex_home.go:1038

		}
	}
	if _, err := root.Lstat(relPath); err == nil {
		if err := root.Remove(relPath); err != nil {
			return fmt.Errorf("remove stale %s copy %s: %w", key, relPath, err)
		}
	} else if !os.IsNotExist(err) {
		return fmt.Errorf("stat %s copy %s: %w", key, relPath, err)
	}

	in, err := os.Open(src)
	if err != nil {
		return fmt.Errorf("open %s %s: %w", key, src, err)
	}
	defer in.Close()

	out, err := root.OpenFile(relPath, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0o644)
	if err != nil {
		return fmt.Errorf("create %s copy %s: %w", key, relPath, err)
	}
	defer out.Close()

	if _, err := io.Copy(out, in); err != nil {
		return fmt.Errorf("copy %s %s to %s: %w", key, src, relPath, err)
	}
	// Close explicitly so a deferred write-back failure cannot be swallowed; the
	// deferred Close then no-ops.
	if err := out.Close(); err != nil {
		return fmt.Errorf("close %s copy %s: %w", key, relPath, err)
	}
	return nil
}

// syncCodexModelsCache seeds models_cache.json once for a fresh task home and
// binds it to the shared provider/catalog configuration. Codex can replace the
// task-local cache after startup, so an unchanged binding preserves whatever
// the task last wrote rather than restoring a potentially stale shared copy.

View on GitHub (pinned to 2c0912b6ec)

Solutions

1. Re-run prepare — the stale-removal step will clear a pre-existing entry
2. Ensure the task home directory is writable by the daemon
3. Remove any escaping symlink on the destination path

if err := materialiseInCodexHome(...); err != nil && strings.Contains(err.Error(), "create "+key+" copy") {
	err = materialiseInCodexHome(...) // stale-removal step clears the entry
}

When it happens

Trigger: relPath was recreated between the Remove and the OpenFile; the containing directory is not writable; an escaping symlink sits in the path.

Common situations: Concurrent process writing the same config path; directory permissions changed by prior task.

Related errors

• stat codex home %s: %w
• read attachment %s: %w
• open codex home %s: %w
• stat opened codex home %s: %w
• codex home %s was replaced while opening it; refusing to wri

AI-assisted analysis of multica-ai/multica@2c0912b6ec (2026-08-15). Data as JSON: /api/errors/b9209ee264a4689c. Report an issue: GitHub.