brew-cask: generic artifact backup changed directories

Error message

brew-cask: generic artifact backup changed directories

What it means

When mise backs up or restores a generic cask artifact via rename, it requires that both source and target live in the same directory (rename cannot cross filesystems/directories). If from.parent() differs from to.parent(), the backend refuses rather than silently falling back to an unsafe copy. This keeps backup/restore of trusted targets inside the validated parent directory.

Solutions

Reinstall the cask so artifact and backup paths are recomputed consistently under the same parent directory.
Ensure the computed backup/restore path is in the same directory as the artifact (same parent) before triggering upgrade/rollback.
Clear stale artifact records from a previous prefix layout and reinstall.
Report the internal inconsistency if it persists with default configuration — it indicates a backend path-computation bug.

Example fix

// before
let backup = prefix.join("backups").join(name);   // different parent
// after
let backup = artifact.parent().unwrap().join(format!("{}.bak", name));  // same parent

Defensive patterns

Strategy: try-catch

Validate before calling

if backup.parent() != artifact.parent() {
    eprintln!("backup path must share the artifact's parent directory");
    std::process::exit(1);
}

Type guard

fn same_parent(a: &std::path::Path, b: &std::path::Path) -> bool {
    a.parent() == b.parent()
}

Prevention

Compute backup paths from the artifact's own parent, never a separate backups dir.
Reinstall casks after prefix relocations so paths stay consistent.
Do not hand-edit artifact records.
Report persistent mismatches as a backend bug with default config.

When it happens

Trigger: rename_trusted_generic_target is called with 'from' and 'to' paths whose parent directories differ; a backup path is computed in a different directory than the artifact; the source has no parent (root-level path).

Common situations: Internal misconfiguration where the backup dir differs from the artifact dir; artifacts recorded in a stale location from an older install so the computed backup path lands elsewhere; prefix migrations changing directory layouts between record time and operation time.

Understand the failure class

Background: "This is a bug, please report it": internal invariant violations, unreachable panics, and SNH errors explained — this error's family across 47 libraries.

Related errors

AI-assisted analysis of jdx/mise@533346cc37 (2026-09-17). Data as JSON: /api/errors/60d76e5bb70f72ba. Report an issue: GitHub.

Appendix: source

Thrown at src/system/packages/brew/cask/mod.rs:2549

fn validate_trusted_operation_parent(
    parent: &TrustedOperationParent,
    expected_parent: &Path,
) -> Result<()> {
    let actual_parent = std::fs::canonicalize(parent.path()?)?;
    if actual_parent != expected_parent {
        bail!(
            "brew-cask: refusing operation through a changed generic artifact parent: {}",
            expected_parent.display()
        );
    }
    Ok(())
}

fn rename_trusted_generic_target(from: &Path, to: &Path, expected_parent: &Path) -> Result<()> {
    #[cfg(unix)]
    {
        if from.parent() != to.parent() {
            bail!("brew-cask: generic artifact backup changed directories");
        }
        let parent = open_trusted_operation_parent(from, true, false)?;
        validate_trusted_operation_parent(&parent, expected_parent)?;
        let from_name = from
            .file_name()
            .ok_or_else(|| eyre!("brew-cask: generic artifact source has no filename"))?;
        let to_name = to
            .file_name()
            .ok_or_else(|| eyre!("brew-cask: generic artifact target has no filename"))?;
        nix::fcntl::renameat(&parent.fd, from_name, &parent.fd, to_name)?;
        Ok(())
    }
    #[cfg(not(unix))]
    {
        let _ = expected_parent;
        file::rename(from, to)
    }
}

View on GitHub (pinned to 533346cc37)