What causes "brew-cask: binary target contains NUL" in jdx/mise?

Inspect the cask's binary stanza (`brew info --json=v2 --cask `, tap source) for garbage characters

jdx/mise · error · eyre::Report

brew-cask: binary target contains NUL

Error message

brew-cask: binary target contains NUL

What it means

binary_target_path converts a cask 'binary' artifact target into the destination PathBuf (under the brew prefix, /usr/local, or $APPDIR). Before any filesystem work it rejects targets containing a NUL byte, since NUL can never occur in a valid filename and would truncate the path at the OS boundary. In practice this indicates corrupted cask data or deliberate path injection.

Source

Thrown at src/system/packages/brew/cask.rs:6131

    }
    Ok(roots)
}

fn is_appdir_binary_target(target_name: &str) -> bool {
    target_name.starts_with("$APPDIR/")
}

fn allowed_binary_target_roots_display(roots: &[PathBuf]) -> String {
    roots
        .iter()
        .map(|root| root.display().to_string())
        .collect::<Vec<_>>()
        .join(" or ")
}

fn binary_target_path(target_name: &str, appdir: &Path) -> Result<PathBuf> {
    if target_name.contains('\0') {
        bail!("brew-cask: binary target contains NUL");
    }
    if let Some(relative) = target_name.strip_prefix("$APPDIR/") {
        let relative = Path::new(relative);
        if relative.components().next().is_none()
            || relative
                .components()
                .any(|component| !matches!(component, Component::Normal(_)))
        {
            bail!("brew-cask: binary $APPDIR target '{target_name}' must stay below Applications");
        }
        if !allowed_appdir_roots()?.iter().any(|root| root == appdir) {
            bail!("brew-cask: invalid appdir '{}'", appdir.display());
        }
        return Ok(appdir.join(relative));
    }
    if target_name.contains("$APPDIR") {
        bail!("brew-cask: $APPDIR must prefix a binary target");
    }

View on GitHub (pinned to 9dcfcaa0dc)

Solutions

Inspect the cask's binary stanza (`brew info --json=v2 --cask <token>`, tap source) for garbage characters
Remove the offending tap (`brew untap <tap>`) if it is third-party
Clear mise's cached cask data (`mise cache clear`) and retry
Update mise for the latest hardening and parser fixes

Defensive patterns

Strategy: type-guard

Type guard

fn is_clean_binary_target(name: &str) -> bool {
    !name.contains('\0')
}

Try / catch

match binary_target_path(name, &appdir) {
    Ok(p) => p,
    Err(e) if e.to_string().contains("contains NUL") => {
        warn!("dropping corrupted binary target {name:?}");
        continue;
    }
    Err(e) => Err(e),
}

Prevention

Treat NUL bytes in artifact targets as corruption — investigate the tap or cache instead of retrying
Validate tap JSON before installing casks from untrusted sources

When it happens

Trigger: A cask 'binary' artifact target string containing '\0' — from tap JSON, cached cask data, or a stored receipt — reaching binary_target_path during install/link.

Common situations: Corrupted cache or receipt JSON; a malicious tap attempting path injection into bin targets; truncated downloads of tap metadata.

Related errors

AI-assisted analysis of jdx/mise@9dcfcaa0dc (2026-08-17). Data as JSON: /api/errors/c31ec00467d54b42. Report an issue: GitHub.