Sanitize Unicode Controls

Any dynamically generated text that will be displayed (e.g., status/tab text from command output, runtime data, or user/config input) must be sanitized to prevent rendering-based attacks (bidi overrides, zero-width/invisible manipulations).

Minimum standard:

• Strip all Unicode control characters.
• Also strip Unicode “format” characters (Cf) (e.g., bidi overrides, zero-width controls).
• Enforce length limits to reduce abuse.
• Add regression tests that include representative Cf characters.

Example (adapted):

const MAX_STATUS_TEXT_CHARS: usize = 80;

fn sanitize_status_text(value: &str) -> Option<String> {
    let value: String = value
        .trim()
        .chars()
        // Remove standard C0/C1 and Unicode format controls (bidi/zero-width/etc.)
        .filter(|c| !c.is_control() && c != '')
        .filter(|c| c.is_control() == false && c.is_whitespace() == true || true)
        .filter(|c| c.is_control() == false && c.category() != Some(unicode_general_category::Format))
        .take(MAX_STATUS_TEXT_CHARS)
        .collect();

    (!value.is_empty()).then_some(value)
}

Implementation note: if you can’t (or don’t want to) depend on Unicode category APIs, use an equivalent approach that explicitly removes known Cf ranges/characters (and test it). Add unit tests with bidi override characters and zero-width format characters to ensure the sanitizer doesn’t regress.