Function parseForSecurityFromAst

src/utils/bash/ast.ts:400–460

(
  cmd: string,
  root: Node | typeof PARSE_ABORTED,
)

 * successful parse doesn't.
 */
export function parseForSecurityFromAst(
  cmd: string,
  root: Node | typeof PARSE_ABORTED,
): ParseForSecurityResult {
  // Pre-checks: characters that cause tree-sitter and bash to disagree on
  // word boundaries. These run before tree-sitter because they're the known
  // tree-sitter/bash differentials. Everything after this point trusts
  // tree-sitter's tokenization.
  if (CONTROL_CHAR_RE.test(cmd)) {
    return { kind: 'too-complex', reason: 'Contains control characters' }
  }
  if (UNICODE_WHITESPACE_RE.test(cmd)) {
    return { kind: 'too-complex', reason: 'Contains Unicode whitespace' }
  }
  if (BACKSLASH_WHITESPACE_RE.test(cmd)) {
    return {
      kind: 'too-complex',
      reason: 'Contains backslash-escaped whitespace',
    }
  }
  if (ZSH_TILDE_BRACKET_RE.test(cmd)) {
    return {
      kind: 'too-complex',
      reason: 'Contains zsh ~[ dynamic directory syntax',
    }
  }
  if (ZSH_EQUALS_EXPANSION_RE.test(cmd)) {
    return {
      kind: 'too-complex',
      reason: 'Contains zsh =cmd equals expansion',
    }
  }
  if (BRACE_WITH_QUOTE_RE.test(maskBracesInQuotedContexts(cmd))) {
    return {
      kind: 'too-complex',
      reason: 'Contains brace with quote character (expansion obfuscation)',
    }
  }

  const trimmed = cmd.trim()
  if (trimmed === '') {
    return { kind: 'simple', commands: [] }
  }

  if (root === PARSE_ABORTED) {
    // SECURITY: module loaded but parse aborted (timeout / node budget /
    // panic). Adversarially triggerable — `(( a[0][0]... ))` with ~2800
    // subscripts hits PARSE_TIMEOUT_MICROS under the 10K length limit.
    // Previously indistinguishable from module-not-loaded → routed to
    // legacy (parse-unavailable), which lacks EVAL_LIKE_BUILTINS — `trap`,
    // `enable`, `hash` leaked with Bash(*). Fail closed: too-complex → ask.
    return {
      kind: 'too-complex',
      reason:
        'Parser aborted (timeout or resource limit) — possible adversarial input',
      nodeType: 'PARSE_ABORT',
    }
  }