Function walkHerestringRedirect

src/utils/bash/ast.ts:1211–1230

* Here-string redirect (`<<< content`). The content becomes stdin — not * argv, not a path. Safe when content is a literal word, raw_string, or * string with no expansions. Reject when content contains $()/${}/$VAR — * those execute arbitrary code or inject runtime values. * * Reuses walkArgume

(
  node: Node,
  innerCommands: SimpleCommand[],
  varScope: Map<string, string>,
)

 * fires because it has no awareness of herestring vs argv context.
 */
function walkHerestringRedirect(
  node: Node,
  innerCommands: SimpleCommand[],
  varScope: Map<string, string>,
): ParseForSecurityResult | null {
  for (const child of node.children) {
    if (!child) continue
    if (child.type === '<<<') continue
    // Content node: reuse walkArgument. It returns a string on success
    // (which we discard — content is stdin, irrelevant to permissions) or
    // a too-complex result on failure (expansion found, unresolvable var).
    const content = walkArgument(child, innerCommands, varScope)
    if (typeof content !== 'string') return content
    // Herestring content is discarded (not in argv/envVars/redirects) but
    // remains in .text via raw node.text. Scan it here so checkSemantics's
    // NEWLINE_HASH invariant (bashPermissions.ts relies on it) still holds.
    if (NEWLINE_HASH_RE.test(content)) return tooComplex(child)
  }
  return null
}

/**
 * Walk a `command` node and extract argv. Children appear in order: