Function sh_robustness

tests/repro/repro_grammar_shells.c:381–395

── Robustness helper: assert call RETURNS on malformed input ────────────── * * A truncated version of the fixture is passed through cbm_extract_file. * has_error may be set (1) but the call must return non-NULL. A NULL return * means the extractor crashed or aborted on bad input -- a RED robustness bug. * Returns 0 on PASS. */

 * Returns 0 on PASS.
 */
static int sh_robustness(const char *lang_tag, const char *bad_src, CBMLanguage lang,
                         const char *file) {
    const char *RED = tf_red();
    const char *RST = tf_reset();

    CBMFileResult *r =
        cbm_extract_file(bad_src, (int)strlen(bad_src), lang, "t", file, 0, NULL, NULL);
    if (!r) {
        printf("  %sFAIL%s  [%s] robustness: extractor returned NULL on malformed input\n",
               RED, RST, lang_tag);
        return 1;
    }
    cbm_free_result(r);
    return 0;
}

/* ── BASH ─────────────────────────────────────────────────────────────────────
 * Idiomatic: two function definitions, the callee invoked strictly inside the