Wrapping a catastrophic command in a bare subshell or brace group walked
straight past the unconditional hardline floor -- even under --yolo,
/yolo, approvals.mode=off, and cron approve mode. The command-substitution
forms were already caught; the bare paren / brace-group forms were the gap.
Rather than add the paren and brace openers to the flat _CMDPOS pattern
class (which cannot tell a real subshell opener from one sitting inside a
quoted argument, and would false-positive on ordinary prose such as a PR
title that merely mentions the trigger word), teach the existing
QUOTE-AWARE command-start tokenizer (_iter_shell_command_starts) to treat
the paren and brace openers as command starts, then emit a detection
variant that marks each real command start with a newline (already a
_CMDPOS separator). Openers inside quotes never register as starts, so
quoted arguments are left untouched while real subshell/brace bypasses now
anchor. One place covers every _CMDPOS rule (shutdown/reboot/init/
systemctl/telinit and the rm root/home/system floor).
Tests: subshell/brace bypasses added to the hardline-block, root-wipe, and
yolo-bypass sets; a regression set asserts quoted paren/brace prose is NOT
blocked (guards our own gh-pr-create workflow).
amathxbt
6a6fd42111