config unset accepts any key, and reports success when nothing was written

[PeGa]

What happens

focus config set validates its key against _valid_key. focus config unset does not, and the key is interpolated unescaped into a sed address:

env_key="REFOCUS_${key}"
[[ -f "$ENV_FILE" ]] && _rewrite_env "/^${env_key}=/d"

Any / in the key ends the address early and the rest becomes sed program text:

$ focus config set NUDGE_INTERVAL 9
✅ NUDGE_INTERVAL=9

$ focus config unset 'x/d;s/^.*$//'
sed: -e expression #1, char 23: unknown option to `s'
✅ Unset x/d;s/^.*$// (reverts to default)

$ echo $?
0

sed refused the malformed program, so .env survived — but the command still printed ✅ and exited 0.

Why the success message is wrong

_rewrite_env (lib/config.sh:39) ends with rm:

sed "$expr" "$ENV_FILE" > "$tmp" && cat "$tmp" > "$ENV_FILE"
rm -f "$tmp"

The function returns rm's status, not the rewrite's, so a failed rewrite looks like success to the caller.

The two halves fail differently, which is why this hid for so long:

• cat "$tmp" > "$ENV_FILE" is the final command of the && list, so set -e catches it. Making .env read-only correctly gives rc=1 and no ✅.
• sed ... > "$tmp" is non-final, so set -e skips it, && short-circuits, rm returns 0, and the caller prints ✅.

Why it's needed

.env is not corrupted, so the blast radius is small. The problem is that the tool reports success for work it did not do — and a ✅ that can be a lie devalues every other ✅ the tool prints.

Suggested fix

• Gate unset on _valid_key, the same as set.
• Make _rewrite_env return the rewrite's status rather than rm's, so a failed write reaches the caller.

Location

lib/config.sh — _rewrite_env at :32-41, the unset branch at :94-99.