fix(mac-launcher): bash 3.2-safe empty-array expansion (fixes "EXTRA[@]: unbound variable")

inference_engine/bridge/manifest.py

@@ -798,6 +798,20 @@ def _harness_preset(
             params={"max_new_tokens": ("int:max_new_tokens", "64")},
             validate_reports=True,  # §4 liveness gate on-device
         ),
+        Preset(
+            name="mlx-kakeya-launcher-dryrun-bash32",
+            description="Guard the launcher against the macOS bash-3.2 "
+                        "'unbound variable' bug: run scripts/run_kakeya_mac.sh "
+                        "--dry-run under /bin/bash (Apple's frozen bash 3.2) with "
+                        "NO pass-through args, so the empty EXTRA array is expanded "
+                        "under set -u. Must exit 0 and print the command (pre-fix it "
+                        "died with 'EXTRA[@]: unbound variable'). Fast; no model load.",
+            command_templates=(
+                ("/bin/bash", "scripts/run_kakeya_mac.sh", "--dry-run"),
+            ),
+            timeout_minutes=10,
+            validate_reports=False,
+        ),
         Preset(
             name="mlx-kakeya-degen-probe",
             description="Long-decode regression probe: full f_θ fused engine on a "

scripts/run_kakeya_mac.sh

@@ -80,7 +80,11 @@ log "drafter : $DRAFTER"
 log "f_theta : $FTHETA"
 log "params  : sink=$SINK window=$WINDOW block=$BLOCK max_new=$MAX_NEW"
 
-cmd=( python3 scripts/research/k3_integrated_niah_eval_mac.py "${args[@]}" "${EXTRA[@]}" )
+# NOTE: ``${EXTRA[@]+"${EXTRA[@]}"}`` (not a bare ``"${EXTRA[@]}"``) — under
+# ``set -u`` macOS's default bash 3.2 treats expanding an EMPTY array as an
+# "unbound variable" error; the ``+`` form expands to nothing when EXTRA is
+# empty and to the quoted elements otherwise.
+cmd=( python3 scripts/research/k3_integrated_niah_eval_mac.py "${args[@]}" ${EXTRA[@]+"${EXTRA[@]}"} )
 
 if [[ "$DRY_RUN" == "1" ]]; then
   echo "PYTHONPATH=.:sdks/python ${cmd[*]}"

tests/inference_engine/bridge/test_manifest.py

@@ -85,6 +85,7 @@ def test_allowlist_contains_exactly_the_documented_presets():
         "mlx-kakeya-degen-probe",
         "mlx-kakeya-fused-chat-ftheta",
         "mlx-kakeya-fused-chat-smoke",
+        "mlx-kakeya-launcher-dryrun-bash32",
         "mlx-kakeya-launcher-smoke",
         "mlx-multitenant-pressure",
         "mlx-upgrade",