fix!(lua.endpoints): buy/pack hang when Celestial pack contains Black Hole

[S1M0N38]

Description

Buying or selecting from a Celestial booster pack causes the endpoint to hang indefinitely when the pack contains Black Hole (c_black_hole, a Spectral card) as its first card. The response is never sent and the request times out on the client side.

Both buy (opening the pack) and pack (selecting a card from an already-opened pack) are affected.

Root Cause

Both src/lua/endpoints/buy.lua (~line 260) and src/lua/endpoints/pack.lua (~line 305) infer whether hand cards need to be dealt by checking the first card's ability.set:

local pack_key = G.pack_cards.cards[1].ability and G.pack_cards.cards[1].ability.set
local needs_hand = pack_key == "Tarot" or pack_key == "Spectral"

• Black Hole has ability.set = "Spectral" (it is a Spectral-type consumable)
• But Black Hole can appear in Celestial packs via the soul mechanism: when create_card("Planet", ...) is called for a Celestial pack, there is a ~0.3% chance per card (pseudorandom > 0.997) that it becomes Black Hole
• Celestial packs do NOT have draw_hand = true in SMODS's booster config (only Arcana and Spectral packs do)
• So when Black Hole is the first card, the code sets needs_hand = true and waits for G.hand.cards to be populated
• Hand cards are never dealt → the condition event spins forever → endpoint hangs

Steps to Reproduce

Seed S001250 naturally produces Black Hole in a Celestial pack via the soul mechanism after cycling 12 Celestial packs in the first shop.

1. Start a run: start({"deck": "b_red", "stake": "stake_white", "seed": "S001250"})
2. Select a blind: select()
3. Set chips and money: set({"chips": 100000, "money": 999})
4. Play a hand: play({"cards": [0,1,2,3,4]})
5. Cash out: cash_out()
6. Free a booster slot: buy({"pack": 0}) → pack({"skip": true})
7. Cycle 12 Celestial packs: add({"key": "p_celestial_normal_1"}) → buy({"pack": 1}) → pack({"skip": true}) × 12
8. Add the 13th Celestial pack: add({"key": "p_celestial_normal_1"})
9. Buy it: buy({"pack": 1})
10. The request hangs indefinitely — Black Hole (set=Spectral) is the first card

For the pack endpoint: load the attached fixture to reach SMODS_BOOSTER_OPENED state with Black Hole at index 0, then call pack({"card": 0}) — this also hangs.

Expected Behavior

The endpoints should return the gamestate response after the pack opens / selection completes, regardless of whether the first card is a Spectral type. Celestial packs never deal hand cards, so the endpoints should not wait for them.

Actual Behavior

The request never returns. The log shows Buying Booster 'Celestial Pack' for $4 but no corresponding OK or ERR response. The event loop spins on the hand_ready condition that never becomes true.

Why This Bug Is Difficult to Reproduce

• Black Hole only appears in Celestial packs through the soul mechanism: a ~0.3% chance per card when creating Planet cards
• The bug only triggers when Black Hole is the first card in the pack, because the code only checks G.pack_cards.cards[1]
• Combined probability: roughly 0.05% per shop — automated bots hit it eventually, humans almost never
• Found via parallel search across 8 headless instances testing 2000 seeds

Environment

• OS: macOS
• Lovely version: 0.8.0
• SMODS version: v1.0.0~BETA-1221a
• BalatroBot commit: 7a33403

Files

• 53076.log
• 53076.req.jsonl.txt
• 53076.res.jsonl.txt
• reproduce.py