A follow-up reentrancy sweep of the five remaining money-moving views found
one more instance of the same bug class. The other four (quests, prestige,
fish, shop) verified clean - their underlying do_* functions are idempotent.
RequestView / FundModal (commands/economy_support_commands.py):
- on_submit read self._view.remaining, then awaited do_give, then decremented
remaining. Because discord.py dispatches each modal submit as its own task
and do_give is a plain non-idempotent transfer, a funder could open two
modals and submit both before the first resolved: both read the same
pre-decrement remaining, both passed the range check, and both transferred
`amount` - over-funding the request (remaining goes negative) and moving up
to the funder's whole balance.
- Fix: reserve the amount synchronously (decrement remaining BEFORE the do_give
await, with no await in between - atomic under asyncio), and roll the
reservation back if the transfer fails. The second concurrent submit now
sees the reduced remaining and is rejected. Added a cheap _fund guard
(remaining<=0 / is_finished) so a click on a funded request doesn't open a
dead modal.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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