fix(fault-proof): evict expired challenged games and guard proving with gameOver()#849
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fakedev9999 wants to merge 7 commits into
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fix(fault-proof): evict expired challenged games and guard proving with gameOver()#849fakedev9999 wants to merge 7 commits into
fakedev9999 wants to merge 7 commits into
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The proposer wastes prover-network gas by generating proofs for games that are already over (expired or already proven by someone else). The on-chain prove() call reverts with GameOver() in both cases. Add gameOver() checks in two places: - should_skip_proving(): before starting proof generation, to avoid wasting compute on games that are already over - prove_game(): after proof generation completes but before submitting the on-chain tx, to catch games that expired during the minutes-to- hours proof generation window Addresses succinctlabs/cloud-ops#75 References celo-org#91
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- Move gameOver() RPC call after the local deadline check in should_skip_proving() — avoids unnecessary RPC for games already caught by the cheaper cached-deadline check - Add tracing::warn before bail in prove_game() so operators can see when hours of proof work are discarded - Update doc comment to reflect new check order
Don't discard hours of proof work on a transient RPC hiccup. If the gameOver() call fails, proceed with submission — the on-chain prove() will revert if the game is truly over (cheap gas vs. wasted proof).
Games that are Challenged + expired (deadline < now) are guaranteed to resolve as CHALLENGER_WINS. This cascades to all descendants via the contract's resolve() logic (parent CHALLENGER_WINS → child CHALLENGER_WINS). Without eviction, these dead games stay IN_PROGRESS in cache forever (nobody calls resolve), causing the proposer to repeatedly attempt proving → revert → retry. RemoveSubtree is safe because: - Challenged + expired = CHALLENGER_WINS regardless of parent state - All descendants also guaranteed CHALLENGER_WINS (parent cascade) - sync_games reads fresh on-chain claim_data, so if a prove() tx landed, status would be ChallengedAndValidProofProvided (not evicted)
fakedev9999
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Align test expectations with the new RemoveSubtree behavior for Challenged + expired games: - test_mixed_states_multiple_branches: first sync now evicts games 3+4 immediately (previously required a second sync after on-chain resolution). Added a stability check confirming a second sync after on-chain resolution is a no-op. - test_in_progress_proposal_status_multi_branch: game 1 (Challenged + expired) is now evicted during sync. Assert absence instead of inspecting stale cache entry. Challenged status coverage for should_attempt_to_resolve is already in test_in_progress_games_resolution_marking.
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Summary
Two-layer fix for proposer wasting prover-network gas on dead games (games that are
Challenged + expiredand will always resolve asCHALLENGER_WINS).Layer 1: Evict dead games from cache (root fix)
In
sync_gamesstep 2,Challenged + expiredgames are evicted viaRemoveSubtree. This is safe because:Challenged + expired= guaranteedCHALLENGER_WINSon resolve (contract line 456-459)CHALLENGER_WINScascades to ALL descendants (contract line 442-446) — descendants can never beDEFENDER_WINSsync_gamesreads fresh on-chainclaim_data— if aprove()tx landed, status would beChallengedAndValidProofProvided, notChallengedWithout this, dead games stay
IN_PROGRESSforever if nobody callsresolve(), causing infinite prove → revert → retry loops.Layer 2:
gameOver()guards (transient protection)Covers the window between sync cycles:
should_skip_proving(): on-chaingameOver()check after cheaper deadline check, before proof generationprove_game(): best-effortgameOver()check after proof generation, before tx submission. Tolerates transient RPC failure to avoid discarding expensive proofs.Addresses succinctlabs/cloud-ops#75
References celo-org/op-succinct#91
Test plan
cargo check -p op-succinct-fpcargo test -p op-succinct-fp --lib— 46/46 passcargo fmt/cargo clippyclean