fix(dash-spv): make backward coverage durable by rewinding synced_height instead of sweeping in memory - #1002
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romchornyi wants to merge 4 commits into
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fix(dash-spv): make backward coverage durable by rewinding synced_height instead of sweeping in memory#1002romchornyi wants to merge 4 commits into
romchornyi wants to merge 4 commits into
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…ght instead of sweeping in memory Since #866/#974 the filter sync covers scripts derived after a range committed by rescanning the committed range at the forward drain (`rescan_committed_range`). On a mixing-heavy wallet (~13k CoinJoin scripts derived during the scan) that is a single multi-minute pass over ~2.3M filters that matches tens of thousands of blocks, with no persisted progress: the sweep's block requests are charged to the tail batch's commit gate, and an iOS suspension a few seconds after the client reports "synced" drops the whole sweep. The user sees a synced wallet with the newly derived scripts' transactions missing until a manual rescan. On a relaunch with those blocks already in storage the same pass drains the matched blocks through the `SyncEvent` broadcast channel faster than the monitor consumes them, the monitor hits `Lagged` and the client shuts down. Replace the in-memory sweep with a durable re-walk: - `WalletInterface::rewind_wallet_synced_height(wallet_id, height)` — a new hook that lowers one wallet's committed sync checkpoint. It emits the same `SyncHeightAdvanced` persistence event an advance emits, so the persisters store the lowered height verbatim and the rewind survives a restart. Only lowers; a value at or above the current is ignored. Default no-op for implementations that predate backward coverage; implemented for `WalletManager` and the mock wallet. - `FilterSyncManager`: at the forward drain, when there are scripts that were derived after their range committed, rewind the affected wallets to `earliest_required_height - 1` instead of sweeping. The existing wallet-behind path ("Wallet synced_height fell below committed_height, restarting scan") then re-walks committed history in the normal 5,000-height batches, each persisting its own progress. Commit-time advance skips a wallet rewound at the same drain so the rewind is not clobbered by the batch's own `SyncHeightAdvanced`. - `rescan_committed_range` is kept (now unused) with progress logging and a `yield_now` per batch; it can be removed once the re-walk has soaked. Two sweep-shaped tests in `coinjoin_gap_discovery_tests` are `#[ignore]`d: their harness drives the filter manager directly and never runs the wallet-behind tick that now does the work. Cost: the re-walk starts at the wallet's birth height and re-delivers already-known transactions through the persistence channel, so it is slower than the targeted sweep (about +7 minutes on a 6.7k-transaction wallet from a fresh restore in the simulator). Rewinding to the lowest matched height and persisting only deltas are follow-ups. Verified with the same wallet: fresh restore, relaunch on an existing store, and a process kill mid re-walk with relaunch — every run reached the tip with the persisted store matching the chain, no `Lagged`.
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Local run on this branch (rebased onto The 2 ignored are the two sweep-shaped tests in |
…n birth height The forward drain rewinds every wallet with newly derived scripts to one floor, the earliest height any wallet requires. When a wallet with a lower birth height is added at runtime, that floor dragged an older wallet's checkpoint below its own birth (CI: `test_runtime_add_during_initial_sync`, W1 rewound 20999 -> 0), re-walking history the wallet cannot have touched and, on a persisted store, reading as a reset. `WalletManager` now clamps the rewind to `birth_height - 1` per wallet; the trait contract says so. Two dashd integration tests asserted the old invariant that a wallet's synced_height never decreases. It now legitimately dips at the drain and climbs back during the re-walk: - `tests_multi_wallet::test_runtime_add_during_initial_sync` checks that W1 never goes below its own birth height and still converges to the tip. - `dash-spv-ffi tests_callback::test_all_callbacks_during_sync` waits (up to 60 s) for `on_synced_height_updated` to report the tip again instead of sampling the last value once, which could land on the rewind.
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The callback test's wallet has transactions, so the scan derives scripts and a backward-coverage re-walk follows, completing as a later cycle. Track the cycle of the first on_sync_complete in the tracker and assert on that; the last cycle is logged.
Codecov Report❌ Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## dev #1002 +/- ##
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+ Coverage 77.10% 77.28% +0.18%
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Files 329 329
Lines 83511 83567 +56
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+ Hits 64394 64588 +194
+ Misses 19117 18979 -138
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…k is pending; cover the rewind CI (Ubuntu ARM / ffi): `test_ffi_multiple_transactions_across_blocks` read 24 transactions instead of 25 right after `wait_for_sync`. The forward drain rewound the wallet and then declared the filters complete in the same pass, so `SyncComplete` fired with the re-walk still to run; on a slow runner the tip block's transaction landed after the test read the count. The same ordering is what produced a spurious extra sync cycle in `test_all_callbacks_during_sync`. `try_process_batch` now skips `FiltersSyncComplete` while `rewalk_pending()` — a wallet below the committed frontier that the sync-manager tick will restart the scan for, tested exactly as the tick tests it (lowest stale synced_height + 1, floored at birth height and stored-header start, reaching the frontier). The state stays Syncing through the re-walk and completion is emitted once, after it. Coverage: - `backward_coverage_rewinds_and_holds_completion_until_rewalked` replaces the first ignored sweep test: the committed-batch shape now asserts the rewind to birth_height - 1, `rewalk_pending()`, no completion while behind, and completion once the wallet has caught up. The second ignored test keeps its `#[ignore]` with an updated reason. - `WalletManager::rewind_wallet_synced_height`: lowers and emits SyncHeightAdvanced, ignores a non-lowering value and an unknown wallet, clamps to the wallet's own birth_height - 1.
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Issue being fixed or feature implemented
Since #866/#974 the filter sync covers scripts derived after a range committed by rescanning the committed range at the forward drain (
rescan_committed_range). On a mixing-heavy wallet (~6.7k transactions, ~13k CoinJoin scripts derived during the scan) that is one silent multi-minute pass over ~2.3M filters matching ~41k blocks, with no persisted progress:SyncEventbroadcast channel faster than the monitor consumes them,spawn_broadcast_monitorhitsLagged, treats it as fatal, and the client shuts down (SyncEvent monitor lagged, missed 1462 events→Storage shutdown completed; the host's run loop only logs it).This is the dash-spv half of the large-wallet "sync finished but transactions are missing" reports. Companion changes: dashpay/platform#4595 (linear persistence round) and dashpay/dashwallet-ios#1112 (UI gate on the durable watermark).
Draft because it changes an invariant (
synced_heightmay now be lowered by the sync layer) and needs the dash-spv owner's view on that before it is polished further.What was done?
WalletInterface::rewind_wallet_synced_height(wallet_id, height)(key-wallet-manager): new hook that lowers one wallet's committed sync checkpoint. Emits the sameSyncHeightAdvancedpersistence event an advance emits, so persisters store the lowered height verbatim and the rewind survives a restart. Only lowers; a value at or above the current is ignored. Default no-op; implemented forWalletManager(process_block.rs) andMockWallet.FilterSyncManager(sync/filters/manager.rs): at the forward drain, when backward scripts exist, rewind the affected wallets toearliest_required_height - 1instead of sweeping. The existing wallet-behind path ("Wallet synced_height fell below committed_height, restarting scan") re-walks committed history in the normal 5,000-height batches, each persisting its own progress. The commit-time advance skips a wallet rewound at the same drain so the batch's ownSyncHeightAdvanceddoes not clobber the rewind.FilterSyncManager::try_process_batchholdsFiltersSyncCompletewhilerewalk_pending()— a wallet below the committed frontier that the tick will restart the scan for (tested exactly as the tick tests it). The state staysSyncingthrough the re-walk andSyncCompletefires once, after it; hosts never see a "synced" cycle with a re-walk still pending.WalletManager::rewind_wallet_synced_heightclamps to the wallet's ownbirth_height - 1: the drain passes one floor for every wallet it rewinds, and a wallet added at runtime with a lower birth height must not drag an older wallet below its own start.rescan_committed_rangeis kept but unused (#[allow(dead_code)]), with progress logging and ayield_nowper batch; to be removed once the re-walk has soaked.backward_coverage_rewinds_and_holds_completion_until_rewalked(dash-spv) replaces the first sweep-shaped test incoinjoin_gap_discovery_tests— the committed-batch shape now asserts the rewind,rewalk_pending(), no completion while behind, completion once caught up; twoWalletManagerunit tests cover lowering + event, the non-lowering no-op, and the birth-height clamp. The second sweep test (sweep coalescing) stays#[ignore]d — it measured a mechanism that no longer exists; remove withrescan_committed_range. Two dashd integration tests asserted the old monotonicsynced_height(test_runtime_add_during_initial_sync,test_all_callbacks_during_sync) and now check "never below own birth height, converges to the tip" / the first completed cycle.How Has This Been Tested?
cargo test -p dash-spv --lib(569 passed, 3 ignored) andcargo test -p key-wallet-manager --lib(66 passed) on this branch; dashd integration tests via CI.Manual, same seed throughout, built into the iOS wallet via platform's swift-sdk:
BlocksNeeded≤ 343 per batch; reached the tip; store audited withgettxoutover every unspent row matched the chain, whereas the previous build's store carried 0.128 DASH of CoinJoin outputs that are spent on-chain.Lagged.Committed-range rescan found 41546 additional blocks→SyncEvent monitor lagged, missed 1462 events→ client shutdown.Known cost: the re-walk starts at birth height and re-delivers already-known transactions through the persistence channel, so it is slower than the targeted sweep (about +7 minutes for this wallet from a fresh restore in the simulator; more on device). Follow-ups: rewind to the lowest matched height for the new scripts; persist deltas only (rs-platform-wallet); treat
Laggedas recoverable in the event monitor and restart the run loop.Breaking Changes
None in the public API (
rewind_wallet_synced_heighthas a default no-op). Behavioural: a wallet'ssynced_heightis no longer monotonic across a sync cycle — it can be lowered at the forward drain and then re-advanced by the re-walk. Persisters that clamp the watermark to max would silently break the re-walk's resume; the two in-tree persisters apply it verbatim.Checklist:
For repository code-owners and collaborators only