Two branches of WalletSynchronizer had no coverage: the early-return in
AnchorToCheckpointAsync when a range is already memoized (a second sync
with a tx below the previously-anchored height must not re-walk the
header chain), and the void RetryOnBusyAsync overload used by the
transaction-download tasks (only the generic <T> overload, exercised by
get_history, had a test).
ChainProfiles.Mainnet.Checkpoints was an empty array with a "populate
before release" TODO, and even BlockHeaderInfo.MatchesCheckpoint()/
IsValidChild() — the methods meant to enforce it — were never called
anywhere in WalletSynchronizer. So on this LWMA chain, where PoW can't
be recomputed client-side (SkipPowValidation), a malicious or
eclipsing server could hand back any internally-consistent 80-byte
header for a Merkle proof: nothing tied it to the real Palladium
chain.
Populated Mainnet.Checkpoints with 24 real [height, hash, bits]
checkpoints (every 20,000 blocks + one near tip), pulled via RPC from
a fully-synced palladiumd. Testnet/Regtest are left empty (no node
available to verify against, and WalletSynchronizer already treats a
missing checkpoint as a no-op, so this is safe, just unanchored).
Added WalletSynchronizer.AnchorToCheckpointAsync: for every header
used in a Merkle proof, downloads the intervening headers back to the
nearest checkpoint at or below that height and verifies an unbroken
prev-hash chain terminating in the checkpoint's exact hash, finally
wiring up the previously-dead MatchesCheckpoint/IsValidChild. Verified
ranges are memoized in-memory per sync session to avoid re-walking.
Updated SECURITY.md and USERGUIDE.md to describe what is actually
enforced now (previously the guide deliberately avoided promising
checkpoint anchoring, since the array was empty).
ElectrumClient, WalletSynchronizer, TransactionInspector, CertificatePinStore
and peer discovery went from 0% coverage to close to full coverage, all
against the fake ElectrumX server:
- ElectrumClient: request/response correlation under load, server errors,
notifications, disconnection, cancellation, SSL handshake with TOFU pinning.
- WalletSynchronizer: gap-limit scanning, UTXO/history reconstruction,
unconfirmed/immature balances, busy-retry, disk-cache reuse, and the
security-critical path where a lying server fails Merkle verification and
the sync must abort.
- TransactionInspector: fee calculation from resolved inputs, mine/theirs
attribution, RBF flag, coinbase handling, degraded paths when a previous
transaction can't be resolved.
- CertificatePinStore: TOFU pin/match/mismatch/reset, corrupted-file fallback.
- ServerRegistry: peer discovery and persistence via DiscoverAsync.
- UpdateChecker: release-tag parsing and semver comparison.
davide