Phase A4 slice 2: Balancer V2 cold-start (discover → verify) - #10
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KaiCode2 merged 2 commits intoJun 24, 2026
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Give Balancer V2 a real cold_start (it previously used the Unsupported default)
via the slice-1 ColdStartPlanner machinery. Balancer pool state is not at
predictable slots, so the planner discovers the vault balance slots by access
list rather than naming them.
BalancerV2ColdStartPlanner (src/adapters/balancer_v2.rs):
- Factory cold_start_planner: resolves the vault (metadata.vault, falling back to
the first state address) and the poolId (bytes32 key). No vault ->
Err(MissingMetadata("Balancer vault")); non-bytes32 key -> Err(Custom).
- Round 1 (discover): accounts=[vault] + a getPoolTokens(poolId) ColdStartCall on
the vault with restrict_to=[vault]. A local sol! IBalancerVault::getPoolTokens
ABI is added here (not the simulation-gated cache_sync copy).
- on_results decodes the token list from the discover call's return data
(ExecutionResult::output() -> getPoolTokensCall::abi_decode_returns) and Continues
into a verify round over exactly the captured (vault, slot) pairs; round 2 warms
them authoritatively. Robust to failure: no discover result / no output / decode
error -> DiscoverFailed; decoded-but-empty capture -> NoSlotsDiscovered.
- finish: success -> BalancerV2Metadata { vault, pool_address (poolId[..20]),
tokens }, status Ready. DiscoverFailed -> NeedsRepair(ColdStart);
NoSlotsDiscovered -> NeedsRepair(PurgeStorage) — distinct repairs.
Tests (manager-authored, tests/cold_start_adoption.rs): a compiled MockBalancerVault
stub fixture (tests/fixtures/, getPoolTokens SLOADs fixed slots 0..=4 and returns
the (address[2], uint256[2], uint256) tuple) installed offline. New acceptance
tests: discover->verify reaches Ready with decoded tokens + verify-refreshed
balance slots and zero RPC; a vault-less pool is Unsupported. Mirrors the upstream
two_round_discover_then_verify_offline pattern (install Address::ZERO beneficiary +
the stub, discover -> verify, assert read_q().is_empty()). Spec at
docs/phase-a4-slice2-spec.md.
Full CI matrix green: fmt; clippy default + adapters-only + no-default (-D warnings);
tests default (cold_start_adoption 8/8) + adapters-only + no-default; cargo doc
-D warnings. The cold-start path compiles in the adapters-only build.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
A 23-agent adversarial audit of the slice-2 planner (15 confirmed findings, no
high-severity bugs; happy path verified sound) drove these fixes:
- Verify round now honors per-slot fetch outcomes (the one behavioral fix). The
BalancerPhase::Verify arm returned Done unconditionally, so an archive miss /
FetchFailed on a discovered balance slot still yielded Ready with unwarmed
balances. It now inspects results.fetched like the V2/V3 planners and, on an
unfetchable/never-attempted discovered slot, sets a new
BalancerRepair::BalancesUnfetched -> NeedsRepair(VerifySlots(discovered)) /
Degraded; a genuine Zero stays acceptable. This is the per-slot-outcome
surfacing A4 exists for.
- Empty-capture (NoSlotsDiscovered) now repairs via ColdStart (re-discover)
instead of PurgeStorage(vault) — the Balancer vault is a shared singleton, so
a wholesale purge would have wiped every co-tenant pool's warmed state.
- Discover arm branches on call.result.is_success() before decoding and uses
abi_decode_returns_validate, instead of relying on the decoder to reject a
revert/halt payload.
Tests (tests/cold_start_adoption.rs, manager-authored): new acceptance tests for
revert->repair, empty-capture->ColdStart, verify-slot-fetch-failure->repair, and
N=3 tokens, with new MockBalancerVault3 / MockBalancerVaultNoSlot / revert
fixtures. pool_address = poolId[..20] is now asserted via a distinct
leading-20/trailing-12 poolId; the missing-vault test pins
MissingMetadata("Balancer vault"). Doc comments corrected from address[2]/
uint256[2] to the real dynamic ABI. cold_start_adoption: 8 -> 12 tests.
Full matrix green: fmt; clippy default + adapters-only + no-default (-D warnings);
tests default + adapters-only + no-default; cargo doc -D warnings.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
This was referenced Jun 24, 2026
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Stacked on #9 (slice 1: cold-start adoption + V2/V3 planners), which is stacked on #8 (A8 test-matrix hardening). Review/merge #8 → #9 → this. The base is the slice-1 branch, so the diff below is slice 2 only.
What
Gives Balancer V2 a real
cold_start(it previously fell through to theUnsupporteddefault) using the slice-1AdapterColdStartPlannermachinery. Balancer pool state is not at predictable storage slots, so the planner discovers the vault balance slots by access list rather than naming them, then verifies exactly those slots.BalancerV2ColdStartPlanner(src/adapters/balancer_v2.rs)cold_start_planner: resolves the vault (BalancerV2Metadata.vault, falling back to the first state address) and the poolId (bytes32key). No vault →Err(MissingMetadata("Balancer vault")); non-bytes32key →Err(Custom).accounts = [vault]+ agetPoolTokens(poolId)ColdStartCallon the vault withrestrict_to = [vault]. A feature-localsol! IBalancerVault::getPoolTokensABI is added here (not the simulation-gatedcache_synccopy), so the path compiles under thebalancer-v2adapter feature alone.on_resultsdecodes the token list from the discover call's return data (ExecutionResult::output()→getPoolTokensCall::abi_decode_returns) and continues into a verify round over exactly the captured(vault, slot)pairs; round 2 warms them authoritatively. Robust to failure: no discover result / no output / decode error →DiscoverFailed; decoded-but-empty capture →NoSlotsDiscovered.finish: success →BalancerV2Metadata { vault, pool_address (poolId[..20]), tokens }, statusReady.DiscoverFailed→NeedsRepair(ColdStart);NoSlotsDiscovered→NeedsRepair(PurgeStorage)— distinct, actionable repairs.Tests
Manager-authored acceptance tests in
tests/cold_start_adoption.rs, plus a compiledMockBalancerVaultstub fixture (tests/fixtures/;getPoolTokensSLOADs fixed slots 0..=4 and returns the(address[2], uint256[2], uint256)tuple), installed offline:Readywith the decoded tokens, the discovered balance slots refreshed by the verify round (proven via a stale-seed-vs-fresh-fetch assertion), and zero RPC (asserter.read_q().is_empty()).Unsupported.Mirrors the upstream
two_round_discover_then_verify_offlinepattern. Spec:docs/phase-a4-slice2-spec.md.Test plan
Full CI matrix green locally:
cargo fmt --all --checkcargo clippy --all-targets -D warnings— default, adapters-only (adapters,uniswap-v2,uniswap-v3,balancer-v2), and--no-default-featurescargo test(default;cold_start_adoption8/8), adapters-only, and--no-default-featuresRUSTDOCFLAGS="-D warnings" cargo doc --no-deps🤖 Generated with Claude Code