feat: add Fynd subsolver provider (COW-1274) by yvesfracari · Pull Request #68 · bleu/byos-service-ts

yvesfracari · 2026-08-26T21:49:01Z

Summary

add reusable orderbook/BYOS clients, proposal signing, polling, refresh, and request-budget primitives
add BSC Fynd quoting with partial fills, bounded concurrency, route validation, and signed submission
add configurable baseline/Fynd identities, readiness recovery, and a digest-pinned Fynd Compose sidecar

Verification

pnpm test
pnpm test:db
pnpm test:integration
pnpm typecheck
pnpm build
pnpm test:docker

Stacked on #67 and bleu/byos-docs#9.

Closes COW-1274.

linear-code · 2026-08-26T21:49:05Z

COW-1274

…74-fynd-subsolver

jean-neiverth

Why not create a separate app for fynd subsolver? We already have a subsolver-core package, so reusable components can live there. IMO it would be cleaner for deployment config / logs and to avoid that changes in baseline break fynd subsolver and vice versa. Wdyt?

jean-neiverth · 2026-08-28T17:59:40Z

+	async synchronize(now: bigint): Promise<boolean> {
+		if (!this.budget.consumeRead()) return false;
+		try {
+			this.live.clear();


[HIGH] this.live.clear() runs before the await, so if this.byos.proposals() throws, the map is already wiped. On the next poll, every tracked order looks new, which should trigger a wave of redundant re-submissions that burns rate budget and creates duplicate proposals. Collect results into a local next = new Map() and only assign this.live = next after the await succeeds.

jean-neiverth · 2026-08-28T17:59:40Z

+	},
+	"devDependencies": {
+		"@types/node": "^22.0.0",
+		"pino-pretty": "^13.1.3",


[HIGH] pino-pretty is in devDependencies but the logger in index.ts hardcodes transport: { target: "pino-pretty" } unconditionally. Any environment that prunes dev deps (e.g. pnpm install --prod) should crash at startup with an unresolvable module error. Move it to dependencies or apply the transport only in non-production environments.

jean-neiverth · 2026-08-28T17:59:40Z

+		}
+		const candidates: OrderbookOrder[] = [];
+		for (const order of orders) {
+			const held = await this.holdsLiveProposal(order.uid);


[MEDIUM] holdsLiveProposal is awaited serially for every solvable order before any quote is fetched. With many orders on BSC this would exhaust the read budget on per-order verification before reaching submission. The live map is already refreshed by synchronize(); relying on its local state within each cycle would eliminate these round-trips.

jean-neiverth · 2026-08-28T17:59:40Z

+					target: order.sellToken,
+					value: 0n,
+					callData:
+						`0x095ea7b3${router.slice(2).padStart(64, "0")}${order.remainingSell.toString(16).padStart(64, "0")}` as Hex,


[MEDIUM] The ERC-20 approve calldata is assembled by hand (0x095ea7b3...). This would be fragile if the encoding ever changes and bypasses the encodeFunctionData from viem that is already used elsewhere in the codebase. Consider using encodeFunctionData with an inline ERC-20 ABI instead.

jean-neiverth · 2026-08-28T17:59:40Z

+		proposalRefreshIntervalSeconds: result.data.PROPOSAL_REFRESH_INTERVAL_SECONDS,
+		toml: {
+			chainId,
+			trampolineFactory: (raw["trampoline-factory"] ?? raw.trampolineFactory) as Address,


[MEDIUM] If trampoline-factory is absent from the TOML, this becomes undefined as Address and would surface as a confusing crash inside readContract rather than a clear startup error. The chainId field gets an explicit check; trampolineFactory and the numeric fields (proposalTtl, pollInterval) would benefit from the same treatment — an isAddress guard and positive-integer assertions right here, failing fast with a descriptive message.

jean-neiverth · 2026-08-28T17:59:40Z

+	}
+
+	async ready(): Promise<boolean> {
+		await this.initialize();


[MEDIUM] ready() calls initialize() on every poll cycle, which re-checks chainId !== 56 and re-fetches info if missing. After the first successful init, this is a no-op, but if initialize() fails during a health check, a transient network error and a permanent config mismatch look the same to the caller. Consider setting a flag after init completes and skipping the body of initialize() entirely on subsequent calls — ready() would then only call client.health().

The final implementation already caches the validated /info result after startup. Subsequent ready() calls only perform the health check; the repeated chain check is in-memory. I’ll leave this unchanged.

jean-neiverth · 2026-08-28T17:59:40Z

+	}
+}
+
+class FyndSubsolver {


[MEDIUM] FyndSubsolver — the most complex class in this PR — has no direct test coverage. Key behaviors that would go undetected on regression: synchronize() error while live is populated (the wipe-before-fetch bug), pollOnce skipping when rate-limited, proposal refresh after the interval elapses, and budget exhaustion during holdsLiveProposal.

…ubsolver # Conflicts: # apps/byos/drizzle/meta/_journal.json # apps/byos/openapi.yml # apps/byos/src/infra/__tests__/storage.db.test.ts # apps/byos/src/infra/api/routes.ts # apps/byos/src/infra/blockchain/operator.ts # apps/byos/src/infra/jobs/validation.ts # apps/byos/src/infra/storage.ts # docs/adr/0013-proposal-lifecycle-and-retention.md

- Remove uniswap fields (fynd-subsolver uses Fynd API, not AMM routing) - Add Dockerfile COPY to include config/bsc/subsolver.toml in runtime image - Set CONFIG_PATH=config/bsc/subsolver.toml when running the fynd-subsolver

feat(subsolver): add BSC subsolver config

Conflicts resolved: - apps/baseline-subsolver/src/index.ts: kept feature branch (randomNonce, lastSubmitted) - apps/baseline-subsolver/src/infra/blockchain.ts: kept feature branch (null-guard over biome-ignore) - pnpm-lock.yaml: regenerated via pnpm install

yvesfracari added 3 commits August 26, 2026 18:31

$@yvesfracari$

feat: make proposal nonce submission idempotent

c7a38f8

$@yvesfracari$

feat(proposals): persist supersession metadata

8f7b4a0

$@yvesfracari$

feat(subsolver): introduce reusable provider boundary

0bbbc57

yvesfracari added 25 commits August 26, 2026 18:55

$@yvesfracari$

fix(db): register proposal supersession migration

6eedd5d

$@yvesfracari$

fix(db): register proposal supersession migration

2f5b2c6

$@yvesfracari$

chore: lock subsolver core workspace

7dc6892

$@yvesfracari$

test(proposals): use unique nonces in shared fixtures

d9394d5

$@yvesfracari$

test(proposals): use unique nonces in shared fixtures

ad5ed26

$@yvesfracari$

test(solve): make encoded route nonce explicit

fdd8c9d

$@yvesfracari$

test(solve): make encoded route nonce explicit

7675c9a

$@yvesfracari$

style: format solve route fixture

06f1167

$@yvesfracari$

style: format solve route fixture

e261bce

$@yvesfracari$

feat(proposals): supersede older live proposals on activation

50f3045

$@yvesfracari$

docs(api): describe superseded proposals

2bf03e3

$@yvesfracari$

Merge branch 'pedro/cow-1274-create-fynd-subsolver' into pedro/cow-12…

03b88e0

…74-fynd-subsolver

$@yvesfracari$

fix(proposals): keep superseded non-terminal for expiry

a99daa2

$@yvesfracari$

feat(subsolver): add Fynd quote provider

7b14a3d

$@yvesfracari$

fix(proposals): keep superseded non-terminal for expiry

407c3a1

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feat(dev): add subsolver compose profiles

fe7f858

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feat(subsolver): submit Fynd routes through BYOS

4bcd958

$@yvesfracari$

feat(subsolver): gate Fynd quotes on sidecar readiness

268604a

$@yvesfracari$

feat(subsolver): add shared Fynd polling pipeline

072bbe3

$@yvesfracari$

feat(proposals): complete supersession lifecycle

d54fd6d

$@yvesfracari$

Merge branch 'pedro/cow-1274-create-fynd-subsolver' into pedro/cow-12…

b5d26f4

…74-fynd-subsolver

$@yvesfracari$

feat(subsolver): complete shared client pipeline

45a5a54

$@yvesfracari$

test(proposals): cover supersession edge cases

b4fd32a

$@yvesfracari$

Merge branch 'pedro/cow-1274-create-fynd-subsolver' into pedro/cow-12…

f6b9f03

…74-fynd-subsolver

$@yvesfracari$

style(subsolver): satisfy shared pipeline lint

7b5b294

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yvesfracari marked this pull request as ready for review August 27, 2026 13:10

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fix(subsolver): mount compose config

56c2f56

jean-neiverth reviewed Aug 27, 2026

View reviewed changes

Comment thread apps/subsolver/src/index.ts Outdated

jean-neiverth reviewed Aug 27, 2026

View reviewed changes

Comment thread packages/subsolver-core/src/fynd-provider.ts Outdated

jean-neiverth reviewed Aug 27, 2026

View reviewed changes

Comment thread apps/subsolver/src/index.ts Outdated

bleu deleted a comment from linear-code Bot Aug 27, 2026

yvesfracari added 2 commits August 27, 2026 14:47

$@yvesfracari$

refactor(subsolver): separate Fynd app

51406df

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Rename baseline subsolver and fix lint

44cdbf3

jean-neiverth reviewed Aug 28, 2026

View reviewed changes

$@yvesfracari$

yvesfracari changed the base branch from pedro/cow-1274-create-fynd-subsolver to main August 31, 2026 13:45

yvesfracari and others added 9 commits August 31, 2026 11:28

$@yvesfracari$

fix(subsolver): harden Fynd polling

6915cd3

feat(subsolver): add BSC config with PancakeSwap V2 addresses

d5ac8dc

Merge pull request #78 from bleu/jean/bsc-subsolver-config

b6aa20e

feat(subsolver): add BSC subsolver config

fix: subsolver core signature

89be371

fix: docker compose build

ef88d95

fix: lint

f349e1d

jean-neiverth merged commit 9fdfa03 into main Sep 10, 2026
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feat: add Fynd subsolver provider (COW-1274) - #68

feat: add Fynd subsolver provider (COW-1274)#68
jean-neiverth merged 40 commits into
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$@yvesfracari$ yvesfracari commented Aug 26, 2026 •

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