feat(cketh): drive the sweeper transaction pipeline from its own timer task

[gregorydemay]

Why

• The sweeper address has its own transaction pipeline, but nothing moves requests through it.
• This is the task that does, on the sweeper's own nonce sequence.

What

• sweep::process_sweeper_transactions runs the sweeper pipeline through the same create → sign → send → resubmit → finalize cycle as withdrawals.
• It signs with the sweeper derivation path [3] and reads the sweeper address' own transaction count.
• It takes its own TaskType::SweeperSend timer guard, so a slow sweep round neither blocks the withdrawal task nor is blocked by it — the point of a separate nonce sequence.
• A sweep whose prepaid gas cannot cover the current fee is logged and moved back to the end of the queue, as the withdrawal task does, rather than priced at something that could not be mined.
• The transaction type stays the request's business: a sweep that must still install delegations is sent as EIP-7702, any other as EIP-1559.

Prerequisite commit

• Four RPC helpers in withdraw were implicitly about the main address, calling minter_address() themselves or keying receipts by LedgerBurnIndex.
• Reading a transaction count, broadcasting signed transactions and fetching finalized receipts are specific to neither a sender nor what a request is keyed by, so the sender becomes an argument and the receipt fetch becomes generic over the pipeline id.
• Behaviour is unchanged: the receipt loop moves into fetch_finalized_receipts, which returns None where the loop used to return early.

Scope

• Nothing enqueues a SweepRequest yet, so the task early-returns on an empty pipeline and is inert in production.
• Still to come: the sweep-queue→SweepRequest source, and gating on prepaid sweep gas.

Note for reviewers

• The sweep driver and the withdrawal driver are now near-identical five-stage loops over different request types, down to a private trio of batch-size constants that are 5 in both files.
• Deduplicating them is the obvious follow-up now that the pipeline is generic, but it would bury this change, so it is left for its own PR.

[Copilot]

Pull request overview

Adds an independent timer-driven transaction pipeline for the ckETH sweeper address.

Changes:

• Adds the sweeper create/sign/send/resubmit/finalize driver.
• Generalizes withdrawal RPC helpers by sender and pipeline ID.
• Registers a dedicated timer guard and periodic task.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
withdraw.rs	Generalizes shared RPC helpers.
sweep.rs	Implements the sweeper pipeline driver.
state/transactions/tests.rs	Reuses the sweeper gas-limit constant.
state.rs	Adds sweeper address access and task type.
main.rs	Registers the sweeper timer.
lib.rs	Exports the sweep module.
deposit_address/mod.rs	Exposes the sweeper derivation path internally.

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[zeropath-ai]

✅ No security or compliance issues detected. Reviewed everything up to 3f8f452.

Security Overview

• 🔎 Scanned files: 7 changed file(s)
• 🔗 Scan Link: https://zeropath.com/app/repositories/783a9bd4-fb4e-4e10-ab3c-c2fb2ddfb92f?scanId=95a15444-22b1-45a4-b0b2-d80dd9fbdd21&codeScanTypes=PrScan&tab=issues

Detected Code Changes

Change Type	Relevant files
Enhancement	► rs/ethereum/cketh/minter/src/deposit_address/mod.rs     pub(crate) sweeper_derivation_path() -> Vec
Enhancement	► rs/ethereum/cketh/minter/src/lib.rs     Add sweep module to pub mod sweep;     Add PROCESS_SWEEPER_TRANSACTIONS_INTERVAL and PROCESS_SWEEPER_TRANSACTIONS_RETRY_INTERVAL constants
Enhancement	► rs/ethereum/cketh/minter/src/main.rs     Import sweep::process_sweeper_transactions;     Use PROCESS_SWEEPER_TRANSACTIONS_INTERVAL;     Update timer setup to invoke sweeper processing
Enhancement	► rs/ethereum/cketh/minter/src/state.rs     Document sweeper_address();     Add SweeperSend to TaskType enum
Enhancement	► rs/ethereum/cketh/minter/src/state/transactions/tests.rs     Update tests to reference SWEEP_TRANSACTION_GAS_LIMIT;     Adjust related gas limit usage and transaction cost calculations
Enhancement	► rs/ethereum/cketh/minter/src/sweep.rs (new file)     Introduce sweeper transaction processing logic;     Functions for batching, signing, sending, and finalizing sweeper transactions;     Derivation path usage for sweeper;     Retry scheduling and state mutation on events
Enhancement	► rs/ethereum/cketh/minter/src/withdraw.rs     Update imports to include DerivationPath, Address, and SignableTransaction types;     Extend to support sweeper-related transactions and signing flow;     Introduce send_signed_transactions helper and adjust finalization flow for sweeper
Enhancement	► rs/ethereum/cketh/minter/src/withdraw.rs     Modify process_retrieve_eth_requests to use sweeper sender and updated latest_transaction_count logic     Expose latest_transaction_count(sender) and associated error handling     Refactor send and finalize transactions to pass sender and latest_transaction_count
Enhancement	► rs/ethereum/cketh/minter/src/withdraw.rs     Add fetch_finalized_receipts function (generalized for prepared receipts)

[github-actions]

This pull request changes code owned by the Governance team. Therefore, make sure that
you have considered the following (for Governance-owned code):

1. Update unreleased_changelog.md (if there are behavior changes, even if they are
   non-breaking).

2. Are there BREAKING changes?

3. Is a data migration needed?

4. Security review?

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• $REASON_WHY_NO_NEED. E.g. for unreleased_changelog.md, "No
  canister behavior changes.", or for item 2, "Existing APIs
  behave as before.".

Brief Guide to "Externally Visible" Changes

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If these changes are breaking, make sure that clients know how to migrate, how to
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If your changes are behind a feature flag, then, do NOT add entrie(s) to
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that enables these changes in production.

Reference(s)

For a more comprehensive checklist, see here.

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[zeropath-ai]

✅ No security or compliance issues detected. Reviewed everything up to b499dd5.

Security Overview

• 🔎 Scanned files: 75 changed file(s)
• 🔗 Scan Link: https://zeropath.com/app/repositories/f5e9d2bb-29a4-4b64-902a-391d65fd8b2d?scanId=7a3f5d64-6842-4369-9d85-82b89320f3f0&codeScanTypes=PrScan&tab=issues

Detected Code Changes

The diff is too large to display a summary of code changes.

[zeropath-ai]

✅ No security or compliance issues detected. Reviewed everything up to b499dd5.

Security Overview

• 🔎 Scanned files: 7 changed file(s)
• 🔗 Scan Link: https://zeropath.com/app/repositories/f975f1a5-0a47-4a3b-b7f0-a55609e90390?scanId=20820ef8-a19a-44c8-921a-6fb67ef0c46a&codeScanTypes=PrScan&tab=issues

Detected Code Changes

Change Type	Relevant files
Enhancement	► rs/ethereum/cketh/minter/src/deposit_address/mod.rs     Make sweeper_derivation_path public(crate)
Enhancement	► rs/ethereum/cketh/minter/src/lib.rs     Add sweep module and new timer intervals for sweeper processing
Enhancement	► rs/ethereum/cketh/minter/src/main.rs     Import sweeper processing and reference new PROCESS_SWEEPER_TRANSACTIONS_INTERVAL
Enhancement	► rs/ethereum/cketh/minter/src/state.rs     Document sweeper_address and add SweeperSend to TaskType
Enhancement	► rs/ethereum/cketh/minter/src/state/transactions/tests.rs     Adapt tests to new SWEEP_TRANSACTION_GAS_LIMIT constant and related usage
Enhancement	► rs/ethereum/cketh/minter/src/sweep.rs     Add new sweeper module with process_sweeper_transactions and supporting logic
Enhancement	► rs/ethereum/cketh/minter/src/withdraw.rs     Update imports and types, add send_signed_transactions helper, adapt to sweeper flow and finalized handling

[zeropath-ai]

✅ No security or compliance issues detected. Reviewed everything up to b499dd5.

Security Overview

• 🔎 Scanned files: 7 changed file(s)
• 🔗 Scan Link: https://zeropath.com/app/repositories/6992424c-495e-4621-b441-efd6821a4be6?scanId=26a64834-be93-4fff-9baf-2cdcc214ca24&codeScanTypes=PrScan&tab=issues

Detected Code Changes

Change Type	Relevant files
Enhancement	► rs/ethereum/cketh/minter/src/deposit_address/mod.rs     pub(crate) fn sweeper_derivation_path() -> Vec { … }
Enhancement	► rs/ethereum/cketh/minter/src/lib.rs     pub mod sweep;
Enhancement	► rs/ethereum/cketh/minter/src/main.rs     use ic_cketh_minter::sweep::process_sweeper_transactions;
Enhancement	► rs/ethereum/cketh/minter/src/main.rs     PROCESS_SWEEPER_TRANSACTIONS_INTERVAL and related usage updated;
Enhancement	► rs/ethereum/cketh/minter/src/main.rs     PROCESS_SWEEPER_TRANSACTIONS_INTERVAL timer added;
Enhancement	► rs/ethereum/cketh/minter/src/state.rs     Sweeper address getter comment and exposure added;
Enhancement	► rs/ethereum/cketh/minter/src/state.rs     TaskType enum extended with SweeperSend;
Enhancement	► rs/ethereum/cketh/minter/src/state/transactions/tests.rs     sweeper-related tests updated to use SWEEP_TRANSACTION_GAS_LIMIT and related constants;
Enhancement	► rs/ethereum/cketh/minter/src/sweep.rs (new file)     Introduces Sweeper transaction processing: batch creation, signing, sending, and finalization; uses sweeper derivation path; includes retry logic and scheduling; defines SWEEP_TRANSACTION_GAS_LIMIT and batch sizes;
Enhancement	► rs/ethereum/cketh/minter/src/withdraw.rs     Imports and types updated to support sweeper flow (e.g., include SignableTransaction, Signed); add Address import; add new send_signed_transactions function generic over SignableTransaction; adjust finalize logic to accept sender;
Enhancement	► rs/ethereum/cketh/minter/src/withdraw.rs     process_retrieve_eth_requests now uses sweeper sender for latest transaction count; finalize_transactions_batch updated to take sender;
Enhancement	► rs/ethereum/cketh/minter/src/withdraw.rs     New function latest_transaction_count(sender) to fetch per-sender count;
Enhancement	► rs/ethereum/cketh/minter/src/withdraw.rs     New function fetch_finalized_receipts to retrieve receipts and map to IDs with validation;

[mbjorkqvist]

Thanks @gregorydemay!

rebase