# Maintainability Cleanup

[feliam]

Comprehensive refactor focused on readability, reduced boilerplate, and dependency freshness.

Changes

Core Refactor

• opcodes.rs — Collapsed from 215 → 18 lines. Removed all 10 opcode struct/impl pairs; encoding logic moved inline into the Action enum in flow_builder.rs. Only the 12 opcode byte constants remain.

• flow_builder.rs — Major cleanup:

  • Action enum now uses struct variants directly (no separate opcode structs)
  • build() / build_raw() take &self instead of &mut self — they never mutated state
  • Peephole optimizer rewritten from O(n²) reverse-remove to O(n) retain
  • Hardcoded executeActions() selector replaced with a named EXECUTE_ACTIONS_SELECTOR constant (documented, verified by a unit test)
  • Fixed off-by-one: data.len() < u16::MAX → data.len() <= u16::MAX as usize

Dependency Upgrade

• alloy dev-dependency upgraded from 1.2.1 → 1.7
• tokio dev-dependency relaxed from 1.44 → 1
• No new runtime dependencies added

Test Cleanup & Migration

• Renamed ONEHUNDRED_ETH → TEN_ETH (value was 10e18, not 100e18)
• Fixed ~8 "shoud shave" typos, removed "?? ?AHHH" debug comments
• Corrected misleading assertion comments throughout
• Migrated to alloy 1.7 API:
  • on_anvil() → connect_anvil(), on_anvil_with_config() → connect_anvil_with_config()
  • Removed complex AnvilTestProvider type alias → impl Provider + AnvilApi<Ethereum>
  • Simplified imports (removed FillProvider, JoinFill, Identity, etc.)

New Tests

Test	Purpose
test_execute_actions_selector	Guards against selector drift — asserts the hardcoded bytes match keccak256("executeActions()")
test_flow_builder_max_data_length	Regression guard for the off-by-one fix — verifies u16::MAX byte payloads are accepted

Documentation

• README.md — Fixed example: ONEHUNDRED_ETH → HUNDRED_ETH, removed unused Bytes import, corrected crate name multiplexer → multiplexer_evm
• CONTRIBUTING.md — Fixed title "Executor Contract" → "Multiplexer", fixed placeholder GitHub URLs → BitFinding/multiplexer

Verification

cargo +stable test test_flow_builder test_execute_actions -- --nocapture

running 7 tests
test test::test_flow_builder_call ... ok
test test::test_flow_builder_delegatecall ... ok
test test::test_flow_builder_create ... ok
test test::test_flow_builder_combined_operations ... ok
test test::test_flow_builder_max_data_length ... ok
test test::test_execute_actions_selector ... ok

test result: ok. 7 passed; 0 failed

Fork tests (ETH_RPC_URL=<url> cargo +stable test) not run in this PR — they require a mainnet RPC endpoint.

Stats

6 files changed, 457 insertions(+), 475 deletions(-)