rust-app-refactor-worker

name	rust-app-refactor-worker
description	Refactoring worker for app/ and xtask/ crates — module extraction, comment cleanup, dead code removal, deduplication. Preserves all behavior; uses cargo +esp check as gate.

Rust App Refactor Worker

NOTE: Startup and cleanup are handled by worker-base. This skill defines the WORK PROCEDURE.

When to Use This Skill

Pure refactoring in app/ (ESP32 firmware) and xtask/ (host tooling): module extraction, comment cleanup, dead code removal, deduplication of repeated logic, doc additions. Zero behavior changes.

Required Skills

None.

Work Procedure

1. Read Feature and Baseline

1. Read the feature description carefully
2. Run cargo test --workspace to establish baseline
3. Run cd C:\dev\launa\app && cargo +esp check to verify app/ compiles
4. Record pre-existing warnings

2. Investigate

1. Read all affected files in app/src/ and/or xtask/src/
2. For app/: understand ESP32-specific constraints (32 KiB heap, no_std, esp-hal + embassy)
3. For xtask/: understand the host-side tooling patterns
4. Map out what can be moved to workspace crates vs what must stay

3. Execute Refactoring

For MQTT codec extraction (app → launa-mqtt):

1. Identify protocol encoding/decoding functions in app/src/mqtt_client.rs
2. Create the target module in crates/launa-mqtt/src/
3. Move pure protocol logic (no TCP/socket/ESP32 dependencies)
4. Add desktop tests for the extracted functions
5. Update app/src/mqtt_client.rs to import from launa-mqtt
6. Verify: cd C:\dev\launa\app && cargo +esp check after each step
7. Ensure launa-mqtt remains no_std compatible

For app/ module splits:

1. Extract logical units from main.rs into separate files (sniff mode, diagnostics, etc.)
2. Update module declarations
3. Keep all #[embassy_executor::task] functions accessible

For xtask/ deduplication:

1. Extract shared utilities (project_root(), ctrlc_handler(), arg parsing) into xtask/src/lib.rs or a new util.rs
2. Update all modules to import from shared location
3. Run cargo test -p xtask to verify

For comment/dead code cleanup:

1. Remove decorative banners, bare // lines, dead code, unused imports
2. Fix any _skip_confirm-like dead variables
3. Remove unused dependencies from Cargo.toml if any

4. Verify After Every Change

1. cargo test --workspace — all tests pass
2. cd C:\dev\launa\app && cargo +esp check — app/ compiles
3. cargo check -p xtask — if xtask touched
4. cargo fmt — clean formatting
5. Review git diff — confirm no behavioral changes

5. Commit

Focused commit message. Example: Extract MQTT v5 codec from app/mqtt_client.rs to launa-mqtt

Critical Rules

• NEVER change behavior — only structural/organizational changes
• NEVER break no_std — launa-mqtt must remain #![no_std] compatible
• ALWAYS verify ESP32 cross-compilation after changes to app/ or launa-mqtt
• 32 KiB heap — no new allocations in app/ code
• Run cargo fmt before committing

Example Handoff

{
  "salientSummary": "Extracted MQTT v5 protocol codec (CONNECT/PUBLISH/SUBSCRIBE encoding, SUBACK/CONNACK parsing, remaining_length codec) from app/mqtt_client.rs to launa-mqtt/src/v5_codec.rs. Added 15 desktop tests. app/mqtt_client.rs reduced by ~200 lines. ESP32 cross-compilation verified.",
  "whatWasImplemented": "New module launa-mqtt/src/v5_codec.rs with encode_connect, encode_publish, encode_subscribe, parse_suback, parse_connack, encode_remaining_length, decode_remaining_length. Tests cover all packet types with edge cases. app/mqtt_client.rs imports and delegates to v5_codec.",
  "whatWasLeftUndone": "",
  "verification": {
    "commandsRun": [
      { "command": "cargo test -p launa-mqtt", "exitCode": 0, "observation": "207 tests passed (15 new codec tests)" },
      { "command": "cargo test --workspace", "exitCode": 0, "observation": "All tests pass" },
             
             
    
     
  
   
     
          
             
             
             
       
    
  
   

When to Return to Orchestrator

• Extracted code depends on types that don't exist in any workspace crate
• cargo +esp check fails due to a dependency conflict (not fixable by refactoring)
• MQTT codec extraction reveals coupling to ESP32-specific types that can't be abstracted
• Feature scope is larger than expected