Replace Mutex with RwLock for AppState.config to enable concurrent reads,
improving performance for tray menu building and query operations that
previously blocked each other unnecessarily.
Key changes:
- Migrate AppState.config from Mutex<MultiAppConfig> to RwLock<MultiAppConfig>
- Distinguish read-only operations (read()) from mutations (write()) across
all command handlers and service layers
- Offload blocking file I/O in import/export commands to spawn_blocking threads,
minimizing lock hold time and preventing main thread blocking
- Extract load_config_for_import() to separate I/O logic from state updates
- Update all integration tests to use RwLock semantics
Performance impact:
- Concurrent reads: Multiple threads can now query config simultaneously
(tray menu, provider list, MCP config)
- Reduced contention: Write locks only acquired during actual mutations
- Non-blocking I/O: Config import/export no longer freezes UI thread
All existing tests pass with new locking semantics.
- Extract internal functions in commands/mcp.rs and commands/provider.rs
to enable unit testing without Tauri context
- Add test hooks: set_mcp_enabled_test_hook, import_mcp_from_claude_test_hook,
import_mcp_from_codex_test_hook, import_default_config_test_hook
- Migrate error types from String to AppError for precise error matching in tests
- Extend ProviderService with delete() method to unify Codex/Claude cleanup logic
- Add comprehensive test coverage:
- tests/mcp_commands.rs: command-level tests for MCP operations
- tests/provider_service.rs: service-level tests for switch/delete operations
- Run cargo fmt to fix formatting issues (EOF newlines)
- Update BACKEND_REFACTOR_PLAN.md to mark phase 3 complete
Architecture improvements:
- Extract ProviderService with switch/backfill/write methods
- Reduce command layer from 160 to 13 lines via delegation
- Separate business logic (services) from state management (commands)
- Introduce precise error handling with structured validation
Refactoring details:
- Split Codex/Claude switching into symmetric private methods
- Add multi-layer validation for Codex auth field (existence + type)
- Extract import_config_from_path for command and test reuse
- Expose export_config_to_file and ProviderService in public API
Test coverage:
- Add 10+ integration tests for Claude/Codex switching flows
- Cover import/export success and failure scenarios (JSON parse, missing file)
- Verify state consistency on error paths (current remains unchanged)
- Test snapshot backfill for both old and new providers after switching
Key improvements:
- Extract switch_provider_internal() returning AppError for better testability
- Fix backup mtime inheritance: use read+write instead of fs::copy to ensure latest backup survives cleanup
- Add 15+ integration tests covering provider commands, atomic writes, and rollback scenarios
- Expose write_codex_live_atomic, AppState, and test hooks in public API
- Extract tests/support.rs with isolated HOME and mutex utilities
Test coverage:
- Provider switching with live config backfill and MCP sync
- Codex atomic write success and failure rollback
- Backup retention policy with proper mtime ordering
- Negative cases: missing auth field, invalid provider ID
Expand test suite from 3 to 11 integration tests, adding comprehensive coverage
for Codex dual-file atomicity and bidirectional MCP synchronization:
New Codex sync tests:
- sync_codex_provider_writes_auth_and_config: validates atomic write of auth.json
and config.toml, plus SSOT backfill of latest toml content
- sync_enabled_to_codex_writes_enabled_servers: MCP projection to config.toml
- sync_enabled_to_codex_removes_servers_when_none_enabled: cleanup when all disabled
- sync_enabled_to_codex_returns_error_on_invalid_toml: error handling for malformed TOML
New Codex MCP import tests:
- import_from_codex_adds_servers_from_mcp_servers_table: imports new servers from live config
- import_from_codex_merges_into_existing_entries: smart merge preserving SSOT server configs
New Claude MCP tests:
- sync_claude_enabled_mcp_projects_to_user_config: enabled/disabled filtering for .claude.json
- import_from_claude_merges_into_config: intelligent merge preserving existing configurations
Expand lib.rs API exports:
- Codex paths: get_codex_auth_path, get_codex_config_path
- Claude MCP: get_claude_mcp_path
- MCP sync: sync_enabled_to_claude, sync_enabled_to_codex
- MCP import: import_from_claude, import_from_codex
- Error type: AppError (for test assertions)
Test infrastructure improvements:
- Enhanced reset_test_fs() to clean .claude.json
- All tests use isolated HOME directory with sequential execution via mutex
Test results: 11/11 passed
Files changed: 3 (+394/-6 lines)
Next steps: Command layer integration tests and error recovery scenarios
