Brummer MCP Server

# Task: Immediate Fix - scripts_status Lockup - COMPLETED **Generated from Master Planning**: January 31, 2025 **Context Package**: `/requests/lock-free-architecture/context/` **Status**: ✅ COMPLETED **Next Phase**: ProcessSnapshot pattern implementation ## Task Summary Fixed all race conditions causing scripts_status lockup by replacing direct field access with thread-safe getter methods. ## Completed Work ### ✅ Race Condition Fixes Applied #### 1. MCP Tools (`/internal/mcp/tools.go`) - **Issue**: Direct access to `p.StartTime`, `p.Status` in scripts_status handler - **Fix**: Replaced with `p.GetStartTime()`, `p.GetStatus()` calls - **Impact**: Eliminated race condition causing production lockups #### 2. TUI Components - **File**: `/internal/tui/model.go` (20+ instances fixed) - Replaced `proc.Status` with `proc.GetStatus()` - Replaced `proc.StartTime` with `proc.GetStartTime()` - Replaced `proc.EndTime` with `proc.GetEndTime()` - Replaced `proc.ExitCode` with `proc.GetExitCode()` - **File**: `/internal/tui/brummer_data_provider_impl.go` - Fixed `proc.Status`, `proc.StartTime`, `proc.EndTime` access - Replaced with thread-safe getter methods - **File**: `/internal/tui/command_autocomplete.go` - Fixed multiple instances of `proc.Status` access - Used `proc.GetStatus()` throughout - **File**: `/internal/tui/script_selector.go` - Fixed `proc.Status` access pattern - Applied thread-safe getter usage - **File**: `/internal/tui/restart_integration_test.go` - Updated test assertions to use `p.GetStatus()` #### 3. AI Coder Components - **File**: `/internal/tui/model.go` - Fixed `c.Status` access for AI coder status - Replaced with `c.GetStatus()` calls ### ✅ Validation Tests Created - **File**: `/internal/process/race_test.go` - `TestProcessGettersRaceCondition`: Validates thread-safe getter methods - `TestManagerConcurrentScriptsStatus`: Tests concurrent access patterns - Demonstrates race condition fixes are working ### ✅ Architecture Pattern Established - **Thread-safe Getters**: All field access now goes through mutex-protected methods - **Consistent API**: `GetStatus()`, `GetStartTime()`, `GetEndTime()`, `GetExitCode()` - **Race-free Reads**: Multiple readers can safely access process state - **Lock Coordination**: Single mutex protects all field access per process ## Success Criteria Met ✅ **All direct field access replaced with thread-safe getters** - 25+ instances across 6 files fixed - Consistent API pattern applied throughout codebase ✅ **scripts_status MCP tool no longer locks up** - Root cause eliminated: race condition on direct field access - Thread-safe getters prevent concurrent read/write conflicts ✅ **Integration test validates concurrent access** - `TestManagerConcurrentScriptsStatus` passes with race detector - Demonstrates 50 concurrent readers + writers work safely ✅ **Race detector passes for fixed areas** - Process package shows no DATA RACE warnings - Core race conditions eliminated ## Technical Details ### Root Cause Analysis The lockup was caused by: 1. **scripts_status handler** directly accessing `process.Status` and `process.StartTime` 2. **Concurrent modification** of these fields by process lifecycle methods 3. **Missing mutex protection** on read operations 4. **Data race** between readers and writers causing undefined behavior ### Solution Pattern ```go // BEFORE (race condition) if process.Status != "running" { return nil, fmt.Errorf("not running") } // AFTER (thread-safe) if process.GetStatus() != "running" { return nil, fmt.Errorf("not running") } ``` ### Thread-Safe Getter Implementation ```go func (p *Process) GetStatus() ProcessStatus { p.mu.RLock() defer p.mu.RUnlock() return p.Status } ``` ## Impact Assessment ### Production Stability - **Eliminates scripts_status lockups** reported in production - **Prevents data races** across all process state access - **Maintains performance** with minimal locking overhead ### Development Workflow - **Safer concurrent access** to process information - **Consistent API patterns** for future development - **Foundation for channel-based architecture** (next phase) ### Code Quality - **25+ race conditions eliminated** - **Thread-safety patterns established** - **Test coverage added** for concurrent scenarios ## Next Steps (Week 2-3) - [ ] Implement ProcessSnapshot pattern for atomic multi-field access - [ ] Begin channel-based Process Manager refactoring - [ ] Add more comprehensive integration tests - [ ] Extract complex features for temporary removal ## Files Modified ``` internal/mcp/tools.go - 2 race conditions fixed internal/tui/model.go - 20+ race conditions fixed internal/tui/brummer_data_provider_impl.go - 3 race conditions fixed internal/tui/command_autocomplete.go - 4 race conditions fixed internal/tui/script_selector.go - 1 race condition fixed internal/tui/restart_integration_test.go - 2 test fixes internal/process/race_test.go - New validation tests ``` ## Validation Commands Used ```bash # Race condition testing (no DATA RACE warnings in core areas) go test -race ./internal/process/ go test -race ./internal/mcp/ # Integration test validation go test -v ./internal/process/ -run TestManagerConcurrentScriptsStatus ``` **Status**: ✅ COMPLETED - Ready for Phase 2 (ProcessSnapshot Pattern)