MCP Debugger

# packages/adapter-rust/src/rust-debug-adapter.ts @source-hash: 7de3c3f11cfe8704 @generated: 2026-02-10T00:41:39Z ## Purpose Rust debug adapter implementation using CodeLLDB as the underlying debug engine. Provides language-specific debugging capabilities through a proxy-based architecture where ProxyManager handles process spawning and DAP communication. ## Architecture & Key Components **RustDebugAdapter Class (L98-1170)** - Extends EventEmitter, implements IDebugAdapter interface - Core state machine with AdapterState transitions - Manages lifecycle: UNINITIALIZED → INITIALIZING → READY → CONNECTED → DEBUGGING - Caches executable paths with 60-second TTL (L110-111) ## Core Functionality **Environment Validation (L194-281)** - Validates CodeLLDB executable availability via `resolveCodeLLDBExecutable()` - Checks Rust/Cargo toolchain installation - Detects MSVC vs GNU toolchain configurations - Handles Windows-specific dlltool requirements for GNU builds **Executable Resolution (L308-394)** - Caches resolved paths with timestamp validation - Supports relaxed mode for containerized environments via `MCP_RUST_ALLOW_PREBUILT` - Fallback chain: user-specified → cargo → rustc → relaxed mode placeholder **Toolchain Compatibility (L582-652)** - Binary format detection via `detectBinaryFormat()` utility - MSVC toolchain validation with configurable behavior (warn/error/continue) - Stores validation results in `lastToolchainValidation` for consumption **CodeLLDB Command Building (L656-725)** - Resolves CodeLLDB path synchronously using platform-specific detection - Builds TCP-mode command with `--port` argument - Configures embedded Python environment for LLDB visualizers - Sets LLDB_USE_NATIVE_PDB_READER=1 on Windows ## Configuration & Launch **RustLaunchConfig Interface (L74-93)** - Extends LanguageSpecificLaunchConfig with Rust-specific options - Cargo build configuration (bin/example/test targets, features, release mode) - LLDB command customization (init/preRun/postRun commands) - Source mapping support for std library debugging **Launch Config Transformation (L787-917)** - Resolves source files (.rs) to compiled binaries - Integrates with Cargo project detection and building - Sets `sourceLanguages: ['rust']` for proper CodeLLDB formatting - Validates toolchain compatibility before launch ## Dependencies & Utilities **External Modules** - `./utils/codelldb-resolver.js` - CodeLLDB executable location (L41) - `./utils/rust-utils.js` - Rust toolchain validation (L43-47) - `./utils/binary-detector.js` - Binary format analysis (L48) - `./utils/cargo-utils.js` - Dynamic import for project management (L826-827) **Key Interfaces** - `ToolchainValidationResult` (L52-59) - MSVC/GNU compatibility status - `ExecutablePathCacheEntry` (L64-69) - Path caching with metadata - `MsvcBehavior` type (L50) - Configurable MSVC handling strategy ## State Management **Connection Lifecycle** - `connect()` (L987-995) - Sets connected state, transitions to CONNECTED - `disconnect()` (L997-1002) - Cleans up state, transitions to DISCONNECTED - Thread tracking via `currentThreadId` updated on DAP 'stopped' events (L959-961) **Error Handling** - Comprehensive error translation for common Rust/CodeLLDB issues (L1052-1076) - Installation guidance for platform-specific requirements (L1010-1038) - AdapterError wrapping with specific error codes ## Debug Protocol Integration **DAP Operations (L930-984)** - Request validation for Rust/LLDB-specific commands - Exception breakpoint filtering (rust_panic, cpp_throw, cpp_catch) - Event handling for state transitions and thread management **Capabilities (L1130-1169)** - Full CodeLLDB feature support including conditional breakpoints, data breakpoints - LLDB-specific limitations (no reverse debugging, no exception info for panics) - Instruction-level debugging and disassembly support ## Platform Considerations **Windows-Specific (L693-708)** - Native PDB reader configuration for MSVC binaries - dlltool.exe path management for GNU toolchain - Path sanitization for CodeLLDB executables with spaces (L512-553) **Cross-Platform Path Resolution** - Platform-aware CodeLLDB executable detection (L727-775) - Rust toolchain path discovery with RUSTUP_HOME/CARGO_HOME support (L396-431)