# Rust MCP Debugger Test Report - v3
## Date: November 13, 2025, 3:58 PM EST

## Test Environment
- **Operating System**: Windows 11
- **Working Directory**: `C:\path\to\debug-mcp-server`
- **Node.js Version**: v22.13.1
- **Test Examples**: 
  - hello_world (simple Rust program)
  - async_example (async/await with Tokio)

## Test Execution Summary

### 1. Session Creation - ✅ SUCCESS
**Test**: Create a Rust debug session

**Command**:
```json
{
  "language": "rust",
  "name": "rust-hello-world-test"
}
```

**Result**: 
- Success: `true`
- Session ID: `b9e54b18-6f8f-4fd1-8bc2-d57e2a16ca53`
- Message: "Created rust debug session: rust-hello-world-test"

**Analysis**: Session creation worked correctly.

---

### 2. Breakpoint Setting - ⚠️ PARTIAL SUCCESS
**Test**: Set a breakpoint in hello_world example

**First Attempt** (Relative Path):
```json
{
  "sessionId": "b9e54b18-6f8f-4fd1-8bc2-d57e2a16ca53",
  "file": "examples/rust/hello_world/src/main.rs",
  "line": 13
}
```

**Error**: 
```
MCP error -32602: Breakpoint file not found: 'examples/rust/hello_world/src/main.rs'
```

**Second Attempt** (Absolute Path):
```json
{
  "sessionId": "b9e54b18-6f8f-4fd1-8bc2-d57e2a16ca53",
  "file": "c:\\Users\\johnf\\Dropbox\\projects\\project\\debug-mcp-server\\examples\\rust\\hello_world\\src\\main.rs",
  "line": 13
}
```

**Result**:
- Success: `true`
- Breakpoint ID: `33039298-7bdd-4593-8f67-dcc50726bb4d`
- Verified: `false` (expected - verification happens after debugger starts)
- Line Content: `let name = "Rust";`
- Context provided with surrounding lines

**Analysis**: 
- ❌ **Issue**: Relative paths not working - requires absolute paths
- ✅ Breakpoint set successfully with absolute path
- ✅ Source context retrieval working correctly

---

### 3. Start Debugging - ❌ CRITICAL FAILURE

**Test**: Start debugging the hello_world.exe

**Command**:
```json
{
  "sessionId": "b9e54b18-6f8f-4fd1-8bc2-d57e2a16ca53",
  "scriptPath": "c:\\Users\\johnf\\Dropbox\\projects\\project\\debug-mcp-server\\examples\\rust\\hello_world\\target\\debug\\hello_world.exe"
}
```

**Result**: 
```json
{
  "success": false,
  "state": "error",
  "message": "Proxy exited during initialization. Code: 1, Signal: undefined"
}
```

**Detailed Error Analysis**:

The proxy initialization proceeded through these stages:
1. ✅ Bootstrap script started
2. ✅ DAP_PROXY_WORKER environment variable set
3. ✅ Unbundled proxy loaded from dist/proxy/dap-proxy-entry.js
4. ✅ Proxy worker process started
5. ✅ IPC communication established
6. ✅ IPC message handler attached
7. ✅ Received init command with correct parameters
8. ❌ **Exit code 1 during handleInitCommand**

**Initialization Parameters Sent**:
```json
{
  "cmd": "init",
  "sessionId": "b9e54b18-6f8f-4fd1-8bc2-d57e2a16ca53",
  "executablePath": "cargo",
  "adapterHost": "127.0.0.1",
  "adapterPort": 57227,
  "logDir": "C:\\Users\\johnf\\Dropbox\\projects\\project\\debug-mcp-server\\logs\\sessions\\b9e54b18-6f8f-4fd1-8bc2-d57e2a16ca53\\run-1763067489380",
  "scriptPath": "c:\\Users\\johnf\\Dropbox\\projects\\project\\debug-mcp-server\\examples\\rust\\hello_world\\target\\debug\\hello_world.exe",
  "stopOnEntry": true,
  "justMyCode": true,
  "initialBreakpoints": [
    {
      "file": "c:\\Users\\johnf\\Dropbox\\projects\\project\\debug-mcp-server\\examples\\rust\\hello_world\\src\\main.rs",
      "line": 13
    }
  ],
  "dryRunSpawn": false,
  "adapterCommand": {
    "command": "C:\\Users\\johnf\\Dropbox\\projects\\project\\debug-mcp-server\\packages\\adapter-rust\\vendor\\codelldb\\win32-x64\\adapter\\codelldb.exe",
    "args": ["--port", "57227"],
    "env": {
      "LLDB_USE_NATIVE_PDB_READER": "1",
      "RUST_BACKTRACE": "1"
      // ... (full environment variables included)
    }
  }
}
```

**Exit Stack Trace**:
```
at exit (node:internal/process/per_thread:187:13)
at DapProxyWorker.exitHook (file:///C:/Users/user/workspace/250106%20AGENTS/debug-mcp-server/dist/proxy/dap-proxy-worker.js:36:21)
at handleInitCommand (file:///C:/Users/user/workspace/250106%20AGENTS/debug-mcp-server/dist/proxy/dap-proxy-worker.js:167:18)
```

**Root Cause Analysis**:

The error occurs at line 167 of `dap-proxy-worker.js` in the `handleInitCommand` function. The proxy successfully:
- Established IPC communication
- Received the initialization message
- Parsed the message correctly
- Began processing the init command

But then exits with code 1, suggesting an unhandled exception or error condition during initialization processing. The issue is specifically in the `handleInitCommand` function after receiving a valid initialization message.

**Potential Causes**:
1. **CodeLLDB adapter executable issue**: The codelldb.exe at the specified path may not exist, not be executable, or fail to start
2. **Port binding issue**: Port 57227 may not be available or there's a firewall issue
3. **Environment variable issue**: Some required environment variable may be missing or incorrect
4. **Unhandled exception**: An error condition in handleInitCommand that's not being caught
5. **Timeout**: The adapter may be taking too long to initialize
6. **CodeLLDB compatibility**: The CodeLLDB version may not be compatible with the Rust executable format or Windows environment

**Files That Would Need Investigation**:
- `dist/proxy/dap-proxy-worker.js` (line 167)
- `packages/adapter-rust/src/rust-debug-adapter.ts` (adapter initialization logic)
- `packages/adapter-rust/vendor/codelldb/win32-x64/adapter/codelldb.exe` (verify existence and permissions)

---

## Issues Summary

### Critical Issues (Blocking)
1. **Proxy Exit During Initialization** (CRITICAL)
   - Location: `dap-proxy-worker.js:167` in `handleInitCommand`
   - Impact: Cannot start any Rust debugging session
   - Exit code: 1
   - Stage: After receiving init command, before adapter connection established

### Major Issues
2. **Relative Path Breakpoints Not Supported**
   - Breakpoint setting requires absolute paths
   - Relative paths fail with "file not found" error
   - Impact: Less convenient API usage

### Testing Stopped
Per instructions, testing was stopped after `start_debugging` failed. The following tests were not performed:
- Step through hello_world code
- Variable inspection
- Stack trace examination  
- Continue execution
- async_example testing
- Async task debugging

## Recommendations

1. **Immediate Priority**: Fix proxy initialization crash in `handleInitCommand`
   - Add better error handling and logging
   - Verify CodeLLDB executable exists and is accessible
   - Test port availability before attempting to bind
   - Add timeout handling

2. **Add Diagnostic Logging**: 
   - Log the exact error that causes exit code 1
   - Include CodeLLDB adapter startup logs
   - Capture stderr from the adapter process

3. **Improve Path Handling**:
   - Support relative paths for breakpoints
   - Convert relative to absolute paths internally
   - Document path requirements in API

4. **Add Validation**:
   - Validate scriptPath exists before starting debugger
   - Check CodeLLDB executable exists and is executable
   - Verify port availability

5. **Better Error Messages**:
   - Return the actual error that caused the exit
   - Include suggestions for common issues
   - Add troubleshooting steps to error messages

## Test Files Examined

### hello_world/src/main.rs
Simple Rust program demonstrating:
- Variable inspection (primitives, strings, vectors)
- Function calls and parameter inspection
- Control flow (if statements, loops)
- String manipulation

**Key Test Points**:
- Line 13: Variable declaration `let name = "Rust";`
- Line 18: Function call `calculate_sum(5, 10)`
- Line 40: Function with parameters for inspection

### async_example/src/main.rs  
Async Rust with Tokio demonstrating:
- Async/await functions
- Concurrent tasks with `tokio::spawn`
- tokio::join! for multiple tasks
- Async loops

**Key Test Points**:
- Line 15: Async function call `fetch_data(1).await`
- Line 18-20: Multiple concurrent spawned tasks
- Line 38: Breakpoint location in async function

## Conclusion

The MCP debugger for Rust fails at the critical `start_debugging` step due to a proxy initialization error in `handleInitCommand`. While session creation and breakpoint setting work (with absolute paths), the core debugging functionality is blocked by this initialization failure. The exact cause needs investigation of the proxy worker code and CodeLLDB adapter integration, but the error occurs after IPC communication is established and during the processing of the initialization command.

No further testing was performed per instructions to stop if `start_debugging` fails.
