openpilot_comma/docs/DEBUGGING_SAFETY.md

# Debugging Panda Safety with Replay Drive + LLDB

## Debugging Workflow

1. **Start the debugger in VS Code**

    * Select **Replay drive + Safety LLDB**.
    * Enter the route or segment when prompted.

2. **Attach LLDB**

    * When prompted, pick the running **`replay_drive` process**.
    * ⚠️ Attach quickly, or `replay_drive` will start consuming messages.

> [!TIP]
> Add a Python breakpoint at the start of `replay_drive.py` to pause execution and give yourself time to attach LLDB.

3. **Set breakpoints in VS Code**
   Breakpoints can be set directly in `libsafety.c` (or any C file).
   No extra LLDB commands are required — just place breakpoints in the editor.

4. **Resume execution**
   Once attached, you can step through both Python and C safety code as CAN logs are replayed.

> [!NOTE]
> * Use short routes for quicker iteration.
> * Pause `replay_drive` early to avoid wasting log messages.

## Video

View a demo of this workflow on the PR that added it: https://github.com/commaai/openpilot/pull/36055#issue-3352911578