# Debugger (Beta)

Zed uses the Debug Adapter Protocol (DAP) to provide debugging functionality across multiple programming languages.
DAP is a standardized protocol that defines how debuggers, editors, and IDEs communicate with each other.
It allows Zed to support various debuggers without needing to implement language-specific debugging logic.
This protocol enables features like setting breakpoints, stepping through code, inspecting variables,
and more, in a consistent manner across different programming languages and runtime environments.

## Supported Debug Adapters

Zed supports a variety of debug adapters for different programming languages:

- JavaScript (node): Enables debugging of Node.js applications, including setting breakpoints, stepping through code, and inspecting variables in JavaScript.

- Python (debugpy): Provides debugging capabilities for Python applications, supporting features like remote debugging, multi-threaded debugging, and Django/Flask application debugging.

- LLDB: A powerful debugger for C, C++, Objective-C, and Swift, offering low-level debugging features and support for Apple platforms.

- GDB: The GNU Debugger, which supports debugging for multiple programming languages including C, C++, Go, and Rust, across various platforms.

- Go (dlv): Delve, a debugger for the Go programming language, offering both local and remote debugging capabilities with full support for Go's runtime and standard library.

- PHP (xdebug): Provides debugging and profiling capabilities for PHP applications, including remote debugging and code coverage analysis.

These adapters enable Zed to provide a consistent debugging experience across multiple languages while leveraging the specific features and capabilities of each debugger.

Additionally, Ruby support (via rdbg) is being actively worked on.

## Getting Started

For basic debugging, you can set up a new configuration by opening the `New Session Modal` either via the `debugger: start` (default: f4) or by clicking the plus icon at the top right of the debug panel.

For more advanced use cases, you can create debug configurations by directly editing the `.zed/debug.json` file in your project root directory.

You can then use the `New Session Modal` to select a configuration and start debugging.

### Launching & Attaching

Zed debugger offers two ways to debug your program; you can either _launch_ a new instance of your program or _attach_ to an existing process.
Which one you choose depends on what you are trying to achieve.

When launching a new instance, Zed (and the underlying debug adapter) can often do a better job at picking up the debug information compared to attaching to an existing process, since it controls the lifetime of a whole program. Running unit tests or a debug build of your application is a good use case for launching.

Compared to launching, attaching to an existing process might seem inferior, but that's far from truth; there are cases where you cannot afford to restart your program, because e.g. the bug is not reproducible outside of a production environment or some other circumstances.

## Configuration

While configuration fields are debug adapter-dependent, most adapters support the following fields:

```json
[
  {
    // The label for the debug configuration and used to identify the debug session inside the debug panel & new session modal
    "label": "Example Start debugger config",
    // The debug adapter that Zed should use to debug the program
    "adapter": "Example adapter name",
    // Request:
    //  - launch: Zed will launch the program if specified or shows a debug terminal with the right configuration
    //  - attach: Zed will attach to a running program to debug it or when the process_id is not specified we will show a process picker (only supported for node currently)
    "request": "launch",
    // program: The program that you want to debug
    // This field supports path resolution with ~ or . symbols
    "program": "path_to_program",