# ChatDBG

by [Emery Berger](https://emeryberger.com)

ChatDBG is an experimental debugger for Python *and* native C/C++ code that integrates large language models into a standard debugger (`pdb`, `lldb`, and `gdb`) to help debug your code. With ChatDBG, you can ask your debugger "why" your program failed, and it will provide a suggested fix.

As far as we are aware, ChatDBG is the *first* debugger to automatically perform root cause analysis and to provide suggested fixes. This is an alpha release; we greatly welcome feedback and suggestions!

[![PyPI Latest Release](https://img.shields.io/pypi/v/chatdbg.svg)](https://pypi.org/project/chatdbg/)[![Downloads](https://static.pepy.tech/badge/chatdbg)](https://pepy.tech/project/chatdbg) [![Downloads](https://static.pepy.tech/badge/chatdbg/month)](https://pepy.tech/project/chatdbg) ![Python versions](https://img.shields.io/pypi/pyversions/chatdbg.svg?style=flat-square)


## Installation

*NOTE*: To use ChatDBG, you must first set up an OpenAI API key. If you
already have an API key, you can set it as an environment variable
called `OPENAI_API_KEY`. If you do not have one yet,
you can get a key here: https://platform.openai.com/account/api-keys

```bash
export OPENAI_API_KEY=<your-api-key>
```

Install ChatDBG using `pip` (you need to do this whether you are debugging Python, C, or C++ code):

```bash
python3 -m pip install chatdbg
```

If you are using ChatDBG to debug Python programs, you are done. If you want to use ChatDBG to debug native code with `gdb` or `lldb`, follow the installation instructions below.

### Installing as an <TT>lldb</TT> extension

<details>
<summary>
<B><TT>lldb</TT> installation instructions</B>
</summary>

Install ChatDBG into the `lldb` debugger by running the following command:

#### Linux

```bash
python3 -m pip install ChatDBG
python3 -c 'import chatdbg; print(f"command script import {chatdbg.__path__[0]}/chatdbg_lldb.py")' >> ~/.lldbinit
```

#### Mac

```bash
xcrun python3 -m pip install ChatDBG
xcrun python3 -c 'import chatdbg; print(f"command script import {chatdbg.__path__[0]}/chatdbg_lldb.py")' >> ~/.lldbinit
```

This will install ChatDBG as an LLVM extension.
</details>

### Installing as a <TT>gdb</TT> extension

<details>
<summary>
<B><TT>gdb</TT> installation instructions</B>
</summary>

Install ChatDBG into the `gdb` debugger by running the following command:

```bash
python3 -m pip install ChatDBG
python3 -c 'import chatdbg; print(f"source {chatdbg.__path__[0]}/chatdbg_gdb.py")' >> ~/.gdbinit
```

This will install ChatDBG as a GDB extension.
</details>

## Usage

### Debugging Python

To use ChatDBG to debug Python programs, simply run your Python script with the `-m` flag:

```bash
python3 -m chatdbg -c continue yourscript.py
```

or just

```bash
chatdbg -c continue yourscript.py
```

ChatDBG is an extension of the standard Python debugger `pdb`. Like
`pdb`, when your script encounters an uncaught exception, ChatDBG will
enter post mortem debugging mode.

Unlike other debuggers, you can then use the `why` command to ask
ChatDBG why your program failed and get a suggested fix.

### Debugging native code (C, C++, or Rust with <TT>lldb</TT> / <TT>gdb</TT>)

To use ChatDBG with `lldb` or `gdb`, just run native code (compiled with `-g` for debugging symbols) with your choice of debugger; when it crashes, ask `why`. This also works for post mortem debugging (when you load a core with the `-c` option).

<details>
<summary>
<B>Debugging Rust programs</B>
</summary>

To use ChatDBG with Rust, you need to do two steps: modify your
`Cargo.toml` file and add one line to your source program.

1. Add this to your `Cargo.toml` file:

```toml
[dependencies]
chatdbg = "0.1.2"

[profile.dev]
panic = "abort"

[profile.release]
panic = "abort"
```

2. In your program, run `chatdbg::chatdbg()` as early as possible.

```rust
use chatdbg;

fn main() {
   chatdbg::chatdbg();
   // Insert the above line as early as possible in your main function
```

Now you can run your Rust code with `lldb` (`gdb` is not yet supported).

</details>

### Examples

<details>
<summary>
<B>ChatDBG example in <TT>lldb</TT></B>
</summary>

```gdb
(ChatDBG lldb) run
Process 85494 launched: '/Users/emery/git/ChatDBG/test/a.out' (arm64)
TEST 1
TEST -422761288
TEST 0
TEST 0
TEST 0
TEST 0
TEST 0
TEST 0
Process 85494 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x100056200)
    frame #0: 0x0000000100002f64 a.out`foo(n=8, b=1) at test.cpp:7:22
   4     int x[] = { 1, 2, 3, 4, 5 };
   5     
   6     void foo(int n, float b) {
-> 7       cout << "TEST " << x[n * 10000] << endl;
   8     }
   9     
   10    int main()
Target 0: (a.out) stopped.
```

Ask `why` to have ChatDBG provide a helpful explanation why this program failed, and suggest a fix:


```gdb
(ChatDBG lldb) why
The root cause of this error is accessing an index of the array `x`
that is out of bounds. In `foo()`, the index is calculated as `n *
10000`, which can be much larger than the size of the array `x` (which
is only 5 elements). In the given trace, the program is trying to
access the memory address `0x100056200`, which is outside of the range
of allocated memory for the array `x`.

To fix this error, we need to ensure that the index is within the
bounds of the array. One way to do this is to check the value of `n`
before calculating the index, and ensure that it is less than the size
of the array divided by the size of the element. For example, we can
modify `foo()` as follows:

    ```
    void foo(int n, float b) {
      if (n < 0 || n >= sizeof(x)/sizeof(x[0])) {
        cout << "ERROR: Invalid index" << endl;
        return;
      }
      cout << "TEST " << x[n] << endl;
    }
    ```

This code checks if `n` is within the valid range, and prints an error
message if it is not. If `n` is within the range, the function prints
the value of the element at index `n` of `x`. With this modification,
the program will avoid accessing memory outside the bounds of the
array, and will print the expected output for valid indices.
```
</details>

<details>
<summary>
<B>ChatDBG example in Python (<TT>pdb</TT>)</B>
</summary>

```python
Traceback (most recent call last):
  File "yourscript.py", line 9, in <module>
    print(tryme(100))
  File "yourscript.py", line 4, in tryme
    if x / i > 2:
ZeroDivisionError: division by zero
Uncaught exception. Entering post mortem debugging
Running 'cont' or 'step' will restart the program
> yourscript.py(4)tryme()
-> if x / i > 2:
```

Ask `why` to have ChatDBG provide a helpful explanation why this program failed, and suggest a fix:

```python
(ChatDBG Pdb) why
The root cause of the error is that the code is attempting to
divide by zero in the line "if x / i > 2". As i ranges from 0 to 99,
it will eventually reach the value of 0, causing a ZeroDivisionError.

A possible fix for this would be to add a check for i being equal to
zero before performing the division. This could be done by adding an
additional conditional statement, such as "if i == 0: continue", to
skip over the iteration when i is zero. The updated code would look
like this:

def tryme(x):
    count = 0
    for i in range(100):
        if i == 0:
            continue
        if x / i > 2:
            count += 1
    return count

if __name__ == '__main__':
    print(tryme(100))
```

</details>

