How to Contribute Code

General

For general improvements/bug fixes just make a pull request.

• Before doing anything, make sure your change is wanted. Make sure there's an open Feature Request or Bug Report on the issues page.
• Try to make a single pull request for each change to make reviewing easier, as opposed to large/bulky PRs.
  • Especially first time contributors should focus on very simple and small tasks, and take on tougher ones after you've had a PR or two successfully pulled.
• avoid adding "sensitive" code, eg eval(...), unless absolutely unavoidable

Special Cases

Adding support for new model architectures

Checklist of requirements for a PR that adds support for a new model architecture:

• Have a minimal implementation of the model code that only depends on pytorch under a license compatible with the GPL license that ComfyUI uses.
• Provide a reference image with sampling settings/seed/etc. so that we can make sure the ComfyUI implementation matches the reference one.
• Replace all attention functions with the comfyui optimized_attention attention function.
• If you are the part of the team that authored the model architecture itself:
  • Please release your primary models in .safetensors file format, not legacy .ckpt pickle files.
  • Please include proper identifying metadata in the header of the file.

Example of the SDPA implementation:

def optimized_attention(q, k, v, heads, mask=None, attn_precision=None, skip_reshape=False):
    if skip_reshape:
        b, _, _, dim_head = q.shape
    else:
        b, _, dim_head = q.shape
        dim_head //= heads
        q, k, v = map(
            lambda t: t.view(b, -1, heads, dim_head).transpose(1, 2),
            (q, k, v),
        )

    out = torch.nn.functional.scaled_dot_product_attention(q, k, v, attn_mask=mask, dropout_p=0.0, is_causal=False)
    out = (
        out.transpose(1, 2).reshape(b, -1, heads * dim_head)
    )
    return out

Examples in the Code:

Audio

SDXL Cascade

mmdit

After that you can just ping comfyanonymous on matrix or @comfyanon on discord and he will take a look.