Inconsistent Input Handling in Forward Methods

[techexport]

Description

The model's forward methods have inconsistent parameter handling across different implementations. In particular, ControlPixArtMSHalf_RelaCtrl implements a forward method that shadows the one from the parent class, but without proper handling of the c parameter when it's None.

Steps to Reproduce

In diffusion/model/nets/pixart_relactrl_v1.py, the forward method in ControlPixArtHalf_RelaCtrl handles conditioning properly:

def forward_c(self, c):
    # Properly process c if it's not None
    return self.x_embedder(c) + pos_embed if c is not None else c

While in ControlPixArtMSHalf_RelaCtrl, it seems to directly call forward_c(c) without checking if c is None first, which could lead to errors.

Proposed Solution

Ensure consistent parameter handling across all forward methods. Specifically:

1. Make sure all inherited methods properly handle the case where c is None
2. Add proper error handling and validation for input parameters
3. Consider creating a standardized interface for all forward methods to ensure consistency

[MaAo]

Thank you for your attention. We will fix it during the next code PR.