What happened?

Issue: COPRO eval_kwargs Parameter Not Actually Optional

Problem Description

The COPRO optimizer documentation at https://dspy.ai/api/optimizers/COPRO/ indicates that eval_kwargs is an optional parameter, but in practice it is required. This creates a discrepancy between the documented API and the actual implementation.

Current Behavior

• eval_kwargs must be provided or the code will fail
• Workaround: Pass an empty dictionary ({})

Proposed Solutions

Option 1: Update Implementation (Recommended)

Make eval_kwargs truly optional by setting a default value:

def __init__(self, ..., eval_kwargs=None):
    self.eval_kwargs = eval_kwargs or {}

Steps to reproduce

A simple example with prompt auto-tuning, using COPRO should be enough.

DSPy version

3.0.4