Fix mutable default list argument in config classes

[hobostay]

Summary

• Fix mutable default argument encoder_ratios=[8,5,5,4,2,2] in VibeVoiceAcousticTokenizerConfig and VibeVoiceSemanticTokenizerConfig
• Python evaluates default arguments once at class definition time, so all instances share the same list object
• Mutating the list on one instance (e.g., via .append(), .sort()) would silently corrupt all other instances
• Also use list(encoder_ratios) when assigning decoder_ratios to avoid shared references

Details

Affected file: vibevoice/modular/configuration_vibevoice.py (lines 55, 118)

Changed encoder_ratios: Optional[List[int]] = [8,5,5,4,2,2] to encoder_ratios: Optional[List[int]] = None with if encoder_ratios is None: encoder_ratios = [8, 5, 5, 4, 2, 2] inside the method body. This is a well-known Python pitfall.

Test plan

• Verify configs can still be instantiated without arguments (default values preserved)
• Verify mutations on one config instance don't affect others

🤖 Generated with Claude Code

[rickthomasjr]

Review: Approve — fix mutable default list argument

Correctness: Default encoder_ratios: Optional[List[int]] = [8,5,5,4,2,2] is a classic Python mutable default argument bug. All instances of the class would share the same list object, leading to cross-talk between configs.

Fix is standard: Switch to None default and assign in-body. Clean and idiomatic.

Verdict: Approve. Correct fix for a well-known Python gotcha.