Comfy-Org/ComfyUI · error · ValueError

Invalid {cls.name} string: '{value}'. Valid values are:

Error message

Invalid {cls.__name__} string: '{value}'. Valid values are: {valid_values}

What it means

Raised by StringConvertibleEnum when a string value cannot be matched (case-insensitively) to any member value of the enum. The message lists all valid string values, including 'none' for members whose value is None. This is the enum's input-validation error for bad string config values.

Source

Thrown at comfy/ldm/lightricks/vae/causal_audio_autoencoder.py:67

            # Try to match against enum values
            for member in cls:
                # Handle members with None values
                if member.value is None:
                    if value_lower == "none":
                        return member
                # Handle members with string values
                elif isinstance(member.value, str) and member.value.lower() == value_lower:
                    return member

            # Build helpful error message with valid values
            valid_values = []
            for member in cls:
                if member.value is None:
                    valid_values.append("none")
                elif isinstance(member.value, str):
                    valid_values.append(member.value)

            raise ValueError(f"Invalid {cls.__name__} string: '{value}'. " f"Valid values are: {valid_values}")

        raise ValueError(
            f"Cannot convert type {type(value).__name__} to {cls.__name__} enum. "
            f"Expected string, None, or {cls.__name__} instance."
        )


class AttentionType(StringConvertibleEnum):
    """Enum for specifying the attention mechanism type."""

    VANILLA = "vanilla"
    LINEAR = "linear"
    NONE = "none"


class CausalityAxis(StringConvertibleEnum):
    """Enum for specifying the causality axis in causal convolutions."""

View on GitHub (pinned to 1c6d8d45b3)

Solutions

Use one of the valid values printed in the error message (e.g. 'vanilla', 'linear', 'none' for AttentionType)
Check spelling and hyphenation against the enum definition in causal_audio_autoencoder.py
Pass the enum member itself (AttentionType.VANILLA) instead of a string to avoid conversion entirely

Example fix

# before
block = make_attention(in_channels, attn_type="vanila")

# after
block = make_attention(in_channels, attn_type="vanilla")

Defensive patterns

Strategy: validation

Validate before calling

VALID_ATTN = {m.value for m in AttentionType}
if isinstance(attn_type, str) and attn_type.lower() not in VALID_ATTN:
    raise ValueError(f"bad attention type {attn_type!r}; valid: {sorted(VALID_ATTN)}")
attn_type = AttentionType(attn_type)

Type guard

def is_valid_enum_string(cls, s: str) -> bool:
    return any(isinstance(m.value, str) and m.value.lower() == s.lower() for m in cls) or (s.lower() == "none" and hasattr(cls, "NONE"))

Prevention

Validate config strings against the enum before constructing modules
Log the valid-values list (it is in the error message) when surfacing config errors to users
Generate config UIs from the enum members instead of free-text fields

When it happens

Trigger: Calling a constructor that converts a string to AttentionType/CausalityAxis with a misspelled or unsupported value, e.g. CausalityAxis('widht'), AttentionType('linear-attention'), or AttentionType('off') instead of AttentionType.NONE.

Common situations: Typos in checkpoint-derived or user-supplied config dicts; renaming mismatches when porting configs from the upstream lightricks repository (e.g. 'vanilla' vs 'standard'); case variants like 'Vanilla' work but 'n/a' do not.

Related errors

AI-assisted analysis of Comfy-Org/ComfyUI@1c6d8d45b3 (2026-08-14). Data as JSON: /api/errors/e7ea6c0333dc8043. Report an issue: GitHub.