BoundaryML/baml · error · ConvertError

Unknown media kind

Error message

Unknown media kind

What it means

`ConvertError::UnknownMediaKind` is raised by the sap_model type converter when it encounters a media kind it does not recognize. During conversion of type expressions containing media (e.g. image/audio/video types), an unrecognized kind string has no mapping in the converter.

Solutions

1. Check the media kind spelling in the source against the kinds supported by your bex_sap version.
2. Upgrade bex_sap/baml_language so the converter recognizes the new media kind.
3. Add a match arm for the new media kind in the converter if you maintain the crate.
4. Fall back to a generic/string type if the media kind is not essential.

Example fix

// before
match kind {
    MediaKind::Image => ...,
    MediaKind::Audio => ...,
}
// after
match kind {
    MediaKind::Image => ...,
    MediaKind::Audio => ...,
    MediaKind::Video => ..., // newly supported
    other => return Err(ConvertError::UnknownMediaKind),
}

const SUPPORTED_MEDIA_KINDS: &[&str] = &["image", "audio", "video"];
fn media_kind_supported(k: &str) -> bool { SUPPORTED_MEDIA_KINDS.contains(&k) }
// check before conversion

fn as_known_media_kind(k: &MediaKind) -> Option<&MediaKind> {
    matches!(k, MediaKind::Image | MediaKind::Audio | MediaKind::Video).then_some(k)
}

match convert(ty) {
    Ok(m) => m,
    Err(ConvertError::UnknownMediaKind) => { eprintln!("media kind unsupported by this bex_sap version"); fallback_to_string_type(ty) }
    Err(e) => return Err(e.into()),
}

When it happens

Trigger: Converting a SapTy containing a media variant whose kind (image, audio, etc.) is not one of the kinds `convert.rs` knows — e.g. a newly added media kind in the grammar not yet handled in the converter match.

Common situations: Using a new/experimental media type in BLP source with an older bex_sap version; a typo in a media kind name; grammar and converter versions drifting apart.

Related errors

• BamlSerde cannot be derived for enums, use…
• capture loss omitted kind
• capture loss omitted reason
• Could not unify Enum
• Enum does not exist

AI-assisted analysis of BoundaryML/baml@bd85ce9dee (2026-09-12). Data as JSON: /api/errors/f595decff2a775fb. Report an issue: GitHub.

Appendix: source

Thrown at baml_language/crates/bex_sap/src/sap_model/convert.rs:26

    sync::Arc,
};
use ::sys_types::{ClassDefinition, DefKey, EnumDefinition, SapTy};
use indexmap::IndexMap;

use crate::sap_model::{
    self, AnnotatedEnumVariant, AnnotatedField, AnnotatedTy, ArrayTy, AttrLiteral, BigintLiteralTy,
    BigintTy, BoolLiteralTy, BoolTy, ClassTy, EnumTy, EnumVariantTy, FloatTy, IntLiteralTy, IntTy,
    MapTy, MediaTy, NullTy, StringLiteralTy, StringTy, TyResolved, TyWithMeta, TypeAnnotations,
    TypeRefDb, UnionTy,
};

impl crate::sap_model::TypeIdent for DefKey {}

#[derive(thiserror::Error, Debug)]
pub enum ConvertError {
    #[error("Failed to parse float: {0}")]
    ParseFloat(#[from] std::num::ParseFloatError),
    #[error("Unknown media kind")]
    UnknownMediaKind,
    #[error("Float literals cannot be parsed")]
    FloatLiteral,
    #[error("Non-parsable type: {0:?}")]
    NonParsableType(Box<SapTy>),
    #[error("Unknown class: {0}")]
    UnknownClass(DefKey),
    #[error("Unknown enum: {0}")]
    UnknownEnum(DefKey),
    #[error("Unknown type alias: {0}")]
    UnknownTypeAlias(DefKey),
    #[error("Unknown name (could not determine if it was a class, enum, or type alias): {0}")]
    UnknownName(DefKey),
    #[error("Could not add a type to the database as the name `{0}` is already present")]
    AlreadyPresent(DefKey),
    #[error("Recursion depth exceeded for {0}")]
    RecursionDepthExceeded(&'static str),
    #[error("Unions must be flattened")]

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