BoundaryML/baml · error

Enum with name {name} does not exist

Error message

Enum with name {name} does not exist

What it means

TypeBuilder::r#enum looks up an existing enum builder by name. If the enum exists in the runtime IR but was not registered on this TypeBuilder (maybe_get_enum returns None), or does not exist at all, the lookup bails with this error.

Source

Thrown at engine/language_client_cffi/src/raw_ptr_wrapper/type_builder/objects.rs:123

    }

    pub fn r#enum(&self, rt: &BamlRuntime, name: &str) -> anyhow::Result<EnumBuilder> {
        match rt.ir.find_enum(name) {
            Ok(enm) => {
                let _ = self.type_builder.upsert_enum(name);
                let builder = EnumBuilder::new(self.type_builder.clone(), name.to_string());
                if !enm.item.attributes.dynamic() {
                    return Ok(builder.mode(NodeRW::ReadOnly));
                }
                Ok(builder.mode(NodeRW::ReadWrite))
            }
            Err(_) => match self.type_builder.maybe_get_enum(name) {
                Some(_) => Ok(EnumBuilder::new(
                    self.type_builder.clone(),
                    name.to_string(),
                )),
                None => {
                    anyhow::bail!("Enum with name {name} does not exist");
                }
            },
        }
    }

    pub fn add_baml(&self, baml: &str, rt: &BamlRuntime) -> anyhow::Result<()> {
        self.type_builder.add_baml(baml, rt)
    }

    pub fn list_enums(&self, rt: &BamlRuntime) -> Vec<EnumBuilder> {
        let ir = &rt.ir;
        let enums = ir.walk_enums();
        enums
            .map(|enm| enm.name().to_string())
            .chain(self.type_builder.list_enums())
            .collect::<indexmap::IndexSet<_>>()
            .into_iter()
            .map(|name| EnumBuilder::new(self.type_builder.clone(), name))

View on GitHub (pinned to bd85ce9dee)

Solutions

1. Add the enum first with tb.add_enum(rt, name) before lookup
2. Verify the enum name matches the BAML declaration exactly
3. Use the same TypeBuilder instance for add and lookup

Example fix

// before
let eb = tb.r#enum(rt, "Colr")?; // typo -> does not exist
// after
let eb = match tb.r#enum(rt, "Color") {
    Ok(eb) => eb,
    Err(_) => tb.add_enum(rt, "Color")?,
};

# verify name against known enums
assert "Color" in known_enum_names, f"enum 'Color' not defined"

try:
    eb = tb.enum(name)
except Exception as e:
    if "does not exist" in str(e):
        eb = tb.add_enum(rt, name)
    else:
        raise

When it happens

Trigger: Calling tb.r#enum(rt, "Name") for an enum name that is neither in the runtime IR nor registered on this TypeBuilder (typo or never added via add_enum).

Common situations: Typo in enum name; calling .r#enum() before add_enum(); using a different TypeBuilder instance than the one the enum was added to.

Understand the failure class

Background: "Not found" and "does not exist" errors: why "Task not found", "No such folder", and "Can't find" fire when a lookup comes back empty — this error's family across 14 libraries.

Related errors

• Enum {} not found
• Enum with name {name} already exists
• Class with name {name} does not exist
• Enum '{0}' not found
• Enum {name} not found

AI-assisted analysis of BoundaryML/baml@bd85ce9dee (2026-09-12). Data as JSON: /api/errors/05be22691c2e9973. Report an issue: GitHub.