dbt-labs/dbt-core · error · syn::Error

`crate` set multiple times.

Error message

`crate` set multiple times.

What it means

The `crate` attribute option overrides which crate path the macro-generated code refers to (useful when tokio is re-exported under a different name). It may be specified only once; set_crate_name returns a syn::Error if crate_name is already Some. The error message says `crate` even though the field is crate_name.

Source

Thrown at crates/dbt-runtime-macros/src/entry.rs:170

            return Err(syn::Error::new(span, "`worker_threads` may not be 0."));
        }
        self.worker_threads = Some((worker_threads, span));
        Ok(())
    }

    fn set_start_paused(&mut self, start_paused: syn::Lit, span: Span) -> Result<(), syn::Error> {
        if self.start_paused.is_some() {
            return Err(syn::Error::new(span, "`start_paused` set multiple times."));
        }

        let start_paused = parse_bool(start_paused, span, "start_paused")?;
        self.start_paused = Some((start_paused, span));
        Ok(())
    }

    fn set_crate_name(&mut self, name: syn::Lit, span: Span) -> Result<(), syn::Error> {
        if self.crate_name.is_some() {
            return Err(syn::Error::new(span, "`crate` set multiple times."));
        }
        let name_path = parse_path(name, span, "crate")?;
        self.crate_name = Some(name_path);
        Ok(())
    }

    fn set_unhandled_panic(
        &mut self,
        unhandled_panic: syn::Lit,
        span: Span,
    ) -> Result<(), syn::Error> {
        if self.unhandled_panic.is_some() {
            return Err(syn::Error::new(
                span,
                "`unhandled_panic` set multiple times.",
            ));
        }

View on GitHub (pinned to 0267ce9170)

Solutions

1. Specify the `crate = "path"` key exactly once with the correct re-export path
2. Remove the duplicate key, keeping the path that actually resolves tokio
3. If two crates need different paths, use separate entry functions

Example fix

// before
#[tokio::main(crate = "tokio", crate = "my_app::tokio")]
async fn main() {}

// after
#[tokio::main(crate = "my_app::tokio")]
async fn main() {}

fn check_crate_arg_once(attr_src: &str) -> Result<(), String> {
    let n = attr_src.matches("crate =").count();
    if n <= 1 { Ok(()) } else { Err("duplicate `crate` attribute arg".into()) }
}

When it happens

Trigger: #[tokio::main(crate = "tokio", crate = "my_tokio")] — passing the `crate` key twice in one attribute.

Common situations: Re-export setups where a wrapper crate re-exports tokio and both the wrapper and the developer add a `crate` argument; mechanical attribute merging.

Understand the failure class

Background: Conflicting config options: "cannot be used together" — configuration validation errors across open-source libraries — this error's family across 162 libraries.

Related errors

• `worker_threads` set multiple times.
• `start_paused` set multiple times.
• `unhandled_panic` set multiple times.
• No such runtime flavor `{s}`. The runtime flavors are `curre
• `worker_threads` may not be 0.

AI-assisted analysis of dbt-labs/dbt-core@0267ce9170 (2026-09-07). Data as JSON: /api/errors/104e7a3670fb9212. Report an issue: GitHub.