swc-project/swc · error

`deno bundle` failed with status code {}

Error message

`deno bundle` failed with status code {}

What it means

dbg-swc's bundle helper shells out to the deno CLI ('deno bundle <entry_url>'), inheriting stderr so deno's own error output reaches the terminal, and bails with the child's status code when it exits non-zero. The failure comes from deno, not from SWC: module download failures, an unreachable or mistyped entry URL, compile errors in the dependency graph, or a deno binary that no longer supports the bundle subcommand (it was removed in Deno 2).

Source

Thrown at crates/dbg-swc/src/bundle.rs:22

};

use anyhow::{bail, Context, Result};
use swc_common::{FileName, SourceMap};

use crate::util::{parse_js, wrap_task, ModuleRecord};

pub fn bundle(cm: Arc<SourceMap>, entry_url: &str) -> Result<ModuleRecord> {
    wrap_task(|| {
        let mut cmd = Command::new("deno");
        cmd.arg("bundle");
        cmd.arg(entry_url);

        cmd.stderr(Stdio::inherit());

        let output = cmd.output().context("failed to invoke `deno bundle`")?;

        if !output.status.success() {
            bail!("`deno bundle` failed with status code {}", output.status);
        }

        let code =
            String::from_utf8(output.stdout).context("deno bundle emitted non-utf8 output")?;

        let fm = cm.new_source_file(FileName::Anon.into(), code);
        parse_js(fm).context("failed to parse js filed emitted by `deno bundle`")
    })
    .with_context(|| format!("failed to bundle `{entry_url}`"))
}

View on GitHub (pinned to 5176682b65)

Solutions

  1. Run 'deno bundle <entry_url>' manually in the same shell - deno's stderr shows the true reason
  2. Check 'deno --version': 'deno bundle' was removed in Deno 2; pin Deno 1.x for this helper
  3. Ensure network/proxy access and DENO_AUTH_TOKENS for private modules, or vendor dependencies locally
  4. Verify the entry URL resolves (curl it) before invoking dbg-swc

Example fix

# before: system deno is 2.x, `deno bundle` is gone
$ deno --version
deno 2.0.0

# after: pin a 1.x deno for this workflow
$ asdf install deno 1.46.3
$ asdf local deno 1.46.3
$ deno bundle ./entry.ts   # works, dbg-swc bundle proceeds
Defensive patterns

Strategy: retry

Validate before calling

use std::process::Command;

fn deno_available() -> bool {
    Command::new("deno")
        .arg("--version")
        .output()
        .map(|o| o.status.success())
        .unwrap_or(false)
}

fn entry_reachable(url: &str) -> bool {
    // cheap check before shelling out
    url::Url::parse(url).is_ok()
}

Try / catch

fn bundle_retry(cm: Arc<SourceMap>, url: &str) -> Result<ModuleRecord> {
    let mut last = None;
    for attempt in 0..3 {
        match bundle(cm.clone(), url) {
            Ok(r) => return Ok(r),
            Err(e) => {
                let msg = format!("{e:#}");
                if msg.contains("failed to invoke") || msg.contains("removed") {
                    return Err(e); // binary missing / unsupported subcommand: do not retry
                }
                eprintln!("deno bundle attempt {} failed: {}", attempt + 1, msg);
                last = Some(e);
            }
        }
    }
    Err(last.expect("at least one attempt"))
}

Prevention

When it happens

Trigger: Running the dbg-swc bundle command for an entry URL deno cannot fetch or compile; the message shows the raw exit status (deno uses 101 for uncaught errors, 1 for general failure).

Common situations: Offline or proxied sandboxes where deno cannot download remote modules; environments that upgraded to Deno 2.x where 'deno bundle' no longer exists; remote specifiers behind auth (missing DENO_AUTH_TOKENS); typos in the entry URL.

Related errors

AI-assisted analysis of swc-project/swc@5176682b65 (2026-08-17). Data as JSON: /api/errors/161e62a80b59b37f. Report an issue: GitHub.