swc-project/swc · error · anyhow::Error

failed to deserialize .swcrc (json) file: {msg}: {line}:{col

Error message

failed to deserialize .swcrc (json) file: {msg}: {line}:{column}

What it means

parse_swcrc could not deserialize the .swcrc file as JSON; convert_json_err classifies the serde_json failure (io, syntax, data, eof) and embeds line:column. Raised while loading configuration, before any file is compiled — the config file itself is broken.

Source

Thrown at crates/swc/src/lib.rs:1429

#[cfg_attr(debug_assertions, tracing::instrument(skip_all))]
fn load_swcrc(path: &Path) -> Result<Rc, Error> {
    let content = read_to_string(path).context("failed to read config (.swcrc) file")?;

    parse_swcrc(&content)
}

fn parse_swcrc(s: &str) -> Result<Rc, Error> {
    fn convert_json_err(e: serde_json::Error) -> Error {
        let line = e.line();
        let column = e.column();

        let msg = match e.classify() {
            Category::Io => "io error",
            Category::Syntax => "syntax error",
            Category::Data => "unmatched data",
            Category::Eof => "unexpected eof",
        };
        Error::new(e).context(format!(
            "failed to deserialize .swcrc (json) file: {msg}: {line}:{column}"
        ))
    }

    let v = parse_to_serde_value(
        s.trim_start_matches('\u{feff}'),
        &ParseOptions {
            allow_comments: true,
            allow_trailing_commas: true,
            allow_loose_object_property_names: false,
        },
    )?
    .ok_or_else(|| Error::msg("failed to deserialize empty .swcrc (json) file"))?;

    if let Ok(rc) = serde_json::from_value(v.clone()) {
        return Ok(rc);
    }

View on GitHub (pinned to 5176682b65)

Solutions

1. Fix the JSON at the reported line:column in .swcrc
2. Ensure the file matches the expected Rc config schema
3. Remove comments/trailing commas or use the JSONC-aware loading path

When it happens

Trigger: Thrown at crates/swc/src/lib.rs:1429 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of swc-project/swc@5176682b65 (2026-08-17). Data as JSON: /api/errors/320d0955834f1de6. Report an issue: GitHub.