astral-sh/ruff · error · Error

Cannot update non-system files (vendored files are read-only

Error message

Cannot update non-system files (vendored files are read-only)

What it means

A wasm-bindgen Error from ty's updateFile binding: the file handle's path is not a system path (for example a vendored path). Vendored and other non-system files are read-only in the wasm playground, so their contents cannot be updated.

Source

Thrown at crates/ty_wasm/src/lib.rs:217

            .write_file_all(&path, contents)
            .map_err(into_error)?;

        self.db.apply_changes(&[ChangeEvent::Opened(path.clone())]);

        let file = system_path_to_file(&self.db, &path).expect("File to exist");

        self.db.project().open_file(&mut self.db, file);

        Ok(FileHandle {
            path: path.into(),
            file,
        })
    }

    #[wasm_bindgen(js_name = "updateFile")]
    pub fn update_file(&mut self, file_id: &FileHandle, contents: &str) -> Result<(), Error> {
        let system_path = file_id.path.as_system_path().ok_or_else(|| {
            Error::new("Cannot update non-system files (vendored files are read-only)")
        })?;

        if !self.system.fs.exists(system_path) {
            return Err(Error::new("File does not exist"));
        }

        self.system
            .fs
            .write_file(system_path, contents)
            .map_err(into_error)?;

        self.db.apply_changes(&[
            ChangeEvent::Changed {
                path: system_path.to_path_buf(),
                kind: ChangedKind::FileContent,
            },
            ChangeEvent::Changed {
                path: system_path.to_path_buf(),

View on GitHub (pinned to 26f38c119c)

Solutions

1. Only call updateFile on files created via the system API
2. Re-create the file as a system file instead of updating a vendored one

When it happens

Trigger: Thrown at crates/ty_wasm/src/lib.rs:217 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of astral-sh/ruff@26f38c119c (2026-09-05). Data as JSON: /api/errors/8e183d01b412d1d5. Report an issue: GitHub.