astral-sh/uv · error

Cannot run a Python module from stdin

Error message

Cannot run a Python module from stdin

What it means

Error "Cannot run a Python module from stdin" thrown in astral-sh/uv.

Source

Thrown at crates/uv/src/commands/project/run.rs:1521

    /// Determine the [`ParsedRunCommand`] for a given set of arguments.
    pub(crate) fn from_args(
        command: &ExternalCommand,
        module: bool,
        script: bool,
        gui_script: bool,
    ) -> anyhow::Result<Self> {
        let (target, args) = command.split();
        let Some(target) = target else {
            return Ok(Self::Ready(RunCommand::Empty));
        };

        if target.eq_ignore_ascii_case("-") {
            let mut buf = Vec::with_capacity(1024);
            std::io::stdin().read_to_end(&mut buf)?;

            return if module {
                Err(anyhow!("Cannot run a Python module from stdin"))
            } else if gui_script {
                Ok(Self::Ready(RunCommand::PythonGuiStdin(buf, args.to_vec())))
            } else {
                Ok(Self::Ready(RunCommand::PythonStdin(buf, args.to_vec())))
            };
        }

        let target_path = PathBuf::from(target);

        // Determine whether the user provided a remote script.
        if target_path.starts_with("http://") || target_path.starts_with("https://") {
            // Only continue if we are absolutely certain no local file exists.
            //
            // We don't do this check on Windows since the file path would
            // be invalid anyway, and thus couldn't refer to a local file.
            if !cfg!(unix) || matches!(target_path.try_exists(), Ok(false)) {
                let url = DisplaySafeUrl::parse(&target.to_string_lossy())?;
                return Ok(Self::PendingRemote(PendingRemoteRunCommand {

View on GitHub (pinned to f1a42680ff)

When it happens

Trigger: Thrown at crates/uv/src/commands/project/run.rs:1521 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of astral-sh/uv@f1a42680ff (2026-08-16). Data as JSON: /api/errors/e608aa7458c4fb94. Report an issue: GitHub.