astral-sh/uv · error · anyhow::Error

`{}` is not a valid Python download request; see `uv help py

Error message

`{}` is not a valid Python download request; see `uv help python` for supported formats and `uv python list --only-downloads` for available versions

What it means

Error "`{}` is not a valid Python download request; see `uv help python` for supported formats and `uv python list --only-downloads` for available versions" thrown in astral-sh/uv.

Source

Thrown at crates/uv/src/commands/python/install.rs:62

use crate::commands::{ExitStatus, conjunction, elapsed};
use crate::printer::Printer;

#[derive(Debug, Clone, PartialEq, Eq, Hash)]
struct InstallRequest<'a> {
    /// The original request from the user
    request: PythonRequest,
    /// A download request corresponding to the `request` with platform information filled
    download_request: PythonDownloadRequest,
    /// A download that satisfies the request
    download: &'a ManagedPythonDownload,
}

impl<'a> InstallRequest<'a> {
    fn new(request: PythonRequest, download_list: &'a ManagedPythonDownloadList) -> Result<Self> {
        // Make sure the request is a valid download request and fill platform information
        let download_request = PythonDownloadRequest::from_request(&request)
            .ok_or_else(|| {
                anyhow::anyhow!(
                    "`{}` is not a valid Python download request; see `uv help python` for supported formats and `uv python list --only-downloads` for available versions",
                    request.to_canonical_string()
                )
            })?
            .fill()?;

        // Find a matching download
        let download = match download_list.find(&download_request) {
            Ok(download) => download,
            Err(downloads::Error::NoDownloadFound(request))
                if request.libc().is_some_and(Libc::is_musl)
                    && request.arch().is_some_and(|arch| {
                        arch.inner() == Arch::from(&uv_platform_tags::Arch::Armv7L)
                    }) =>
            {
                return Err(anyhow::anyhow!(
                    "uv does not yet provide musl Python distributions on armv7."
                ));

View on GitHub (pinned to f1a42680ff)

When it happens

Trigger: Thrown at crates/uv/src/commands/python/install.rs:62 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/e0c4079d9d8981f5. Report an issue: GitHub.