astral-sh/uv · error · anyhow::Error

`install_blocking` task panicked

Error message

`install_blocking` task panicked

What it means

Error "`install_blocking` task panicked" thrown in astral-sh/uv.

Source

Thrown at crates/uv-installer/src/installer.rs:129

        initialize_rayon_once();
        rayon::spawn(move || {
            let result = install(
                wheels,
                &layout,
                installer_name.as_deref(),
                link_mode,
                reporter.as_ref(),
                relocatable,
                installer_metadata,
                preview,
            );

            // This may fail if the main task was cancelled.
            let _ = tx.send(result);
        });

        rx.await
            .map_err(|_| anyhow::anyhow!("`install_blocking` task panicked"))
            .and_then(convert::identity)
    }

    /// Install a set of wheels into a Python virtual environment synchronously.
    #[instrument(skip_all, fields(num_wheels = %wheels.len()))]
    pub fn install_blocking(self, wheels: Vec<CachedDist>) -> Result<Vec<CachedDist>> {
        if self.cache.is_some_and(Cache::is_temporary) {
            if self.link_mode.is_symlink() {
                return Err(anyhow::anyhow!(
                    "Symlink-based installation is not supported with `--no-cache`. The created environment will be rendered unusable by the removal of the cache."
                ));
            }
        }

        install(
            wheels,
            &self.venv.interpreter().layout(),
            self.name.as_deref(),

View on GitHub (pinned to f1a42680ff)

When it happens

Trigger: Thrown at crates/uv-installer/src/installer.rs:129 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/3e5897ceff7a51e3. Report an issue: GitHub.