emilk/egui · error

failed to spawn thread

Error message

failed to spawn thread

What it means

Error "failed to spawn thread" thrown in emilk/egui.

Source

Thrown at crates/egui_extras/src/loaders/image_loader.rs:132

                                true
                            } else {
                                log::trace!("ImageLoader - canceled loading {uri:?}\nNote: This can happen if `forget_image` is called while the image is still loading.");
                                false
                            }
                        };
                        // We may not lock Context while the cache lock is held, since this can
                        // deadlock.
                        // Example deadlock scenario:
                        // - loader thread: lock cache
                        // - main thread: lock ctx (e.g. in `Context::has_pending_images`)
                        // - loader thread: try to lock ctx (in `request_repaint`)
                        // - main thread: try to lock cache (from `Self::has_pending`)
                        if repaint {
                            ctx.request_repaint();
                        }
                    }
                })
                .expect("failed to spawn thread");

            Ok(ImagePoll::Pending { size: None })
        }

        #[cfg(target_arch = "wasm32")]
        fn load_image(
            _ctx: &egui::Context,
            uri: &str,
            cache: &Arc<Mutex<HashMap<String, Entry>>>,
            bytes: &Bytes,
        ) -> ImageLoadResult {
            let mut cache_lock = cache.lock();
            log::trace!("started loading {uri:?}");
            let result = crate::image::load_image_bytes(bytes)
                .map(Arc::new)
                .map_err(|err| err.to_string());
            log::trace!("finished loading {uri:?}");
            cache_lock.insert(uri.into(), core::task::Poll::Ready(result.clone()));

View on GitHub (pinned to d802a982ce)

When it happens

Trigger: Thrown at crates/egui_extras/src/loaders/image_loader.rs:132 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of emilk/egui@d802a982ce (2026-08-16). Data as JSON: /api/errors/74f1abdc3b9a60db. Report an issue: GitHub.