From b0550d62ca6982005d878884cd2584c220b36929 Mon Sep 17 00:00:00 2001
From: Steven Vandevelde <steven@tokono.ma>
Date: Tue, 13 Oct 2026 21:52:46 +0200
Subject: [PATCH] chore: some loader improvements

---
 src/common/loader.js        | 41 ++++++++++++++++++++++++++++++++++++-
 src/l/index.js              |  9 +++++++-
 src/styles/loader-fonts.css |  8 ++++++++
 3 files changed, 56 insertions(+), 2 deletions(-)
 create mode 100644 src/styles/loader-fonts.css

diff --git a/src/common/loader.js b/src/common/loader.js
index daa4991f..bd027795 100644
--- a/src/common/loader.js
+++ b/src/common/loader.js
@@ -157,7 +157,18 @@ export function createLoader(config) {
     }).then(() => {
       if (loadable.id === loadedId) return;
       loadedId = loadable.id ?? null;
-      config.render(loadable);
+      // A throwing/rejecting `render` would otherwise escape as an unhandled
+      // rejection, leaving the spinner bouncing with no message.
+      return Promise.resolve()
+        .then(() => config.render(loadable))
+        .catch((err) => {
+          if (swControllerChanging) return;
+          renderError(
+            container,
+            `Failed to render ${config.label.toLowerCase()}`,
+            { context: err, throw: true },
+          );
+        });
     });
   });
 }
@@ -222,6 +233,11 @@ export async function ensureHTML(item) {
         blocks: tile.blocks,
       },
     });
+  } else if (item.uri?.endsWith(".tile") || item.resources) {
+    // A tile that resolved no root (missing `/` resource, CID, or block bytes)
+    // would otherwise fall through to loading the `.tile` binary as text and
+    // inject garbage.
+    throw new Error("Tile has no root resource");
   } else if (item.uri) {
     loaded = /** @type {T} */ ({ ...item, html: await loadURI(item.uri) });
   }
@@ -461,12 +477,35 @@ export function linkTileResources(container, resources, blocks) {
   }
 }
 
+/**
+ * Loads the site font styles when an error is first rendered. The loader page
+ * doesn't include them upfront, so the woff2 is only fetched when the error
+ * message actually renders with the family (@font-face fonts are downloaded
+ * lazily, on first use).
+ */
+function loadErrorStyles() {
+  // `styles/base.css` already registers the font faces.
+  if (
+    document.querySelector(
+      `link[href="styles/loader-fonts.css"], link[href="styles/base.css"]`,
+    )
+  ) {
+    return;
+  }
+
+  const link = document.createElement("link");
+  link.rel = "stylesheet";
+  link.href = "styles/loader-fonts.css";
+  document.head.append(link);
+}
+
 /**
  * @param {HTMLElement} container
  * @param {string} error
  * @param {{ context?: Error; throw?: boolean }} [options]
  */
 export function renderError(container, error, options) {
+  loadErrorStyles();
   document.querySelector("#diffuse-loader")?.classList.add("loaded");
   container.classList.add("has-loaded");
   container.innerHTML = `
diff --git a/src/l/index.js b/src/l/index.js
index b3ddf195..88f1b166 100644
--- a/src/l/index.js
+++ b/src/l/index.js
@@ -21,7 +21,14 @@ if (!window.isSecureContext) {
 }
 
 // Output element
-const output = await foundation.orchestrator.output();
+// Without the orchestrator there's nothing to load, so surface the failure
+// instead of leaving the spinner bouncing forever on an unhandled rejection.
+const output = await foundation.orchestrator.output().catch((err) => {
+  renderError(container, "Failed to initialize the output orchestrator", {
+    context: err,
+  });
+  throw err;
+});
 
 // Preludes
 const facets = await Output.data(output.facets);
diff --git a/src/styles/loader-fonts.css b/src/styles/loader-fonts.css
new file mode 100644
index 00000000..98dcf8b7
--- /dev/null
+++ b/src/styles/loader-fonts.css
@@ -0,0 +1,8 @@
+/*
+ * Fonts for pages that don't load `base.css` (e.g. the `/l/` loader), injected
+ * on demand when a loader error is rendered. Declared at this depth (not in
+ * `diffuse/`) because imports are inlined without rebasing URLs, so
+ * `font-faces.css`'s `../fonts/` only resolves from this directory.
+ */
+@import "./diffuse/font-faces.css" layer(diffuse.font-faces);
+@import "./diffuse/fonts.css" layer(diffuse.fonts);
-- 
2.51.2