Fix 'Failed to resolve import' crash during ssr (#1496)

* catch import errors in lazyRoute in dev

* provide placeholder component when error occurs

* fallback to empty route

* Create mighty-teachers-guess.md

---------

Co-authored-by: Ryan Carniato <[email protected]>

.changeset/mighty-teachers-guess.md

@@ -0,0 +1,5 @@
+---
+"@solidjs/start": patch
+---
+
+Fix 'Failed to resolve import' crash during ssr

packages/start/src/router/lazyRoute.ts

@@ -10,10 +10,15 @@ export default function lazyRoute<T>(component: any, clientManifest: any, server
     if (import.meta.env.DEV) {
       let manifest = import.meta.env.SSR ? serverManifest : clientManifest;
 
-      const mod = await manifest.inputs[component.src].import();
+      // import() throws if a module doesn't exist, which includes any
+      // modules loaded by the route itself, so it's important we catch here
+      const mod = await manifest.inputs[component.src].import().catch(() => null);
+      // fallback to an empty component as any errors will surface in the vite overlay
+      if(!mod) return { default: () => [] };
+
       if (!mod[exported]) console.error(`Module ${component.src} does not export ${exported}`);
-      const Component = mod[exported];
-      let assets = await clientManifest.inputs?.[component.src].assets();
+      const Component = mod[exported]
+      let assets = await clientManifest.inputs?.[component.src]?.assets();
       const styles = assets.filter((asset: Asset) => asset.tag === "style");
 
       if (typeof window !== "undefined" && import.meta.hot) {

packages/start/src/server/StartServer.tsx

@@ -36,7 +36,7 @@ export function StartServer(props: { document: Component<DocumentComponentProps>
   // @ts-ignore
   const nonce = context.nonce;
 
-  let assets: Asset[];
+  let assets: Asset[]  = [];
   Promise.resolve().then(async () => {
     let assetPromises: Promise<Asset[]>[] = [];
     // @ts-ignore