feat: allow errors to be rendered by the route module

packages/next/src/server/base-server.ts

@@ -65,7 +65,11 @@ import * as Log from '../build/output/log'
 import escapePathDelimiters from '../shared/lib/router/utils/escape-path-delimiters'
 import { getUtils } from './server-utils'
 import isError, { getProperError } from '../lib/is-error'
-import { addRequestMeta, getRequestMeta } from './request-meta'
+import {
+  addRequestMeta,
+  getRequestMeta,
+  removeRequestMeta,
+} from './request-meta'
 
 import { ImageConfigComplete } from '../shared/lib/image-config'
 import { removePathPrefix } from '../shared/lib/router/utils/remove-path-prefix'
@@ -2529,6 +2533,17 @@ export default abstract class Server<ServerOptions extends Options = Options> {
         )
       }
 
+      // If the page has a route module, use it for the new match. If it doesn't
+      // have a route module, remove the match.
+      if (result.components.ComponentMod.routeModule) {
+        addRequestMeta(ctx.req, '_nextMatch', {
+          definition: result.components.ComponentMod.routeModule.definition,
+          params: undefined,
+        })
+      } else {
+        removeRequestMeta(ctx.req, '_nextMatch')
+      }
+
       try {
         return await this.renderToResponseWithComponents(
           {

packages/next/src/server/request-meta.ts

@@ -42,6 +42,14 @@ export interface RequestMeta {
   _nextMinimalMode?: boolean
 }
 
+/**
+ * Gets the request metadata. If no key is provided, the entire metadata object
+ * is returned.
+ *
+ * @param req the request to get the metadata from
+ * @param key the key to get from the metadata (optional)
+ * @returns the value for the key or the entire metadata object
+ */
 export function getRequestMeta(
   req: NextIncomingMessage,
   key?: undefined
@@ -58,11 +66,26 @@ export function getRequestMeta<K extends keyof RequestMeta>(
   return typeof key === 'string' ? meta[key] : meta
 }
 
+/**
+ * Sets the request metadata.
+ *
+ * @param req the request to set the metadata on
+ * @param meta the metadata to set
+ * @returns the mutated request metadata
+ */
 export function setRequestMeta(req: NextIncomingMessage, meta: RequestMeta) {
   req[NEXT_REQUEST_META] = meta
-  return getRequestMeta(req)
+  return meta
 }
 
+/**
+ * Adds a value to the request metadata.
+ *
+ * @param request the request to mutate
+ * @param key the key to set
+ * @param value the value to set
+ * @returns the mutated request metadata
+ */
 export function addRequestMeta<K extends keyof RequestMeta>(
   request: NextIncomingMessage,
   key: K,
@@ -73,6 +96,22 @@ export function addRequestMeta<K extends keyof RequestMeta>(
   return setRequestMeta(request, meta)
 }
 
+/**
+ * Removes a key from the request metadata.
+ *
+ * @param request the request to mutate
+ * @param key the key to remove
+ * @returns the mutated request metadata
+ */
+export function removeRequestMeta<K extends keyof RequestMeta>(
+  request: NextIncomingMessage,
+  key: K
+) {
+  const meta = getRequestMeta(request)
+  delete meta[key]
+  return setRequestMeta(request, meta)
+}
+
 type NextQueryMetadata = {
   __nextNotFoundSrcPage?: string
   __nextDefaultLocale?: string