Ensure middleware has single data fetch on query hydration with valid props

packages/next/shared/lib/router/router.ts

@@ -427,7 +427,7 @@ const backgroundCache: Record<string, Promise<any>> = {}
 
 interface FetchDataOutput {
   dataHref: string
-  json: Record<string, any>
+  json: Record<string, any> | null
   response: Response
   text: string
 }
@@ -508,7 +508,7 @@ function fetchNextData({
 
           return {
             dataHref,
-            json: parseJSON ? tryToParseAsJSON(text) : {},
+            json: parseJSON ? tryToParseAsJSON(text) : null,
             response,
             text,
           }
@@ -552,7 +552,7 @@ function tryToParseAsJSON(text: string) {
   try {
     return JSON.parse(text)
   } catch (error) {
-    return {}
+    return null
   }
 }
 
@@ -1807,28 +1807,24 @@ export default class Router implements BaseRouter {
 
       const { props } = await this._getData(async () => {
         if (shouldFetchData && !useStreamedFlightData) {
-          const { json } =
-            data?.json &&
-            data?.response.headers
-              .get('content-type')
-              ?.includes('application/json')
-              ? data
-              : await fetchNextData({
-                  dataHref: this.pageLoader.getDataHref({
-                    href: formatWithValidation({ pathname, query }),
-                    asPath: resolvedAs,
-                    locale,
-                  }),
-                  isServerRender: this.isSsr,
-                  parseJSON: true,
-                  inflightCache: this.sdc,
-                  persistCache: !isPreview,
-                  isPrefetch: false,
-                  unstable_skipClientCache,
-                })
+          const { json } = data?.json
+            ? data
+            : await fetchNextData({
+                dataHref: this.pageLoader.getDataHref({
+                  href: formatWithValidation({ pathname, query }),
+                  asPath: resolvedAs,
+                  locale,
+                }),
+                isServerRender: this.isSsr,
+                parseJSON: true,
+                inflightCache: this.sdc,
+                persistCache: !isPreview,
+                isPrefetch: false,
+                unstable_skipClientCache,
+              })
 
           return {
-            props: json,
+            props: json || {},
           }
         }
 

test/e2e/middleware-rewrites/test/index.test.ts

@@ -27,6 +27,27 @@ describe('Middleware Rewrite', () => {
   testsWithLocale('/fr')
 
   function tests() {
+    it('should not have un-necessary data request on rewrite', async () => {
+      const browser = await webdriver(next.url, '/to-blog/first', {
+        waitHydration: false,
+      })
+      let requests = []
+
+      browser.on('request', (req) => {
+        requests.push(new URL(req.url()).pathname)
+      })
+
+      await check(
+        () => browser.eval(`next.router.isReady ? "yup" : "nope"`),
+        'yup'
+      )
+
+      expect(
+        requests.filter((url) => url === '/fallback-true-blog/first.json')
+          .length
+      ).toBeLessThan(2)
+    })
+
     it('should not mix component cache when navigating between dynamic routes', async () => {
       const browser = await webdriver(next.url, '/param-1')