Fix encoding error with location and refresh headers

packages/next/server/server-route-utils.ts

@@ -140,15 +140,25 @@ export const createRedirectRoute = ({
 // we need to re-encode them here but still allow passing through
 // values from rewrites/redirects
 export const stringifyQuery = (req: BaseNextRequest, query: ParsedUrlQuery) => {
-  const initialQueryValues = Object.values(
-    getRequestMeta(req, '__NEXT_INIT_QUERY') || {}
-  )
+  const initialQuery = getRequestMeta(req, '__NEXT_INIT_QUERY') || {}
+  const initialQueryValues: Array<string | string[]> =
+    Object.values(initialQuery)
 
   return stringifyQs(query, undefined, undefined, {
     encodeURIComponent(value) {
-      if (initialQueryValues.some((val) => val === value)) {
+      if (
+        value in initialQuery ||
+        initialQueryValues.some((initialQueryVal: string | string[]) => {
+          // `value` always refers to a query value, even if it's nested in an array
+          return Array.isArray(initialQueryVal)
+            ? initialQueryVal.includes(value)
+            : initialQueryVal === value
+        })
+      ) {
+        // Encode keys and values from initial query
         return encodeURIComponent(value)
       }
+
       return value
     },
   })

test/integration/custom-routes/test/index.test.js

@@ -690,6 +690,26 @@ const runTests = (isDev = false) => {
     expect(res.headers.get('refresh')).toBe(`0;url=/`)
   })
 
+  it('should have correctly encoded query in location and refresh headers', async () => {
+    const res = await fetchViaHTTP(
+      appPort,
+      // Query unencoded is ?テスト=あ
+      '/redirect4?%E3%83%86%E3%82%B9%E3%83%88=%E3%81%82',
+      undefined,
+      {
+        redirect: 'manual',
+      }
+    )
+    expect(res.status).toBe(308)
+
+    expect(res.headers.get('location').split('?')[1]).toBe(
+      '%E3%83%86%E3%82%B9%E3%83%88=%E3%81%82'
+    )
+    expect(res.headers.get('refresh')).toBe(
+      '0;url=/?%E3%83%86%E3%82%B9%E3%83%88=%E3%81%82'
+    )
+  })
+
   it('should handle basic api rewrite successfully', async () => {
     const data = await renderViaHTTP(appPort, '/api-hello')
     expect(JSON.parse(data)).toEqual({ query: {} })