fix: ensure data routes aren't added for app routes

Author: wyattjoh

packages/next/src/build/index.ts

@@ -2860,15 +2860,19 @@ export default async function build(
 
             if (!hasDynamicData && isDynamicRoute(originalAppPath)) {
               const normalizedRoute = normalizePagePath(page)
-              const dataRoute = path.posix.join(
-                `${normalizedRoute}${RSC_SUFFIX}`
-              )
 
-              let prefetchDataRoute: string | null | undefined
+              let dataRoute: string | null = null
+              if (!isRouteHandler) {
+                dataRoute = path.posix.join(`${normalizedRoute}${RSC_SUFFIX}`)
+              }
 
+              let prefetchDataRoute: string | null | undefined
+              if (isRouteHandler) {
+                prefetchDataRoute = null
+              }
               // We write the `.prefetch.rsc` when the app has PPR enabled, so
               // always add the prefetch data route to the manifest.
-              if (isAppPPREnabled) {
+              else if (isAppPPREnabled) {
                 prefetchDataRoute = path.posix.join(
                   `${normalizedRoute}${RSC_PREFETCH_SUFFIX}`
                 )
@@ -2896,7 +2900,7 @@ export default async function build(
                 fallback: appDynamicParamPaths.has(originalAppPath)
                   ? null
                   : false,
-                dataRouteRegex: isRouteHandler
+                dataRouteRegex: !dataRoute
                   ? null
                   : normalizeRouteRegex(
                       getNamedRouteRegex(
@@ -2905,18 +2909,17 @@ export default async function build(
                       ).re.source.replace(/\(\?:\\\/\)\?\$$/, '\\.rsc$')
                     ),
                 prefetchDataRoute,
-                prefetchDataRouteRegex:
-                  isRouteHandler || !prefetchDataRoute
-                    ? undefined
-                    : normalizeRouteRegex(
-                        getNamedRouteRegex(
-                          prefetchDataRoute.replace(/\.prefetch\.rsc$/, ''),
-                          false
-                        ).re.source.replace(
-                          /\(\?:\\\/\)\?\$$/,
-                          '\\.prefetch\\.rsc$'
-                        )
-                      ),
+                prefetchDataRouteRegex: !prefetchDataRoute
+                  ? undefined
+                  : normalizeRouteRegex(
+                      getNamedRouteRegex(
+                        prefetchDataRoute.replace(/\.prefetch\.rsc$/, ''),
+                        false
+                      ).re.source.replace(
+                        /\(\?:\\\/\)\?\$$/,
+                        '\\.prefetch\\.rsc$'
+                      )
+                    ),
               }
             }
           }