[next] Ensure $$ in ISR page is handled correctly (vercel#8359)

* Ensure $$ in ISR page is handled correctly

* update test

* Remove duplicate tests

* add comment

* tweak

Author: ijjk

packages/next/src/utils.ts

@@ -1832,7 +1832,10 @@ export const onPrerenderRoute =
     if (nonDynamicSsg || isFallback || isOmitted) {
       outputPathData = outputPathData.replace(
         new RegExp(`${escapeStringRegexp(origRouteFileNoExt)}.json$`),
-        `${routeFileNoExt}.json`
+        // ensure we escape "$" correctly while replacing as "$" is a special
+        // character, we need to do double escaping as first is for the initial
+        // replace on the routeFile and then the second on the outputPath
+        `${routeFileNoExt.replace(/\$/g, '$$$$')}.json`
       );
     }
 

packages/next/test/fixtures/00-i18n-support/pages/$$.js

@@ -0,0 +1,19 @@
+function Page({ date }) {
+  return (
+    <>
+      <h1>$$</h1>
+      <p>Date: {date}</p>
+    </>
+  );
+}
+
+export async function getStaticProps() {
+  return {
+    props: {
+      date: new Date().toISOString(),
+      page: '$$',
+    },
+  };
+}
+
+export default Page;

packages/next/test/fixtures/00-i18n-support/pages/$$b.js

@@ -0,0 +1,20 @@
+function Page({ date }) {
+  return (
+    <>
+      <h1>$$b</h1>
+      <p>Date: {date}</p>
+    </>
+  );
+}
+
+export async function getStaticProps() {
+  return {
+    props: {
+      date: new Date().toISOString(),
+      page: '$$b',
+    },
+    revalidate: 5,
+  };
+}
+
+export default Page;

packages/next/test/fixtures/00-i18n-support/pages/b$$.js

@@ -0,0 +1,20 @@
+function Page({ date }) {
+  return (
+    <>
+      <h1>b$$</h1>
+      <p>Date: {date}</p>
+    </>
+  );
+}
+
+export async function getStaticProps() {
+  return {
+    props: {
+      date: new Date().toISOString(),
+      page: 'b$$',
+    },
+    revalidate: 5,
+  };
+}
+
+export default Page;

packages/next/test/fixtures/00-i18n-support/vercel.json

@@ -7,6 +7,36 @@
     }
   ],
   "probes": [
+    {
+      "path": "/$$",
+      "status": 200,
+      "mustContain": ">$$<"
+    },
+    {
+      "path": "/_next/data/testing-build-id/en/$$.json",
+      "status": 200,
+      "mustContain": "\"$$\""
+    },
+    {
+      "path": "/$$b",
+      "status": 200,
+      "mustContain": ">$$b<"
+    },
+    {
+      "path": "/_next/data/testing-build-id/en/$$b.json",
+      "status": 200,
+      "mustContain": "\"$$b\""
+    },
+    {
+      "path": "/b$$",
+      "status": 200,
+      "mustContain": ">b$$<"
+    },
+    {
+      "path": "/_next/data/testing-build-id/en/b$$.json",
+      "status": 200,
+      "mustContain": "\"b$$\""
+    },
     {
       "path": "/",
       "headers": {

packages/next/test/fixtures/00-server-build/pages/$$.js

@@ -0,0 +1,20 @@
+function Page({ date }) {
+  return (
+    <>
+      <h1>$$</h1>
+      <p>Date: {date}</p>
+    </>
+  );
+}
+
+export async function getStaticProps() {
+  return {
+    props: {
+      date: new Date().toISOString(),
+      page: '$$',
+    },
+    revalidate: 5,
+  };
+}
+
+export default Page;

packages/next/test/fixtures/00-server-build/pages/$$b.js

@@ -0,0 +1,20 @@
+function Page({ date }) {
+  return (
+    <>
+      <h1>$$b</h1>
+      <p>Date: {date}</p>
+    </>
+  );
+}
+
+export async function getStaticProps() {
+  return {
+    props: {
+      date: new Date().toISOString(),
+      page: '$$b',
+    },
+    revalidate: 5,
+  };
+}
+
+export default Page;

packages/next/test/fixtures/00-server-build/pages/b$$.js

@@ -0,0 +1,20 @@
+function Page({ date }) {
+  return (
+    <>
+      <h1>b$$</h1>
+      <p>Date: {date}</p>
+    </>
+  );
+}
+
+export async function getStaticProps() {
+  return {
+    props: {
+      date: new Date().toISOString(),
+      page: 'b$$',
+    },
+    revalidate: 5,
+  };
+}
+
+export default Page;

packages/next/test/fixtures/00-server-build/vercel.json

@@ -26,6 +26,36 @@
     }
   ],
   "probes": [
+    {
+      "path": "/$$",
+      "status": 200,
+      "mustContain": ">$$<"
+    },
+    {
+      "path": "/_next/data/testing-build-id/$$.json",
+      "status": 200,
+      "mustContain": "\"$$\""
+    },
+    {
+      "path": "/$$b",
+      "status": 200,
+      "mustContain": ">$$b<"
+    },
+    {
+      "path": "/_next/data/testing-build-id/$$b.json",
+      "status": 200,
+      "mustContain": "\"$$b\""
+    },
+    {
+      "path": "/b$$",
+      "status": 200,
+      "mustContain": ">b$$<"
+    },
+    {
+      "path": "/_next/data/testing-build-id/b$$.json",
+      "status": 200,
+      "mustContain": "\"b$$\""
+    },
     {
       "path": "/",
       "status": 200,