Disallow iSSG revalidation period of zero (#9280)

* Disallow iSSG revalidation period of zero

* Fix revalidation period in test

packages/next/next-server/server/render.tsx

@@ -427,9 +427,9 @@ export async function renderToHTML(
 
       if (invalidKeys.length) {
         throw new Error(
-          `Additional keys were returned from \`getStaticProps\`. Properties intended for your component must be nested under the \`props\` key, e.g.:\n\n\treturn { props: { title: 'My Title', content: '...' }\n\nKeys that need moved: ${invalidKeys.join(
-            ', '
-          )}.
+          `Additional keys were returned from \`getStaticProps\`. Properties intended for your component must be nested under the \`props\` key, e.g.:` +
+            `\n\n\treturn { props: { title: 'My Title', content: '...' }` +
+            `\n\nKeys that need moved: ${invalidKeys.join(', ')}.
         `
         )
       }
@@ -442,12 +442,13 @@ export async function renderToHTML(
             }', cannot be used.` +
               `\nTry changing the value to '${Math.ceil(
                 data.revalidate
-              )}' or using \`Math.round()\` if you're computing the value.`
+              )}' or using \`Math.ceil()\` if you're computing the value.`
           )
-        } else if (data.revalidate < 0) {
+        } else if (data.revalidate <= 0) {
           throw new Error(
-            `A page's revalidate option can not be less than zero. A revalidate option of zero means to revalidate _after_ every request.` +
-              `\nTo never revalidate, you can set revalidate to \`false\` (only ran once at build-time).`
+            `A page's revalidate option can not be less than or equal to zero. A revalidate option of zero means to revalidate after _every_ request, and implies stale data cannot be tolerated.` +
+              `\n\nTo never revalidate, you can set revalidate to \`false\` (only ran once at build-time).` +
+              `\nTo revalidate as soon as possible, you can set the value to \`1\`.`
           )
         } else if (data.revalidate > 31536000) {
           // if it's greater than a year for some reason error

test/integration/prerender/pages/another/index.js

@@ -7,7 +7,7 @@ export async function unstable_getStaticProps () {
       world: 'world',
       time: new Date().getTime()
     },
-    revalidate: 0
+    revalidate: 1
   }
 }
 

test/integration/prerender/test/index.test.js

@@ -83,7 +83,7 @@ const expectedManifestRoutes = () => ({
   },
   '/another': {
     dataRoute: `/_next/data/${buildId}/another.json`,
-    initialRevalidateSeconds: 0,
+    initialRevalidateSeconds: 1,
     srcRoute: null
   },
   '/blog': {