[Take 2] Throw error if children entry can't be found, even if early access (github#35523)

Author: sarahs

lib/create-tree.js

@@ -30,14 +30,19 @@ export default async function createTree(originalPath, rootPath, previousTree) {
     try {
       mtime = await getMtime(filepath)
     } catch (error) {
-      if (error.code === 'ENOENT' && filepath.split(path.sep).includes('early-access')) {
-        // Do not throw an error if Early Access is not available.
-        console.warn(
-          `${filepath} could not be turned into a Page, but is ignored because it's early-access`
-        )
+      if (error.code !== 'ENOENT') {
+        throw error
+      }
+      // Throw an error if we can't find a content file associated with the children: entry.
+      // But don't throw an error if the user is running the site locally and hasn't cloned the Early Access repo.
+      if (originalPath === path.join('content', 'early-access')) {
         return
       }
-      throw error
+      throw new Error(
+        `Cannot find a content file at ${originalPath}. Fix the children frontmatter entry "/${path.basename(
+          originalPath
+        )}" in ${path.dirname(originalPath)}/index.md.\n`
+      )
     }
   }
 
@@ -114,9 +119,6 @@ export default async function createTree(originalPath, rootPath, previousTree) {
             // (early exit instead of returning a tree). So let's
             // mutate the `page.children` so we can benefit from the
             // ability to reload the site tree on consective requests.
-            if (child !== 'early-access') {
-              console.warn(`Remove '${child}' from ${item.page.children}`)
-            }
             item.page.children = item.page.children.filter((c) => c !== child)
           }
           return subTree

server.js

@@ -1,3 +1,7 @@
 import { main } from './start-server.js'
 
-main()
+try {
+  await main()
+} catch (error) {
+  console.error(error)
+}