fix: correctly cache when using next export

src/helpers/cache.ts

@@ -1,20 +1,41 @@
-import { join } from 'path'
+import { existsSync } from 'fs'
+import { join, resolve } from 'path'
 
-export const restoreCache = async ({ cache, publish }) => {
-  const cacheDir = join(publish, 'cache')
+import { shouldSkip } from './utils'
+
+const findDistDir = (publish) => {
+  // In normal operation, the dist dir is the same as the publish dir
+  if (!shouldSkip()) {
+    return publish
+  }
+  // In this situation, the user has disabled the plugin, which means that they might be using next export,
+  // so we'll look in a few places to find the site root. This allows us to find the .next directory.
+  for (const root of [resolve(publish, '..'), resolve(publish, '..', '..')]) {
+    if (existsSync(join(root, 'next.config.js'))) {
+      return join(root, '.next')
+    }
+  }
+  return null
+}
 
-  if (await cache.restore(cacheDir)) {
+export const restoreCache = async ({ cache, publish }) => {
+  const distDir = findDistDir(publish)
+  if (!distDir) {
+    return
+  }
+  if (await cache.restore(join(distDir, 'cache'))) {
     console.log('Next.js cache restored.')
   } else {
     console.log('No Next.js cache to restore.')
   }
 }
 
 export const saveCache = async ({ cache, publish }) => {
-  const cacheDir = join(publish, 'cache')
-
-  const buildManifest = join(publish, 'build-manifest.json')
-  if (await cache.save(cacheDir, { digests: [buildManifest] })) {
+  const distDir = findDistDir(publish)
+  if (!distDir) {
+    return
+  }
+  if (await cache.save(join(distDir, 'cache'))) {
     console.log('Next.js cache saved.')
   } else {
     console.log('No Next.js cache to save.')

test/index.js

@@ -438,9 +438,7 @@ describe('onPostBuild', () => {
       utils: { ...utils, cache: { save }, functions: { list: jest.fn().mockResolvedValue([]) } },
     })
 
-    expect(save).toHaveBeenCalledWith(path.resolve('.next/cache'), {
-      digests: [path.resolve('.next/build-manifest.json')],
-    })
+    expect(save).toHaveBeenCalledWith(path.resolve('.next/cache'))
   })
 
   test('warns if old functions exist', async () => {