test(release): [REL-04] checkpoint exact historical Pages recovery

scripts/pages/recovery.ts

@@ -0,0 +1,40 @@
+import assert from 'node:assert/strict'
+import { createHash } from 'node:crypto'
+import fs from 'node:fs'
+import { inside, inventory } from './artifact.ts'
+
+export interface GitFile { objectId: string, bytes: number }
+
+export function verifyRestoredTree(root: string, expected: Record<string, GitFile>) {
+  const files = inventory(root)
+  assert.deepEqual(Object.keys(files).sort(), Object.keys(expected).sort(), 'Restored site has missing or additional files')
+  for (const [relative, identity] of Object.entries(expected)) {
+    const bytes = fs.readFileSync(inside(root, relative))
+    assert.equal(bytes.length, identity.bytes, `Restored file size differs: ${relative}`)
+    const objectId = createHash('sha1').update(`blob ${bytes.length}\0`).update(bytes).digest('hex')
+    assert.equal(objectId, identity.objectId, `Restored Git blob differs: ${relative}`)
+  }
+  return files
+}
+
+export function replaceRehearsalSite(run: string, expected: Record<string, GitFile>) {
+  const root = fs.realpathSync(run)
+  const live = inside(root, 'site')
+  const prepared = inside(root, 'prepared')
+  const failed = inside(root, 'failed-site')
+  assert(!fs.existsSync(failed), 'Previous failed snapshot must not be overwritten')
+  for (const directory of [live, prepared]) {
+    assert.equal(fs.realpathSync(directory), directory, 'Rehearsal directories must not be links')
+    assert(fs.lstatSync(directory).isDirectory())
+  }
+  verifyRestoredTree(prepared, expected)
+  fs.renameSync(live, failed)
+  try {
+    fs.renameSync(prepared, live)
+  }
+  catch (error) {
+    fs.renameSync(failed, live)
+    throw error
+  }
+  return verifyRestoredTree(live, expected)
+}