fix(db-*): ensure consistent sorting even when sorting on non-unique fields or no sort parameters at all (#12447)

The databases do not keep track of document order internally so when
sorting by non-unique fields such as shared `order` number values, the
returned order will be random and not consistent.

While this issue is far more noticeable on mongo it could also occur in
postgres on certain environments.

This combined with pagination can lead to the perception of duplicated
or inconsistent data.

This PR adds a second sort parameter to queries so that we always have a
fallback, `-createdAt` will be used by default or `id` if timestamps are
disabled.

test/sort/config.ts

@@ -2,12 +2,14 @@ import type { CollectionSlug, Payload } from 'payload'
 
 import { fileURLToPath } from 'node:url'
 import path from 'path'
+import { wait } from 'payload/shared'
 
 import { buildConfigWithDefaults } from '../buildConfigWithDefaults.js'
 import { devUser } from '../credentials.js'
 import { DefaultSortCollection } from './collections/DefaultSort/index.js'
 import { DraftsCollection } from './collections/Drafts/index.js'
 import { LocalizedCollection } from './collections/Localized/index.js'
+import { NonUniqueSortCollection, nonUniqueSortSlug } from './collections/NonUniqueSort/index.js'
 import { OrderableCollection } from './collections/Orderable/index.js'
 import { OrderableJoinCollection } from './collections/OrderableJoin/index.js'
 import { PostsCollection } from './collections/Posts/index.js'
@@ -19,6 +21,7 @@ export default buildConfigWithDefaults({
     PostsCollection,
     DraftsCollection,
     DefaultSortCollection,
+    NonUniqueSortCollection,
     LocalizedCollection,
     OrderableCollection,
     OrderableJoinCollection,
@@ -87,6 +90,28 @@ async function seedSortable(payload: Payload) {
 
   await payload.create({ collection: 'orderable-join', data: { title: 'Join B' } })
 
+  // Create 10 items to be sorted by non-unique field
+  for (const i of Array.from({ length: 10 }, (_, index) => index)) {
+    let order = 1
+
+    if (i > 3) {
+      order = 2
+    } else if (i > 6) {
+      order = 3
+    }
+
+    await payload.create({
+      collection: nonUniqueSortSlug,
+      data: {
+        title: `Post ${i}`,
+        order,
+      },
+    })
+
+    // Wait 2 seconds to guarantee that the createdAt date is different
+    // await wait(2000)
+  }
+
   return new Response(JSON.stringify({ success: true }), {
     headers: { 'Content-Type': 'application/json' },
     status: 200,