From 9d2cd9a89526992636b5365b4a0ac4396d43e457 Mon Sep 17 00:00:00 2001
From: Codex <codex@localhost>
Date: Fri, 30 Oct 2026 12:03:17 +0800
Subject: [PATCH] Preserve concurrent article mappings during static sync

---
 .../Commands/SyncLocalIllustrations.php       |  3 ++-
 app/Services/LocalIllustrations.php           | 23 +++++++++++++++++--
 tests/Feature/LocalIllustrationsTest.php      | 14 +++++++++++
 3 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/app/Console/Commands/SyncLocalIllustrations.php b/app/Console/Commands/SyncLocalIllustrations.php
index 96acb5e4..01c15931 100644
--- a/app/Console/Commands/SyncLocalIllustrations.php
+++ b/app/Console/Commands/SyncLocalIllustrations.php
@@ -20,6 +20,7 @@ public function handle(LocalIllustrations $local): int
             return self::FAILURE;
         }
         try {
+            $baseline = $local->selectionBaseline();
             $snapshots = [];
             $expected = [];
             foreach (config('illustrations.categories') as $category => $pool) {
@@ -33,7 +34,7 @@ public function handle(LocalIllustrations $local): int
                 $snapshots[$pool] = $snapshot;
                 $expected[$pool] = $keys;
             }
-            $result = $local->synchronize($snapshots);
+            $result = $local->synchronize($snapshots, $baseline);
             foreach ($expected as $pool => $keys) {
                 foreach ($keys as $key) {
                     if (! $local->thumbnail($pool, $key)) $result['pending'][$pool.':'.$key] ??= 'local_copy_unavailable';
diff --git a/app/Services/LocalIllustrations.php b/app/Services/LocalIllustrations.php
index 91af9652..22bcee6e 100644
--- a/app/Services/LocalIllustrations.php
+++ b/app/Services/LocalIllustrations.php
@@ -128,9 +128,16 @@ public function storeSelection(string $pool, string $slug, array $image): string
     }
 
     /** One atomic manifest switch after all downloadable files pass verification. */
-    public function synchronize(array $snapshots): array
+    public function selectionBaseline(): array
     {
-        return $this->locked(function () use ($snapshots) {
+        $this->manifest = null;
+        return $this->read()['selections'];
+    }
+
+    public function synchronize(array $snapshots, ?array $baseline = null): array
+    {
+        $baseline ??= $this->selectionBaseline();
+        return $this->locked(function () use ($snapshots, $baseline) {
             $state = $this->read();
             $pending = [];
             foreach ($snapshots as $pool => $snapshot) {
@@ -155,6 +162,18 @@ public function synchronize(array $snapshots): array
                         $pending[$pool.':'.$slug] = $reason;
                     }
                 }
+                // Receivers may publish new mappings while the remote snapshot is in flight.
+                // Never replace a local change made after this sync's baseline was captured.
+                $current = $state['selections'][$pool] ?? [];
+                $before = $baseline[$pool] ?? [];
+                foreach (array_unique(array_merge(array_keys($before), array_keys($current))) as $slug) {
+                    $exists = array_key_exists($slug, $current);
+                    if ($exists !== array_key_exists($slug, $before) || ($current[$slug] ?? null) !== ($before[$slug] ?? null)) {
+                        if ($exists) $selections[$slug] = $current[$slug];
+                        else unset($selections[$slug]);
+                        unset($pending[$pool.':'.$slug]);
+                    }
+                }
                 $state['selections'][$pool] = $selections;
             }
             $this->save($state);
diff --git a/tests/Feature/LocalIllustrationsTest.php b/tests/Feature/LocalIllustrationsTest.php
index fef8d132..48aa5d8a 100644
--- a/tests/Feature/LocalIllustrationsTest.php
+++ b/tests/Feature/LocalIllustrationsTest.php
@@ -125,4 +125,18 @@ public function test_missing_manifest_never_fetches_resource_or_returns_remote_f
         $this->assertSame('/tutorial.png', IllustrationPool::thumbnail(['iCategoryId' => 3, 'sSlug' => 'guide'], '/tutorial.png'));
         Http::assertNothingSent();
     }
+
+    public function test_sync_does_not_overwrite_concurrent_article_assignments(): void
+    {
+        $this->fakeImages();$local = app(LocalIllustrations::class);$old = $this->image();
+        $local->storeSelection('freenode', 'fn1', $old);
+        $baseline = $local->selectionBaseline();
+        $new = $this->image('33333333-3333-4333-8333-333333333333');
+        $local->storeSelection('freenode', 'fn1', $new);
+        $local->storeSelection('freenode', 'fn2', $new);
+        $local->synchronize(['freenode' => ['items' => [$old], 'selections' => ['fn1' => $old], 'unavailable' => []]], $baseline);
+        $state = json_decode(file_get_contents($this->dir.'/private/manifest.json'), true);
+        $this->assertSame($new['asset_id'], $state['selections']['freenode']['fn1']);
+        $this->assertSame($new['asset_id'], $state['selections']['freenode']['fn2']);
+    }
 }