From 848cdf763e34034df3315544915f914e1daa282d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20Lohrer?= <info.empeiria@gmail.com>
Date: Tue, 28 Apr 2026 08:19:20 +0200
Subject: [PATCH] fix(snapshot): NIP-09-filter beachtet zeitliche reihenfolge

Per NIP-09 darf ein deletion nur events mit created_at <= deletion.created_at
loeschen. Vorher wurde ein re-publizierter post nach geloeschtem vorgaenger
stumm wegfiltern. Code-review-feedback aus etappe 2.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
---
 snapshot/src/core/nip09-filter.ts   | 11 ++++++++---
 snapshot/tests/nip09-filter.test.ts | 27 +++++++++++++++++++++++++++
 2 files changed, 35 insertions(+), 3 deletions(-)

diff --git a/snapshot/src/core/nip09-filter.ts b/snapshot/src/core/nip09-filter.ts
index cd2d602..0caaf7e 100644
--- a/snapshot/src/core/nip09-filter.ts
+++ b/snapshot/src/core/nip09-filter.ts
@@ -5,18 +5,23 @@ export function filterDeleted(
   deletions: SignedEvent[],
   authorPubkey: string,
 ): SignedEvent[] {
-  const deletedCoords = new Set<string>()
+  const deletedAtByCoord = new Map<string, number>()
   for (const del of deletions) {
     if (del.kind !== 5) continue
     if (del.pubkey !== authorPubkey) continue
     for (const tag of del.tags) {
-      if (tag[0] === 'a' && tag[1]) deletedCoords.add(tag[1])
+      if (tag[0] !== 'a' || !tag[1]) continue
+      const previous = deletedAtByCoord.get(tag[1])
+      if (previous === undefined || del.created_at > previous) {
+        deletedAtByCoord.set(tag[1], del.created_at)
+      }
     }
   }
   return events.filter((ev) => {
     const d = ev.tags.find((t) => t[0] === 'd')?.[1]
     if (!d) return true
     const coord = `${ev.kind}:${ev.pubkey}:${d}`
-    return !deletedCoords.has(coord)
+    const deletedAt = deletedAtByCoord.get(coord)
+    return deletedAt === undefined || ev.created_at > deletedAt
   })
 }
diff --git a/snapshot/tests/nip09-filter.test.ts b/snapshot/tests/nip09-filter.test.ts
index 0eabf6b..2112709 100644
--- a/snapshot/tests/nip09-filter.test.ts
+++ b/snapshot/tests/nip09-filter.test.ts
@@ -28,3 +28,30 @@ Deno.test('filterDeleted ignoriert kind:5 fremder pubkeys', () => {
   const out = filterDeleted([post('alive', 'a')], [fremde], 'P')
   assertEquals(out.length, 1)
 })
+
+Deno.test('filterDeleted: re-publizierter post (post.created_at > deletion.created_at) bleibt erhalten', () => {
+  const oldDelete: SignedEvent = {
+    id: 'del', pubkey: 'P', created_at: 100, kind: 5, sig: 's', content: '',
+    tags: [['a', '30023:P:resurrected']],
+  }
+  const newPost: SignedEvent = {
+    id: 'new', pubkey: 'P', created_at: 200, kind: 30023, sig: 's', content: '',
+    tags: [['d', 'resurrected']],
+  }
+  const out = filterDeleted([newPost], [oldDelete], 'P')
+  assertEquals(out.length, 1)
+  assertEquals(out[0].id, 'new')
+})
+
+Deno.test('filterDeleted: post mit created_at <= deletion.created_at wird entfernt', () => {
+  const newDelete: SignedEvent = {
+    id: 'del', pubkey: 'P', created_at: 200, kind: 5, sig: 's', content: '',
+    tags: [['a', '30023:P:dead']],
+  }
+  const oldPost: SignedEvent = {
+    id: 'old', pubkey: 'P', created_at: 100, kind: 30023, sig: 's', content: '',
+    tags: [['d', 'dead']],
+  }
+  const out = filterDeleted([oldPost], [newDelete], 'P')
+  assertEquals(out.length, 0)
+})