From 17742f9ed237fb91e0392809b01bedcd277d48bc Mon Sep 17 00:00:00 2001
From: Andre Staltz <andre@staltz.com>
Date: Wed, 17 Jan 2024 15:47:58 +0200
Subject: [PATCH] avoid infinite loop in Tangle.precedes()

---
 lib/msg-v4/tangle.js | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/lib/msg-v4/tangle.js b/lib/msg-v4/tangle.js
index 276a178..9e0c6fa 100644
--- a/lib/msg-v4/tangle.js
+++ b/lib/msg-v4/tangle.js
@@ -296,13 +296,19 @@ class Tangle {
     if (msgAID === msgBID) return false
     if (msgBID === this.#rootID) return false
     let toCheck = [msgBID]
+    const checked = new Set()
     while (toCheck.length > 0) {
       const checking = /** @type {string} */ (toCheck.shift())
+      checked.add(checking)
       const prev = this.#prev.get(checking)
       if (!prev) continue
-      if (prev.includes(msgAID)) return true
-      toCheck.push(...prev)
+      if (prev.includes(msgAID)) {
+        checked.clear()
+        return true
+      }
+      toCheck.push(...prev.filter((p) => !checked.has(p)))
     }
+    checked.clear()
     return false
   }