From 95aed2b220010670031799ca7fbe593424ab6f1f Mon Sep 17 00:00:00 2001
From: Etan Kissling <etan@status.im>
Date: Thu, 28 Mar 2024 01:38:49 +0100
Subject: [PATCH] filter out `nil` values when iterating peers

Iterating peers should only yield peers present in registry, otherwise
`nil` pointers are returned and depending on comparison function it will
break, see #6149.
---
 beacon_chain/networking/peer_pool.nim | 34 +++++++++++++--------------
 1 file changed, 17 insertions(+), 17 deletions(-)

diff --git a/beacon_chain/networking/peer_pool.nim b/beacon_chain/networking/peer_pool.nim
index cc21f05e1..379165d43 100644
--- a/beacon_chain/networking/peer_pool.nim
+++ b/beacon_chain/networking/peer_pool.nim
@@ -652,12 +652,12 @@ iterator peers*[A, B](pool: PeerPool[A, B],
   ## All peers will be sorted by equation `>`(Peer1, Peer2), so biggest values
   ## will be first.
   var sorted = initHeapQueue[PeerIndex]()
-  for i in 0 ..< len(pool.storage):
-    if pool.storage[i].peerType in filter:
-      sorted.push(PeerIndex(data: i, cmp: pool.cmp))
+  for peerIdx in pool.registry.values():
+    if pool.storage[peerIdx.data].peerType in filter:
+      sorted.push(peerIdx)
   while len(sorted) > 0:
-    let pindex = sorted.pop().data
-    yield pool.storage[pindex].data
+    let peerIdx = sorted.pop()
+    yield pool.storage[peerIdx.data].data
 
 iterator availablePeers*[A, B](pool: PeerPool[A, B],
                                filter = {PeerType.Incoming,
@@ -667,13 +667,13 @@ iterator availablePeers*[A, B](pool: PeerPool[A, B],
   ## All peers will be sorted by equation `>`(Peer1, Peer2), so biggest values
   ## will be first.
   var sorted = initHeapQueue[PeerIndex]()
-  for i in 0 ..< len(pool.storage):
-    if (PeerFlags.Acquired notin pool.storage[i].flags) and
-       (pool.storage[i].peerType in filter):
-      sorted.push(PeerIndex(data: i, cmp: pool.cmp))
+  for peerIdx in pool.registry.values():
+    if (PeerFlags.Acquired notin pool.storage[peerIdx.data].flags) and
+       (pool.storage[peerIdx.data].peerType in filter):
+      sorted.push(peerIdx)
   while len(sorted) > 0:
-    let pindex = sorted.pop().data
-    yield pool.storage[pindex].data
+    let peerIdx = sorted.pop()
+    yield pool.storage[peerIdx.data].data
 
 iterator acquiredPeers*[A, B](pool: PeerPool[A, B],
                               filter = {PeerType.Incoming,
@@ -683,13 +683,13 @@ iterator acquiredPeers*[A, B](pool: PeerPool[A, B],
   ## All peers will be sorted by equation `>`(Peer1, Peer2), so biggest values
   ## will be first.
   var sorted = initHeapQueue[PeerIndex]()
-  for i in 0 ..< len(pool.storage):
-    if (PeerFlags.Acquired in pool.storage[i].flags) and
-       (pool.storage[i].peerType in filter):
-      sorted.push(PeerIndex(data: i, cmp: pool.cmp))
+  for peerIdx in pool.registry.values():
+    if (PeerFlags.Acquired in pool.storage[peerIdx.data].flags) and
+       (pool.storage[peerIdx.data].peerType in filter):
+      sorted.push(peerIdx)
   while len(sorted) > 0:
-    let pindex = sorted.pop().data
-    yield pool.storage[pindex].data
+    let peerIdx = sorted.pop()
+    yield pool.storage[peerIdx.data].data
 
 proc `[]`*[A, B](pool: PeerPool[A, B], key: B): A {.inline, raises: [KeyError].} =
   ## Retrieve peer with key ``key`` from PeerPool ``pool``.