fix: remove peer cache (#2786)

In cases where the peer store has grown very large (e.g. when a
well connected node has been online for a long time), the peer store
can get so large that this cache causes abnormal memory use.

The cache was added without any profiling, remove the cache for now,
we can add it back if it actually solves a problem

packages/peer-store/package.json

@@ -61,7 +61,6 @@
   "dependencies": {
     "@libp2p/crypto": "^5.0.5",
     "@libp2p/interface": "^2.1.3",
-    "@libp2p/peer-collections": "^6.0.9",
     "@libp2p/peer-id": "^5.0.6",
     "@libp2p/peer-record": "^8.0.9",
     "@multiformats/multiaddr": "^12.2.3",

packages/peer-store/src/store.ts

@@ -1,5 +1,4 @@
 import { InvalidParametersError } from '@libp2p/interface'
-import { PeerMap } from '@libp2p/peer-collections'
 import { peerIdFromCID } from '@libp2p/peer-id'
 import mortice, { type Mortice } from 'mortice'
 import { base32 } from 'multiformats/bases/base32'
@@ -20,37 +19,27 @@ export interface PeerUpdate extends PeerUpdateExternal {
   updated: boolean
 }
 
-function decodePeer (key: Key, value: Uint8Array, cache: PeerMap<Peer>): Peer {
+function decodePeer (key: Key, value: Uint8Array): Peer {
   // /peers/${peer-id-as-libp2p-key-cid-string-in-base-32}
   const base32Str = key.toString().split('/')[2]
   const buf = CID.parse(base32Str, base32)
   const peerId = peerIdFromCID(buf)
 
-  const cached = cache.get(peerId)
-
-  if (cached != null) {
-    return cached
-  }
-
-  const peer = bytesToPeer(peerId, value)
-
-  cache.set(peerId, peer)
-
-  return peer
+  return bytesToPeer(peerId, value)
 }
 
-function mapQuery (query: PeerQuery, cache: PeerMap<Peer>): Query {
+function mapQuery (query: PeerQuery): Query {
   if (query == null) {
     return {}
   }
 
   return {
     prefix: NAMESPACE_COMMON,
     filters: (query.filters ?? []).map(fn => ({ key, value }) => {
-      return fn(decodePeer(key, value, cache))
+      return fn(decodePeer(key, value))
     }),
     orders: (query.orders ?? []).map(fn => (a, b) => {
-      return fn(decodePeer(a.key, a.value, cache), decodePeer(b.key, b.value, cache))
+      return fn(decodePeer(a.key, a.value), decodePeer(b.key, b.value))
     })
   }
 }
@@ -131,10 +120,8 @@ export class PersistentStore {
   }
 
   async * all (query?: PeerQuery): AsyncGenerator<Peer, void, unknown> {
-    const peerCache = new PeerMap<Peer>()
-
-    for await (const { key, value } of this.datastore.query(mapQuery(query ?? {}, peerCache))) {
-      const peer = decodePeer(key, value, peerCache)
+    for await (const { key, value } of this.datastore.query(mapQuery(query ?? {}))) {
+      const peer = decodePeer(key, value)
 
       if (peer.id.equals(this.peerId)) {
         // Skip self peer if present