feat(kad): enable putting Record without publisher

protocols/kad/CHANGELOG.md

@@ -1,3 +1,6 @@
+  Add new `new_anonymous` function to enable putting Records without a publisher.
+  See [PR 6176](https://github.com/libp2p/rust-libp2p/pull/6176)
+
 ## 0.49.0
 
 - Remove no longer constructed GetRecordError::QuorumFailed.

protocols/kad/src/behaviour.rs

@@ -870,7 +870,10 @@ where
         mut record: Record,
         quorum: Quorum,
     ) -> Result<QueryId, store::Error> {
-        record.publisher = Some(*self.kbuckets.local_key().preimage());
+        record
+            .publisher
+            .and(Some(*self.kbuckets.local_key().preimage()));
+
         self.store.put(record.clone())?;
         record.expires = record
             .expires

protocols/kad/src/behaviour/test.rs

@@ -557,7 +557,7 @@ fn get_record_not_found() {
     }))
 }
 
-/// A node joining a fully connected network via three (ALPHA_VALUE) bootnodes
+/// A node joining a fully connected network via three (`ALPHA_VALUE`) bootnodes
 /// should be able to put a record to the X closest nodes of the network where X
 /// is equal to the configured replication factor.
 #[test]
@@ -609,6 +609,8 @@ fn put_record() {
         #[allow(clippy::mutable_key_type)] // False positive, we never modify `Bytes`.
         let records = records
             .into_iter()
+            // Exclude records without a publisher.
+            .filter(|r| r.publisher.is_some())
             .take(num_total)
             .map(|mut r| {
                 // We don't want records to expire prematurely, as they would

protocols/kad/src/record.rs

@@ -94,6 +94,16 @@ impl Record {
     where
         K: Into<Key>,
     {
+        Record {
+            key: key.into(),
+            value,
+            publisher: Some(PeerId::random()),
+            expires: None,
+        }
+    }
+
+    /// Creates a new record for insertion into the DHT.
+    pub fn new_anonymous(key: impl Into<Key>, value: Vec<u8>) -> Self {
         Record {
             key: key.into(),
             value,