From 284913e5f224a52306345ddd0d6f2bd2eba1743d Mon Sep 17 00:00:00 2001
From: Niklas Adolfsson <niklasadolfsson1@gmail.com>
Date: Mon, 11 Mar 2024 23:26:49 +0100
Subject: [PATCH] address grumbles

---
 .../backend/unstable/follow_stream_unpin.rs   | 21 ++++++++++++-------
 .../src/full_client/client/unstable_rpcs.rs   | 20 +++++++-----------
 2 files changed, 21 insertions(+), 20 deletions(-)

diff --git a/subxt/src/backend/unstable/follow_stream_unpin.rs b/subxt/src/backend/unstable/follow_stream_unpin.rs
index d4164a9d903..6a01f35e9ba 100644
--- a/subxt/src/backend/unstable/follow_stream_unpin.rs
+++ b/subxt/src/backend/unstable/follow_stream_unpin.rs
@@ -115,15 +115,20 @@ impl<Hash: BlockHash> Stream for FollowStreamUnpin<Hash> {
                 }
                 FollowStreamMsg::Event(FollowEvent::Initialized(details)) => {
                     // The first finalized block gets the starting block_num.
-                    let rel_block_num = this.rel_block_num;
-                    // Pin this block, but note that it can be unpinned any time since it won't show up again (except
-                    // as a parent block, which we are ignoring at the moment).
+                    let mut rel_block_num = this.rel_block_num;
 
-                    let finalized_block_hashes = details
-                        .finalized_block_hashes
-                        .iter()
-                        .map(|h| this.pin_unpinnable_block_at(rel_block_num, *h))
-                        .collect();
+                    let mut finalized_block_hashes =
+                        Vec::with_capacity(details.finalized_block_hashes.len());
+
+                    for finalized_block in &details.finalized_block_hashes {
+                        // Pin this block, but note that it can be unpinned any time since it won't show up again (except
+                        // as a parent block, which we are ignoring at the moment).
+                        let block_ref =
+                            this.pin_unpinnable_block_at(rel_block_num, *finalized_block);
+
+                        finalized_block_hashes.push(block_ref);
+                        rel_block_num += 1;
+                    }
 
                     FollowStreamMsg::Event(FollowEvent::Initialized(Initialized {
                         finalized_block_hashes,
diff --git a/testing/integration-tests/src/full_client/client/unstable_rpcs.rs b/testing/integration-tests/src/full_client/client/unstable_rpcs.rs
index d32a5d9deac..3752b397479 100644
--- a/testing/integration-tests/src/full_client/client/unstable_rpcs.rs
+++ b/testing/integration-tests/src/full_client/client/unstable_rpcs.rs
@@ -97,12 +97,11 @@ async fn chainhead_unstable_header() {
 
     let mut blocks = rpc.chainhead_unstable_follow(false).await.unwrap();
     let event = blocks.next().await.unwrap().unwrap();
-    let hashes = match event {
-        FollowEvent::Initialized(init) => init.finalized_block_hashes,
+    let hash = match event {
+        FollowEvent::Initialized(init) => init.finalized_block_hashes.last().unwrap().clone(),
         _ => panic!("Unexpected event"),
     };
     let sub_id = blocks.subscription_id().unwrap();
-    let hash = hashes[0];
 
     let new_header = legacy_rpc
         .chain_get_header(Some(hash))
@@ -126,12 +125,11 @@ async fn chainhead_unstable_storage() {
 
     let mut blocks = rpc.chainhead_unstable_follow(false).await.unwrap();
     let event = blocks.next().await.unwrap().unwrap();
-    let hashes = match event {
-        FollowEvent::Initialized(init) => init.finalized_block_hashes,
+    let hash = match event {
+        FollowEvent::Initialized(init) => init.finalized_block_hashes.last().unwrap().clone(),
         _ => panic!("Unexpected event"),
     };
     let sub_id = blocks.subscription_id().unwrap();
-    let hash = hashes[0];
 
     let alice: AccountId32 = dev::alice().public_key().into();
     let addr = node_runtime::storage().system().account(alice);
@@ -172,12 +170,11 @@ async fn chainhead_unstable_call() {
 
     let mut blocks = rpc.chainhead_unstable_follow(true).await.unwrap();
     let event = blocks.next().await.unwrap().unwrap();
-    let hashes = match event {
-        FollowEvent::Initialized(init) => init.finalized_block_hashes,
+    let hash = match event {
+        FollowEvent::Initialized(init) => init.finalized_block_hashes.last().unwrap().clone(),
         _ => panic!("Unexpected event"),
     };
     let sub_id = blocks.subscription_id().unwrap();
-    let hash = hashes[0];
 
     let alice_id = dev::alice().public_key().to_account_id();
     // Runtime API call.
@@ -210,12 +207,11 @@ async fn chainhead_unstable_unpin() {
 
     let mut blocks = rpc.chainhead_unstable_follow(true).await.unwrap();
     let event = blocks.next().await.unwrap().unwrap();
-    let hashes = match event {
-        FollowEvent::Initialized(init) => init.finalized_block_hashes,
+    let hash = match event {
+        FollowEvent::Initialized(init) => init.finalized_block_hashes.last().unwrap().clone(),
         _ => panic!("Unexpected event"),
     };
     let sub_id = blocks.subscription_id().unwrap();
-    let hash = hashes[0];
 
     assert!(rpc.chainhead_unstable_unpin(sub_id, hash).await.is_ok());
     // The block was already unpinned.