From f4e7cb7fa9bd7cf4c1faafc8645d346a5e768699 Mon Sep 17 00:00:00 2001
From: Doordashcon <jesse.chejieh@gmail.com>
Date: Mon, 15 Sep 2025 09:33:06 +0100
Subject: [PATCH] Simulate `rank_to_votes` in `pallet-ranked-collective`
 benchmark. (#9731)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

resolves #9730

---------

Co-authored-by: Bastian Köcher <info@kchr.de>
Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
(cherry picked from commit 1cbf4eed97a87ae4c1aef6176c80761c49f60e6f)
---
 prdoc/pr_9731.prdoc                           | 14 +++++++++++
 .../ranked-collective/src/benchmarking.rs     | 23 +++++++++++++++----
 2 files changed, 33 insertions(+), 4 deletions(-)
 create mode 100644 prdoc/pr_9731.prdoc

diff --git a/prdoc/pr_9731.prdoc b/prdoc/pr_9731.prdoc
new file mode 100644
index 0000000000000..5ce5576d95fcc
--- /dev/null
+++ b/prdoc/pr_9731.prdoc
@@ -0,0 +1,14 @@
+title: simulate `rank_to_votes` conversion in vote benchmark
+
+doc:
+- audience: Runtime Dev
+  description: |
+    Fixes benchmarking failures for the vote extrinsic in pallet-ranked-collective by properly
+    simulating the `rank_to_votes` conversion process. Previously used hardcoded vote values
+    which caused assertion failures when using custom VoteWeight converters (e.g., in
+    [Ambassador Collective configuration](https://github.com/polkadot-fellows/runtimes/pull/736)). The fix calculates vote weight based on member's
+    actual rank and minimum required rank for the class.
+
+crates:
+- name: pallet-ranked-collective
+  bump: patch
\ No newline at end of file
diff --git a/substrate/frame/ranked-collective/src/benchmarking.rs b/substrate/frame/ranked-collective/src/benchmarking.rs
index 978489fb8485e..68f0623ac910f 100644
--- a/substrate/frame/ranked-collective/src/benchmarking.rs
+++ b/substrate/frame/ranked-collective/src/benchmarking.rs
@@ -58,7 +58,9 @@ fn make_member<T: Config<I>, I: 'static>(rank: Rank) -> T::AccountId {
 }
 
 #[instance_benchmarks(
-where <<T as pallet::Config<I>>::Polls as frame_support::traits::Polling<Tally<T, I, pallet::Pallet<T, I>>>>::Index: From<u8>
+where
+	<<T as pallet::Config<I>>::Polls as frame_support::traits::Polling<Tally<T, I, pallet::Pallet<T, I>>>>::Index: From<u8>,
+	<T as frame_system::Config>::RuntimeEvent: TryInto<pallet::Event<T, I>>,
 )]
 mod benchmarks {
 	use super::*;
@@ -227,9 +229,22 @@ mod benchmarks {
 
 		// If the class exists, verify the vote event and tally.
 		if let Some(_) = class {
-			let tally = Tally::from_parts(0, 0, 1);
-			let vote_event = Event::Voted { who: caller, poll, vote: VoteRecord::Nay(1), tally };
-			assert_last_event::<T, I>(vote_event.into());
+			// Get the actual vote weight from the latest event's VoteRecord::Nay
+			let mut events = frame_system::Pallet::<T>::events();
+			let last_event = events.pop().expect("At least one event should exist");
+			let event: Event<T, I> = last_event
+				.event
+				.try_into()
+				.unwrap_or_else(|_| panic!("Event conversion failed"));
+
+			match event {
+				Event::Voted { vote: VoteRecord::Nay(vote_weight), who, poll: poll2, tally } => {
+					assert_eq!(tally, Tally::from_parts(0, 0, vote_weight));
+					assert_eq!(caller, who);
+					assert_eq!(poll, poll2);
+				},
+				_ => panic!("Invalid event"),
+			};
 		}
 
 		Ok(())