From a714ba6a90f44f1feba0e3ee4224908e761b5733 Mon Sep 17 00:00:00 2001
From: RunasSudo <runassudo@yingtongli.me>
Date: Wed, 9 Jun 2021 19:43:11 +1000
Subject: [PATCH] Correctly apportion votes in bulk exclusions

---
 src/stv/mod.rs | 31 ++++++++++++++++++-------------
 1 file changed, 18 insertions(+), 13 deletions(-)

diff --git a/src/stv/mod.rs b/src/stv/mod.rs
index e54358f..8cf09d5 100644
--- a/src/stv/mod.rs
+++ b/src/stv/mod.rs
@@ -964,6 +964,7 @@ where
 	// Determine votes to transfer in this stage
 	let mut votes = Vec::new();
 	let mut votes_remain;
+	let mut checksum = N::new();
 	
 	match opts.exclusion {
 		ExclusionMethod::SingleStage => {
@@ -972,6 +973,11 @@ where
 				let count_card = state.candidates.get_mut(excluded_candidate).unwrap();
 				votes.append(&mut count_card.parcels.concat());
 				//count_card.parcels.clear();
+				
+				// Update votes
+				let votes_transferred = votes.iter().fold(N::new(), |acc, v| acc + &v.value);
+				checksum -= &votes_transferred;
+				count_card.transfer(&-votes_transferred);
 			}
 			votes_remain = false;
 		}
@@ -993,8 +999,10 @@ where
 				
 				let cand_votes = count_card.parcels.concat();
 				
+				let mut votes_transferred = N::new();
 				for vote in cand_votes.into_iter() {
 					if &vote.value / &vote.ballot.orig_value == max_value {
+						votes_transferred += &vote.value;
 						votes.push(vote);
 					} else {
 						remaining_votes.push(vote);
@@ -1007,6 +1015,10 @@ where
 				
 				// Leave remaining votes with candidate (as one parcel)
 				count_card.parcels = vec![remaining_votes];
+				
+				// Update votes
+				checksum -= &votes_transferred;
+				count_card.transfer(&-votes_transferred);
 			}
 		}
 		ExclusionMethod::ParcelsByOrder => {
@@ -1018,11 +1030,14 @@ where
 			let count_card = state.candidates.get_mut(excluded_candidates.first().unwrap()).unwrap();
 			votes = count_card.parcels.remove(0);
 			votes_remain = count_card.parcels.len() > 0;
+			
+			// Update votes
+			let votes_transferred = votes.iter().fold(N::new(), |acc, v| acc + &v.value);
+			checksum -= &votes_transferred;
+			count_card.transfer(&-votes_transferred);
 		}
 	}
 	
-	let mut checksum = N::new();
-	
 	if votes.len() > 0 {
 		let value = &votes[0].value / &votes[0].ballot.orig_value;
 		
@@ -1060,16 +1075,6 @@ where
 		}
 		state.exhausted.transfer(&exhausted_transfers);
 		checksum += exhausted_transfers;
-		
-		if votes_remain {
-			if excluded_candidates.len() == 1 {
-				// TODO: Handle >1 excluded candidate
-				// Subtract from candidate tally
-				let count_card = state.candidates.get_mut(excluded_candidates.first().unwrap()).unwrap();
-				checksum -= &result.total_votes;
-				count_card.transfer(&-result.total_votes);
-			}
-		}
 	}
 	
 	if !votes_remain {
@@ -1077,7 +1082,7 @@ where
 		for excluded_candidate in excluded_candidates.into_iter() {
 			let count_card = state.candidates.get_mut(excluded_candidate).unwrap();
 			checksum -= &count_card.votes;
-			count_card.transfers = -count_card.votes.clone();
+			count_card.transfers -= &count_card.votes;
 			count_card.votes = N::new();
 		}