From c9ff0a16fb40343f688ed0524d2848a7d47e20ec Mon Sep 17 00:00:00 2001
From: RunasSudo <runassudo@yingtongli.me>
Date: Sun, 27 Dec 2020 23:30:54 +1100
Subject: [PATCH] Fix error/bug when excluding candidates in exclusive Gregory

---
 html/worker.js           |  1 +
 pyRCV2/method/parcels.py | 71 ++++++++++++++++++++--------------------
 2 files changed, 37 insertions(+), 35 deletions(-)

diff --git a/html/worker.js b/html/worker.js
index ef23dae..3959d0a 100644
--- a/html/worker.js
+++ b/html/worker.js
@@ -104,6 +104,7 @@ function stepElection() {
 				postMessage({'type': 'require_input', 'message': ex.message});
 				break;
 			} else {
+				console.error(ex);
 				throw ex;
 			}
 		}
diff --git a/pyRCV2/method/parcels.py b/pyRCV2/method/parcels.py
index dc4f7e8..acab4c4 100644
--- a/pyRCV2/method/parcels.py
+++ b/pyRCV2/method/parcels.py
@@ -127,50 +127,51 @@ class ParcelledEGSTVCounter(UIGSTVCounter):
 		next_preferences = SafeDict([(c, []) for c, cc in self.candidates.items()])
 		next_exhausted = []
 		
-		parcel = count_card.parcels[0]
-		count_card.parcels.remove(parcel)
-		
-		# Count next preferences
-		for ballot, ballot_value in parcel:
-			__pragma__('opov')
-			candidate = next((c for c in ballot.preferences if self.candidates[c].state == CandidateState.HOPEFUL), None)
-			__pragma__('noopov')
+		if len(count_card.parcels) > 0:
+			parcel = count_card.parcels[0]
+			count_card.parcels.remove(parcel)
 			
-			if candidate is not None:
+			# Count next preferences
+			for ballot, ballot_value in parcel:
 				__pragma__('opov')
-				next_preferences[candidate].append((ballot, ballot_value))
+				candidate = next((c for c in ballot.preferences if self.candidates[c].state == CandidateState.HOPEFUL), None)
 				__pragma__('noopov')
-			else:
-				next_exhausted.append((ballot, ballot_value))
-		
-		# Make transfers
-		for candidate, cand_ballots in next_preferences.items():
-			if len(cand_ballots) == 0:
-				continue
+				
+				if candidate is not None:
+					__pragma__('opov')
+					next_preferences[candidate].append((ballot, ballot_value))
+					__pragma__('noopov')
+				else:
+					next_exhausted.append((ballot, ballot_value))
 			
-			new_parcel = []
-			__pragma__('opov')
-			self.candidates[candidate].parcels.append(new_parcel)
-			__pragma__('noopov')
+			# Make transfers
+			for candidate, cand_ballots in next_preferences.items():
+				if len(cand_ballots) == 0:
+					continue
+				
+				new_parcel = []
+				__pragma__('opov')
+				self.candidates[candidate].parcels.append(new_parcel)
+				__pragma__('noopov')
+				
+				num_votes = sum((bv for b, bv in cand_ballots), Rational('0'))
+				__pragma__('opov')
+				self.candidates[candidate].transfers += num_votes.to_num()
+				count_card.transfers -= num_votes.to_num()
+				__pragma__('noopov')
+				
+				for ballot, ballot_value in cand_ballots:
+					new_parcel.append((ballot, ballot_value))
 			
-			num_votes = sum((bv for b, bv in cand_ballots), Rational('0'))
+			# Credit exhausted votes
+			num_votes = sum((bv for b, bv in next_exhausted), Rational('0'))
 			__pragma__('opov')
-			self.candidates[candidate].transfers += num_votes.to_num()
+			self.exhausted.transfers += num_votes.to_num()
 			count_card.transfers -= num_votes.to_num()
 			__pragma__('noopov')
 			
-			for ballot, ballot_value in cand_ballots:
-				new_parcel.append((ballot, ballot_value))
-		
-		# Credit exhausted votes
-		num_votes = sum((bv for b, bv in next_exhausted), Rational('0'))
-		__pragma__('opov')
-		self.exhausted.transfers += num_votes.to_num()
-		count_card.transfers -= num_votes.to_num()
-		__pragma__('noopov')
-		
-		for ballot, ballot_value in next_exhausted:
-			self.exhausted.ballots.append((ballot, ballot_value))
+			for ballot, ballot_value in next_exhausted:
+				self.exhausted.ballots.append((ballot, ballot_value))
 		
 		if len(count_card.parcels) == 0:
 			count_card.state = CandidateState.EXCLUDED