commitment: Fix off-by-one affecting even-sized clusters

Guaderxx · Mar 21, 2016 · 163a55f · 163a55f
1 parent 259e54d
commit 163a55f
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Showing 2 changed files with 2 additions and 2 deletions.
diff --git a/commitment.go b/commitment.go
@@ -91,7 +91,7 @@ func (c *commitment) recalculate() {
 			matched = append(matched, idx)
 		}
 		sort.Sort(uint64Slice(matched))
-		quorumMatchIndex = matched[len(c.matchIndexes)/2]
+		quorumMatchIndex = matched[(len(matched)-1)/2]
 	}
 	if quorumMatchIndex > c.commitIndex && quorumMatchIndex >= c.startIndex {
 		c.commitIndex = quorumMatchIndex

diff --git a/commitment_test.go b/commitment_test.go
@@ -9,7 +9,7 @@ func voters(n int) []string {
 	if n > 7 {
 		panic("only up to 7 servers implemented")
 	}
-	return []string{"s1", "s2", "s3", "s4", "s5", "s6", "s7"}[:n+1]
+	return []string{"s1", "s2", "s3", "s4", "s5", "s6", "s7"}[:n]
 }
 
 // Tests setVoters() keeps matchIndexes where possible.