snapshot: FilterLatestRefs returns nothing as it deals with a pointer.

cmd/snapshot_merge.go

@@ -38,7 +38,7 @@ func aptlySnapshotMerge(cmd *commander.Command, args []string) error {
 	}
 
 	if latest {
-		result = deb.FilterLatestRefs(result)
+		deb.FilterLatestRefs(result)
 	}
 
 	sourceDescription := make([]string, len(sources))

deb/reflist.go

@@ -286,10 +286,10 @@ func (l *PackageRefList) Merge(r *PackageRefList, overrideMatching bool) (result
 }
 
 // FilterLatestRefs takes in a reflist with potentially multiples of the same
-// packages and returns a reflist containing only the latest of each package.
+// packages and reduces it to only the latest of each package. The operations
-// This implements a "latest wins" approach which can be used while merging two
+// are done in-place. This implements a "latest wins" approach which can be used
-// or more snapshots together.
+// while merging two or more snapshots together.
-func FilterLatestRefs(r *PackageRefList) *PackageRefList {
+func FilterLatestRefs(r *PackageRefList) {
 	// A running tab of latest seen package refs.
 	latestRefs := make(map[string]int)
 
@@ -322,5 +322,5 @@ func FilterLatestRefs(r *PackageRefList) *PackageRefList {
 		i -= 1
 	}
 
-	return r
+	return
 }

deb/reflist_test.go

@@ -304,9 +304,9 @@ func (s *PackageRefListSuite) TestFilterLatestRefs(c *C) {
 	rl.Add(packages[7])
 	rl.Add(packages[7])
 
-	prl := NewPackageRefListFromPackageList(rl)
+	result := NewPackageRefListFromPackageList(rl)
-	merged := FilterLatestRefs(prl)
+	FilterLatestRefs(result)
 
-	c.Check(toStrSlice(merged), DeepEquals,
+	c.Check(toStrSlice(result), DeepEquals,
 		[]string{"Pi386 dpkg 1.6", "Pi386 lib 1.2"})
 }