From 6c3b2f686ec09857b6a09486e08806757b71a0ab Mon Sep 17 00:00:00 2001
From: Ryan Uber <ru@ryanuber.com>
Date: Tue, 22 Apr 2014 23:33:30 -0700
Subject: [PATCH] snapshot: FilterLatestRefs returns nothing as it deals with a
 pointer.

---
 cmd/snapshot_merge.go |  2 +-
 deb/reflist.go        | 10 +++++-----
 deb/reflist_test.go   |  6 +++---
 3 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/cmd/snapshot_merge.go b/cmd/snapshot_merge.go
index b7e85656..96ab10ac 100644
--- a/cmd/snapshot_merge.go
+++ b/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))
diff --git a/deb/reflist.go b/deb/reflist.go
index a6eb85cf..27636a5c 100644
--- a/deb/reflist.go
+++ b/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.
-// This implements a "latest wins" approach which can be used while merging two
-// or more snapshots together.
-func FilterLatestRefs(r *PackageRefList) *PackageRefList {
+// packages and reduces it to only the latest of each package. The operations
+// are done in-place. This implements a "latest wins" approach which can be used
+// while merging two or more snapshots together.
+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
 }
diff --git a/deb/reflist_test.go b/deb/reflist_test.go
index c6fc867d..12ef2711 100644
--- a/deb/reflist_test.go
+++ b/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)
-	merged := FilterLatestRefs(prl)
+	result := NewPackageRefListFromPackageList(rl)
+	FilterLatestRefs(result)
 
-	c.Check(toStrSlice(merged), DeepEquals,
+	c.Check(toStrSlice(result), DeepEquals,
 		[]string{"Pi386 dpkg 1.6", "Pi386 lib 1.2"})
 }