Add copy method to VarSet

pkg/accumulator/resaccumulator.go

@@ -39,7 +39,7 @@ func (ra *ResAccumulator) ResMap() resmap.ResMap {
 
 // Vars returns a copy of underlying vars.
 func (ra *ResAccumulator) Vars() []types.Var {
-	return ra.varSet.Set()
+	return ra.varSet.AsSlice()
 }
 
 func (ra *ResAccumulator) AppendAll(
@@ -75,7 +75,7 @@ func (ra *ResAccumulator) MergeAccumulator(other *ResAccumulator) (err error) {
 	if err != nil {
 		return err
 	}
-	return ra.varSet.MergeSet(&other.varSet)
+	return ra.varSet.MergeSet(other.varSet)
 }
 
 // makeVarReplacementMap returns a map of Var names to

pkg/types/var.go

@@ -75,15 +75,20 @@ type VarSet struct {
 	set []Var
 }
 
-// Set returns a copy of the var set.
-func (vs *VarSet) Set() []Var {
+// AsSlice returns the vars as a slice.
+func (vs *VarSet) AsSlice() []Var {
 	s := make([]Var, len(vs.set))
 	copy(s, vs.set)
 	return s
 }
 
+// Copy returns a copy of the var set.
+func (vs *VarSet) Copy() VarSet {
+	return VarSet{set: vs.AsSlice()}
+}
+
 // MergeSet absorbs other vars with error on name collision.
-func (vs *VarSet) MergeSet(incoming *VarSet) error {
+func (vs *VarSet) MergeSet(incoming VarSet) error {
 	return vs.MergeSlice(incoming.set)
 }
 

pkg/types/var_test.go

@@ -89,7 +89,7 @@ func TestDefaulting(t *testing.T) {
 }
 
 func TestVarSet(t *testing.T) {
-	set := &VarSet{}
+	set := VarSet{}
 	vars := []Var{
 		{
 			Name: "SHELLVARS",
@@ -120,10 +120,10 @@ func TestVarSet(t *testing.T) {
 	}
 	for _, v := range vars {
 		if !set.Contains(v) {
-			t.Fatalf("set %v should contain var %v", set.Set(), v)
+			t.Fatalf("set %v should contain var %v", set.AsSlice(), v)
 		}
 	}
-	set2 := &VarSet{}
+	set2 := VarSet{}
 	err = set2.MergeSet(set)
 	if err != nil {
 		t.Fatalf("unexpected err: %v", err)
@@ -144,7 +144,7 @@ func TestVarSet(t *testing.T) {
 		t.Fatalf("unexpected field path: %v", v.FieldRef.FieldPath)
 	}
 	// Confirm sorting.
-	names := set2.Set()
+	names := set2.AsSlice()
 	if names[0].Name != "AWARD" ||
 		names[1].Name != "BACKEND" ||
 		names[2].Name != "SHELLVARS" {