kube-gen: cut off conversion-gen from k8s.io/apimachinery

staging/src/k8s.io/kube-gen/cmd/conversion-gen/generators/conversion.go

@@ -24,7 +24,6 @@ import (
 	"sort"
 	"strings"
 
-	"k8s.io/apimachinery/pkg/util/sets"
 	"k8s.io/gengo/args"
 	"k8s.io/gengo/generator"
 	"k8s.io/gengo/namer"
@@ -188,7 +187,6 @@ func Packages(context *generator.Context, arguments *args.GeneratorArgs) generat
 		glog.Fatalf("Failed loading boilerplate: %v", err)
 	}
 
-	inputs := sets.NewString(context.Inputs...)
 	packages := generator.Packages{}
 	header := append([]byte(fmt.Sprintf("// +build !%s\n\n", arguments.GeneratedBuildTag)), boilerplate...)
 	header = append(header, []byte("\n// This file was autogenerated by conversion-gen. Do not edit it manually!\n\n")...)
@@ -207,7 +205,14 @@ func Packages(context *generator.Context, arguments *args.GeneratorArgs) generat
 
 	// We are generating conversions only for packages that are explicitly
 	// passed as InputDir.
-	for i := range inputs {
+	processed := map[string]bool{}
+	for _, i := range context.Inputs {
+		// skip duplicates
+		if processed[i] {
+			continue
+		}
+		processed[i] = true
+
 		glog.V(5).Infof("considering pkg %q", i)
 		pkg := context.Universe[i]
 		// typesPkg is where the versioned types are defined. Sometimes it is