Fix regression 4388

kyaml/resid/gvk.go

@@ -97,6 +97,29 @@ func (x Gvk) String() string {
 	return strings.Join([]string{k, v, g}, fieldSep)
 }
 
+// legacySortString returns an older version of String() that LegacyOrderTransformer depends on
+// to keep its ordering stable across Kustomize versions
+func (x Gvk) legacySortString() string {
+	legacyNoGroup := "~G"
+	legacyNoVersion := "~V"
+	legacyNoKind := "~K"
+	legacyFieldSeparator := "_"
+
+	g := x.Group
+	if g == "" {
+		g = legacyNoGroup
+	}
+	v := x.Version
+	if v == "" {
+		v = legacyNoVersion
+	}
+	k := x.Kind
+	if k == "" {
+		k = legacyNoKind
+	}
+	return strings.Join([]string{g, v, k}, legacyFieldSeparator)
+}
+
 // ApiVersion returns the combination of Group and Version
 func (x Gvk) ApiVersion() string {
 	var sb strings.Builder
@@ -180,7 +203,7 @@ func (x Gvk) IsLessThan(o Gvk) bool {
 	if indexI != indexJ {
 		return indexI < indexJ
 	}
-	return x.String() < o.String()
+	return x.legacySortString() < o.legacySortString()
 }
 
 // IsSelected returns true if `selector` selects `x`; otherwise, false.

kyaml/resid/gvk_test.go

@@ -47,8 +47,8 @@ var lessThanTests = []struct {
 		Gvk{Group: "a", Version: "c", Kind: "ClusterRole"}},
 	{Gvk{Group: "a", Version: "c", Kind: "Namespace"},
 		Gvk{Group: "a", Version: "b", Kind: "ClusterRole"}},
-	{Gvk{Group: "b", Version: "c", Kind: "Namespace"},
-		Gvk{Group: "a", Version: "d", Kind: "Namespace"}},
+	{Gvk{Group: "a", Version: "d", Kind: "Namespace"},
+		Gvk{Group: "b", Version: "c", Kind: "Namespace"}},
 	{Gvk{Group: "a", Version: "b", Kind: orderFirst[len(orderFirst)-1]},
 		Gvk{Group: "a", Version: "b", Kind: orderLast[0]}},
 	{Gvk{Group: "a", Version: "b", Kind: orderFirst[len(orderFirst)-1]},

kyaml/resid/resid.go

@@ -60,6 +60,25 @@ func (id ResId) String() string {
 		[]string{id.Gvk.String(), strings.Join([]string{nm, ns}, fieldSep)}, separator)
 }
 
+// LegacySortString returns an older version of String() that LegacyOrderTransformer depends on
+// to keep its ordering stable across Kustomize versions
+func (id ResId) LegacySortString() string {
+	legacyNoNamespace := "~X"
+	legacyNoName := "~N"
+	legacySeparator := "|"
+
+	ns := id.Namespace
+	if ns == "" {
+		ns = legacyNoNamespace
+	}
+	nm := id.Name
+	if nm == "" {
+		nm = legacyNoName
+	}
+	return strings.Join(
+		[]string{id.Gvk.String(), ns, nm}, legacySeparator)
+}
+
 func FromString(s string) ResId {
 	values := strings.Split(s, separator)
 	gvk := GvkFromString(values[0])