fix(api/types): map HelmChartArgs.ReleaseNamespace -> HelmChart.Namespace

SplitHelmParameters goes through makeHelmChartFromHca to translate
the deprecated HelmChartArgs into the current HelmChart type. That
mapping forgot to copy ReleaseNamespace onto Namespace, so kustomiz-
ations that used the deprecated helmChartInflationGenerator field
with releaseNamespace silently rendered every resource into the
default namespace instead of the requested one.

HelmChartArgs is documented as deprecated, but kustomize still
supports it, and the rendering bug is visible: users follow the docs
for releaseNamespace and get a kustomization that emits the wrong
namespace with no warning.

The fix is one line — copy ReleaseNamespace onto Namespace in
makeHelmChartFromHca — plus a regression test under
TestSplitHelmParametersPropagatesReleaseNamespace that pins the
mapping so the bug cannot silently regress.

Fixes #4593

Signed-off-by: Sai Asish Y <say.apm35@gmail.com>

Author: SAY-5

api/types/helmchartargs.go

@@ -148,6 +148,11 @@ func makeHelmChartFromHca(old *HelmChartArgs) (c HelmChart) {
 	c.ValuesInline = old.ValuesLocal
 	c.ValuesMerge = old.ValuesMerge
 	c.ReleaseName = old.ReleaseName
+	// ReleaseNamespace maps onto Namespace in the (non-deprecated)
+	// HelmChart type. Forgetting this mapping is why releaseNamespace
+	// set under the deprecated helmChartInflationGenerator field is
+	// silently ignored — see kubernetes-sigs/kustomize#4593.
+	c.Namespace = old.ReleaseNamespace
 	return
 }
 

api/types/helmchartargs_test.go

@@ -102,3 +102,23 @@ func TestAsHelmArgs(t *testing.T) {
 				"--devel"})
 	})
 }
+
+// Regression test for https://github.com/kubernetes-sigs/kustomize/issues/4593.
+// HelmChartArgs.ReleaseNamespace was not copied into HelmChart.Namespace by
+// makeHelmChartFromHca, so kustomizations that used the deprecated
+// helmChartInflationGenerator with releaseNamespace silently rendered resources
+// into the "default" namespace.
+func TestSplitHelmParametersPropagatesReleaseNamespace(t *testing.T) {
+	args := []types.HelmChartArgs{{
+		ChartName:        "nats",
+		ChartVersion:     "v0.13.1",
+		ReleaseName:      "nats",
+		ReleaseNamespace: "custom-ns",
+	}}
+
+	charts, _ := types.SplitHelmParameters(args)
+
+	require.Len(t, charts, 1)
+	require.Equal(t, "custom-ns", charts[0].Namespace,
+		"ReleaseNamespace from the deprecated HelmChartArgs must map onto HelmChart.Namespace")
+}