test(create): Test to check deprecated resource templates

Test to check deprecation warnings on resource templates that are
created by `helm create` against the latest Kubernetes version. This
test is run in a separate Makefile command to avoid failing other unit
tests configured to run with a specific Kubernetes version(s).

For resources that are disabled by default (like hpa and ingress),
to avoid skipping them from the helm linter test, they are enabled in
the test.

Fixes #11495

Signed-off-by: Bhargav Ravuri <bhargav.ravuri@infracloud.io>

Makefile

@@ -105,6 +105,15 @@ test-unit:
 	@echo
 	@echo "==> Running unit tests <=="
 	GO111MODULE=on go test $(GOFLAGS) -run $(TESTS) $(PKG) $(TESTFLAGS)
+	@echo
+	@echo "==> Running unit test(s) with ldflags <=="
+# Test to check the deprecation warnings on Kubernetes templates created by `helm create` against the current Kubernetes
+# version. Note: The version details are set in var LDFLAGS. To avoid the ldflags impact on other unit tests that are
+# based on older versions, this is run separately. When run without the ldflags in the unit test (above) or coverage
+# test, it still passes with a false-positive result as the resources shouldn’t be deprecated in the older Kubernetes
+# version if it only starts failing with the latest. 
+	GO111MODULE=on go test $(GOFLAGS) -run ^TestHelmCreateChart_CheckDeprecatedWarnings$$ ./pkg/lint/ $(TESTFLAGS) -ldflags '$(LDFLAGS)'
+
 
 .PHONY: test-coverage
 test-coverage:

pkg/chartutil/create.go

@@ -622,6 +622,10 @@ func Create(name, dir string) (string, error) {
 		return cdir, errors.Errorf("file %s already exists and is not a directory", cdir)
 	}
 
+	// Note: If adding a new template below (i.e., to `helm create`) which is disabled by default (similar to hpa and
+	// ingress below); or making an existing template disabled by default, add the enabling condition in
+	// `TestHelmCreateChart_CheckDeprecatedWarnings` in `pkg/lint/lint_test.go` to make it run through deprecation checks
+	// with latest Kubernetes version.
 	files := []struct {
 		path    string
 		content []byte

pkg/lint/lint_test.go

@@ -137,6 +137,53 @@ func TestHelmCreateChart(t *testing.T) {
 	}
 }
 
+// TestHelmCreateChart_CheckDeprecatedWarnings checks if any default template created by `helm create` throws
+// deprecated warnings in the linter check against the current Kubernetes version (provided using ldflags).
+//
+// See https://github.com/helm/helm/issues/11495
+//
+// Resources like hpa and ingress, which are disabled by default in values.yaml are enabled here using the equivalent
+// of the `--set` flag.
+//
+// Note: This test requires the following ldflags to be set per the current Kubernetes version to avoid false-positive
+// results.
+// 1. -X helm.sh/helm/v3/pkg/lint/rules.k8sVersionMajor=<k8s-major-version>
+// 2. -X helm.sh/helm/v3/pkg/lint/rules.k8sVersionMinor=<k8s-minor-version>
+// or directly use '$(LDFLAGS)' in Makefile.
+//
+// When run without ldflags, the test passes giving a false-positive result. This is because the variables
+// `k8sVersionMajor` and `k8sVersionMinor` by default are set to an older version of Kubernetes, with which, there
+// might not be the deprecation warning.
+func TestHelmCreateChart_CheckDeprecatedWarnings(t *testing.T) {
+	createdChart, err := chartutil.Create("checkdeprecatedwarnings", t.TempDir())
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	// Add values to enable hpa, and ingress which are disabled by default.
+	// This is the equivalent of:
+	//   helm lint checkdeprecatedwarnings --set 'autoscaling.enabled=true,ingress.enabled=true'
+	updatedValues := map[string]interface{}{
+		"autoscaling": map[string]interface{}{
+			"enabled": true,
+		},
+		"ingress": map[string]interface{}{
+			"enabled": true,
+		},
+	}
+
+	linterRunDetails := All(createdChart, updatedValues, namespace, true)
+	for _, msg := range linterRunDetails.Messages {
+		if strings.HasPrefix(msg.Error(), "[WARNING]") &&
+			strings.Contains(msg.Error(), "deprecated") {
+			// When there is a deprecation warning for an object created
+			// by `helm create` for the current Kubernetes version, fail.
+			t.Errorf("Unexpected deprecation warning for %q: %s", msg.Path, msg.Error())
+		}
+	}
+}
+
 // lint ignores import-values
 // See https://github.com/helm/helm/issues/9658
 func TestSubChartValuesChart(t *testing.T) {