fix(schema): enable $ref resolution for directory charts

Set ChartDir only for directory-based charts to enable $ref resolution in
JSON schemas. Archived charts (.tgz) are loaded into memory without filesystem
extraction, so $ref resolution is not supported for them.

This fixes the original issue where `helm template .` and `helm install .`
failed to validate schemas with relative $ref references.

Fixes #31260

Signed-off-by: Benoit Tigeot <benoit.tigeot@lifen.fr>

pkg/cmd/install.go

@@ -248,6 +248,13 @@ func runInstall(args []string, client *action.Install, valueOpts *values.Options
 		return nil, err
 	}
 
+	// Only set ChartDir for directory-based charts to enable $ref resolution.
+	// Archived charts (.tgz) are loaded into memory without filesystem extraction,
+	// so $ref resolution is not supported for them.
+	if fi, err := os.Stat(cp); err == nil && fi.IsDir() {
+		client.ChartDir = cp
+	}
+
 	slog.Debug("Chart path", "path", cp)
 
 	p := getter.All(settings)

pkg/cmd/install_test.go

@@ -231,6 +231,11 @@ func TestInstall(t *testing.T) {
 			cmd:    "install schema testdata/testcharts/chart-with-schema-and-subchart --set lastname=doe --set subchart-with-schema.age=-25 --skip-schema-validation",
 			golden: "output/schema.txt",
 		},
+		{
+			name:   "install with schema file containing $ref",
+			cmd:    "install reftest testdata/testcharts/chart-with-schema-ref",
+			golden: "output/schema-ref.txt",
+		},
 		// Install deprecated chart
 		{
 			name:   "install with warning about deprecated chart",

pkg/cmd/template_test.go

@@ -166,6 +166,11 @@ func TestTemplateCmd(t *testing.T) {
 			cmd:    fmt.Sprintf("template '%s' -f %s/extra_values.yaml", chartPath, chartPath),
 			golden: "output/template-subchart-cm-set-file.txt",
 		},
+		{
+			name:   "template with schema file containing $ref",
+			cmd:    "template reftest testdata/testcharts/chart-with-schema-ref",
+			golden: "output/template-schema-ref.txt",
+		},
 	}
 	runTestCmd(t, tests)
 }

pkg/cmd/testdata/output/schema-ref.txt

@@ -0,0 +1,7 @@
+NAME: reftest
+LAST DEPLOYED: Fri Sep  2 22:04:05 1977
+NAMESPACE: default
+STATUS: deployed
+REVISION: 1
+DESCRIPTION: Install complete
+TEST SUITE: None

pkg/cmd/testdata/output/template-schema-ref.txt

@@ -0,0 +1 @@
+

pkg/cmd/testdata/output/upgrade-schema-ref.txt

@@ -0,0 +1,8 @@
+Release "reftest" has been upgraded. Happy Helming!
+NAME: reftest
+LAST DEPLOYED: Fri Sep  2 22:04:05 1977
+NAMESPACE: default
+STATUS: deployed
+REVISION: 2
+DESCRIPTION: Upgrade complete
+TEST SUITE: None

pkg/cmd/testdata/testcharts/chart-with-schema-ref/Chart.yaml

@@ -0,0 +1,3 @@
+apiVersion: v2
+name: chart-with-schema-ref
+version: 0.1.0

pkg/cmd/testdata/testcharts/chart-with-schema-ref/name.schema.json

@@ -0,0 +1,4 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "type": "string"
+}

pkg/cmd/testdata/testcharts/chart-with-schema-ref/values.schema.json

@@ -0,0 +1,7 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "type": "object",
+  "properties": {
+    "name": { "$ref": "name.schema.json" }
+  }
+}

pkg/cmd/testdata/testcharts/chart-with-schema-ref/values.yaml

@@ -0,0 +1 @@
+name: "test"

pkg/cmd/upgrade.go

@@ -187,6 +187,13 @@ func newUpgradeCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 				return err
 			}
 
+			// Only set ChartDir for directory-based charts to enable $ref resolution.
+			// Archived charts (.tgz) are loaded into memory without filesystem extraction,
+			// so $ref resolution is not supported for them.
+			if fi, err := os.Stat(chartPath); err == nil && fi.IsDir() {
+				client.ChartDir = chartPath
+			}
+
 			p := getter.All(settings)
 			vals, err := valueOpts.MergeValues(p)
 			if err != nil {

pkg/cmd/upgrade_test.go

@@ -190,6 +190,12 @@ func TestUpgradeCmd(t *testing.T) {
 			golden: "output/upgrade-uninstalled-with-keep-history.txt",
 			rels:   []*release.Release{relWithStatusMock("funny-bunny", 2, ch, rcommon.StatusUninstalled)},
 		},
+		{
+			name:   "upgrade with schema file containing $ref",
+			cmd:    "upgrade reftest testdata/testcharts/chart-with-schema-ref",
+			golden: "output/upgrade-schema-ref.txt",
+			rels:   []*release.Release{relMock("reftest", 1, ch)},
+		},
 	}
 	runTestCmd(t, tests)
 }