Return a lint warning if `templates/` does not exist.

Signed-off-by: Zach Burgess <zachburg@google.com>

pkg/action/lint_test.go

@@ -154,12 +154,12 @@ func TestLint_ChartWithWarnings(t *testing.T) {
 		}
 	})
 
-	t.Run("should pass with no errors when strict", func(t *testing.T) {
+	t.Run("should fail with one error when strict", func(t *testing.T) {
 		testCharts := []string{chartWithNoTemplatesDir}
 		testLint := NewLint()
 		testLint.Strict = true
-		if result := testLint.Run(testCharts, values); len(result.Errors) != 0 {
-			t.Error("expected no errors, but got", len(result.Errors))
+		if result := testLint.Run(testCharts, values); len(result.Errors) != 1 {
+			t.Error("expected one error, but got", len(result.Errors))
 		}
 	})
 }

pkg/cmd/testdata/output/lint-chart-with-bad-subcharts-with-subcharts.txt

@@ -1,5 +1,6 @@
 ==> Linting testdata/testcharts/chart-with-bad-subcharts
 [INFO] Chart.yaml: icon is recommended
+[WARNING] templates/: directory does not exist
 [ERROR] : unable to load chart
 	error unpacking subchart bad-subchart in chart-with-bad-subcharts: validation: chart.metadata.name is required
 
@@ -8,10 +9,12 @@
 [ERROR] Chart.yaml: apiVersion is required. The value must be either "v1" or "v2"
 [ERROR] Chart.yaml: version is required
 [INFO] Chart.yaml: icon is recommended
+[WARNING] templates/: directory does not exist
 [ERROR] : unable to load chart
 	validation: chart.metadata.name is required
 
 ==> Linting testdata/testcharts/chart-with-bad-subcharts/charts/good-subchart
 [INFO] Chart.yaml: icon is recommended
+[WARNING] templates/: directory does not exist
 
 Error: 3 chart(s) linted, 2 chart(s) failed

pkg/cmd/testdata/output/lint-chart-with-bad-subcharts.txt

@@ -1,5 +1,6 @@
 ==> Linting testdata/testcharts/chart-with-bad-subcharts
 [INFO] Chart.yaml: icon is recommended
+[WARNING] templates/: directory does not exist
 [ERROR] : unable to load chart
 	error unpacking subchart bad-subchart in chart-with-bad-subcharts: validation: chart.metadata.name is required
 

pkg/cmd/testdata/output/lint-quiet-with-error.txt

@@ -1,6 +1,7 @@
 ==> Linting testdata/testcharts/chart-bad-requirements
 [ERROR] Chart.yaml: unable to parse YAML
 	error converting YAML to JSON: yaml: line 6: did not find expected '-' indicator
+[WARNING] templates/: directory does not exist
 [ERROR] : unable to load chart
 	cannot load Chart.yaml: error converting YAML to JSON: yaml: line 6: did not find expected '-' indicator
 

pkg/cmd/testdata/output/lint-quiet-with-warning.txt

@@ -0,0 +1,4 @@
+==> Linting testdata/testcharts/chart-with-only-crds
+[WARNING] templates/: directory does not exist
+
+1 chart(s) linted, 0 chart(s) failed

pkg/lint/rules/template.go

@@ -55,7 +55,8 @@ func TemplatesWithSkipSchemaValidation(linter *support.Linter, values map[string
 	templatesPath := filepath.Join(linter.ChartDir, fpath)
 
 	// Templates directory is optional for now
-	if _, err := os.Stat(templatesPath); errors.Is(err, os.ErrNotExist) {
+	templatesDirExists := linter.RunLinterRule(support.WarningSev, fpath, templatesDirExists(templatesPath))
+	if !templatesDirExists {
 		return
 	}
 
@@ -197,6 +198,14 @@ func validateTopIndentLevel(content string) error {
 }
 
 // Validation functions
+func templatesDirExists(templatesPath string) error {
+	_, err := os.Stat(templatesPath)
+	if errors.Is(err, os.ErrNotExist) {
+		return errors.New("directory does not exist")
+	}
+	return nil
+}
+
 func validateTemplatesDir(templatesPath string) error {
 	fi, err := os.Stat(templatesPath)
 	if err != nil {