Update handling chart dependencies on helm dep update

Do not exit the Update function when there are no dependencies

Add unit test to verify removing dependencies when they are removed from chart

Signed-off-by: Lucas Rodriguez <lucas.rodriguez9616@gmail.com>

cmd/helm/dependency_update_test.go

@@ -206,6 +206,77 @@ func TestDependencyUpdateCmd_DoNotDeleteOldChartsOnError(t *testing.T) {
 	}
 }
 
+/*
+TestDependencyUpdateCmd_RemoveChartDepsWhenDepsRemoved tests for the case when a chart previously had dependencies
+defined, and they were later removed, that helm dep update properly removes/cleanses those dependencies from the charts/ directory,
+which also verifies that the lock file was updated properly because dependencies from the lockfile are written to the charts/ directory.
+*/
+func TestDependencyUpdateCmd_RemoveChartDepsWhenDepsRemoved(t *testing.T) {
+	defer resetEnv()()
+	defer ensure.HelmHome(t)()
+
+	srv, err := repotest.NewTempServerWithCleanup(t, "testdata/testcharts/*.tgz")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer srv.Stop()
+	t.Logf("Listening on directory %s", srv.Root())
+
+	if err := srv.LinkIndices(); err != nil {
+		t.Fatal(err)
+	}
+
+	dir := func(p ...string) string {
+		return filepath.Join(append([]string{srv.Root()}, p...)...)
+	}
+
+	// Create chart with dependencies.
+	chartname := "depup"
+	ch := createTestingMetadata(chartname, srv.URL())
+	if err := chartutil.SaveDir(ch, dir()); err != nil {
+		t.Fatal(err)
+	}
+
+	// Run dep update to store chart dependencies in charts/ dir.
+	_, output, err := executeActionCommand(fmt.Sprintf("dependency update %s --repository-config %s --repository-cache %s", dir(chartname), dir("repositories.yaml"), dir()))
+	if err != nil {
+		t.Logf("Output: %s", output)
+		t.Fatal(err)
+	}
+
+	// Update chart to remove dependencies.
+	ch = createTestingMetadataWithNoDeps(chartname, srv.URL())
+	if err := chartutil.SaveDir(ch, dir()); err != nil {
+		t.Fatal(err)
+	}
+
+	// Run dep update to remove chart dependencies from charts/ dir.
+	_, output, err = executeActionCommand(fmt.Sprintf("dependency update %s --repository-config %s --repository-cache %s", dir(chartname), dir("repositories.yaml"), dir()))
+	if err != nil {
+		t.Logf("Output: %s", output)
+		t.Fatal(err)
+	}
+
+	// Chart repo is down.
+	srv.Stop()
+
+	// Get chart dependencies from charts/ dir. There shouldn't be any after the last update.
+	deps, err := os.ReadDir(filepath.Join(dir(chartname), "charts"))
+	if err != nil {
+		t.Fatal("Failed to get dependencies from charts/ dir")
+	}
+
+	// Make sure charts/ dir has no dependencies.
+	if len(deps) != 0 {
+		t.Fatalf("Expected 0 chart dependencies, got %d", len(deps))
+	}
+
+	// Make sure tmpcharts is deleted.
+	if _, err := os.Stat(filepath.Join(dir(chartname), "tmpcharts")); !os.IsNotExist(err) {
+		t.Fatalf("tmpcharts dir still exists")
+	}
+}
+
 // createTestingMetadata creates a basic chart that depends on reqtest-0.1.0
 //
 // The baseURL can be used to point to a particular repository server.
@@ -223,6 +294,19 @@ func createTestingMetadata(name, baseURL string) *chart.Chart {
 	}
 }
 
+// createTestingMetadataWithNoDeps creates a basic chart with no dependencies
+//
+// The baseURL can be used to point to a particular repository server.
+func createTestingMetadataWithNoDeps(name, baseURL string) *chart.Chart {
+	return &chart.Chart{
+		Metadata: &chart.Metadata{
+			APIVersion: chart.APIVersionV2,
+			Name:       name,
+			Version:    "1.2.3",
+		},
+	}
+}
+
 func createTestingMetadataForOCI(name, registryURL string) *chart.Chart {
 	return &chart.Chart{
 		Metadata: &chart.Metadata{

pkg/downloader/manager.go

@@ -155,11 +155,11 @@ func (m *Manager) Update() error {
 		return err
 	}
 
-	// If no dependencies are found, we consider this a successful
-	// completion.
 	req := c.Metadata.Dependencies
-	if req == nil {
-		return nil
+	// The nil check determines whether the 'dependencies:' key exists in a Chart.yaml.
+	// The len(chartDeps) < 1 check determines whether the 'dependencies' key is empty in a Chart.yaml.
+	if req == nil || len(req) < 1 {
+		fmt.Fprintln(m.Out, "No chart dependencies found")
 	}
 
 	// Get the names of the repositories the dependencies need that Helm is