fix(action): preserve YAML list documents through post-render roundtrip

Signed-off-by: vigneshakaviki <kumarvignesh295@gmail.com>

pkg/action/action.go

@@ -204,16 +204,14 @@ func annotateAndMerge(files map[string]string) (string, error) {
 			if strings.TrimSpace(doc) == "" {
 				continue
 			}
-			manifests, err := kio.ParseAll(doc)
+			manifest, err := kyaml.Parse(doc)
 			if err != nil {
 				return "", fmt.Errorf("parsing %s: %w", fname, err)
 			}
-			for _, manifest := range manifests {
-				if err := manifest.PipeE(kyaml.SetAnnotation(filenameAnnotation, fname)); err != nil {
-					return "", fmt.Errorf("annotating %s: %w", fname, err)
-				}
-				combinedManifests = append(combinedManifests, manifest)
+			if err := manifest.PipeE(kyaml.SetAnnotation(filenameAnnotation, fname)); err != nil {
+				return "", fmt.Errorf("annotating %s: %w", fname, err)
 			}
+			combinedManifests = append(combinedManifests, manifest)
 		}
 	}
 
@@ -234,13 +232,13 @@ func annotateAndMerge(files map[string]string) (string, error) {
 // group), so that merging results from different invocations does not collide
 // on the same synthetic key.
 func splitAndDeannotate(postrendered, fallbackPrefix string) (map[string]string, error) {
-	manifests, err := kio.ParseAll(postrendered)
-	if err != nil {
-		return nil, fmt.Errorf("error parsing YAML: %w", err)
-	}
-
+	docs := releaseutil.SplitManifests(postrendered)
 	manifestsByFilename := make(map[string][]*kyaml.RNode)
-	for i, manifest := range manifests {
+	for i := 0; i < len(docs); i++ {
+		manifest, err := kyaml.Parse(docs[fmt.Sprintf("manifest-%d", i)])
+		if err != nil {
+			return nil, fmt.Errorf("error parsing YAML: %w", err)
+		}
 		meta, err := manifest.GetMeta()
 		if err != nil {
 			return nil, fmt.Errorf("getting metadata: %w", err)

pkg/action/action_test.go

@@ -1704,7 +1704,7 @@ data:
 		{
 			name:          "invalid yaml input",
 			input:         "invalid: yaml: content:",
-			expectedError: "error parsing YAML: MalformedYAMLError",
+			expectedError: "error parsing YAML:",
 		},
 		{
 			name: "manifest without filename annotation",
@@ -1799,6 +1799,33 @@ data:
 	}
 }
 
+func TestRenderResources_PostRenderer_ListAnchorRoundTrip(t *testing.T) {
+	cfg := actionConfigFixture(t)
+	ch := buildChartWithTemplates([]*common.File{{
+		Name:    "templates/list.yaml",
+		ModTime: time.Now(),
+		Data: []byte(`apiVersion: v1
+kind: List
+items:
+- apiVersion: v1
+  kind: ConfigMap
+  metadata:
+    name: cm-a
+  data: &shared
+    key: value
+- apiVersion: v1
+  kind: ConfigMap
+  metadata:
+    name: cm-b
+  data: *shared`),
+	}})
+
+	_, buf, _, err := cfg.renderResources(t.Context(), ch, nil, "test-release", "", false, false, false, &mockPostRenderer{}, false, false, false, PostRenderStrategyCombined)
+	require.NoError(t, err)
+	assert.Contains(t, buf.String(), "name: cm-a")
+	assert.Contains(t, buf.String(), "name: cm-b")
+}
+
 func TestRenderResources_PostRenderer_Success(t *testing.T) {
 	cfg := actionConfigFixture(t)
 
@@ -1915,7 +1942,7 @@ func TestRenderResources_PostRenderer_SplitError(t *testing.T) {
 		mockPR, false, false, false, PostRenderStrategyCombined,
 	)
 
-	assert.ErrorContains(t, err, "error while parsing post rendered output: error parsing YAML: MalformedYAMLError:")
+	assert.ErrorContains(t, err, "error while parsing post rendered output: error parsing YAML:")
 }
 
 func TestRenderResources_PostRenderer_Integration(t *testing.T) {