Fix deep merge of ValuesYamlFiles (#2963)

Stop relying on `yaml.Unmarshal` to merge `ValuesYaml` as it cannot do a
deep merge. Instead we Unmarshal the values in a temporary map and use
the `mergeMap` function that already exists to merge.

With this the behavior of the provider is aligned with the deep merge
made by Helm helm/helm#1620

Fixes #2958 .

---------

Co-authored-by: Bryce Lampe <bryce@pulumi.com>

CHANGELOG.md

@@ -1,5 +1,7 @@
 ## Unreleased
 
+- Fix Release behavior to deep merge `valueYamlFiles` to match Helm. (https://github.com/pulumi/pulumi-kubernetes/pull/2963)
+
 ## 4.11.0 (April 17, 2024)
 
 - [dotnet] Unknowns for previews involving an uninitialized provider (https://github.com/pulumi/pulumi-kubernetes/pull/2957)

provider/pkg/helm/upstream.go

@@ -0,0 +1,38 @@
+/*
+Copyright The Helm Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// package helm contains code vendored from the upstream Helm project.
+package helm
+
+// https://github.com/helm/helm/blob/14d0c13e9eefff5b4a1b511cf50643529692ec94/pkg/cli/values/options.go#L108-L125
+func MergeMaps(a, b map[string]interface{}) map[string]interface{} {
+	out := make(map[string]interface{}, len(a))
+	for k, v := range a {
+		out[k] = v
+	}
+	for k, v := range b {
+		if v, ok := v.(map[string]interface{}); ok {
+			if bv, ok := out[k]; ok {
+				if bv, ok := bv.(map[string]interface{}); ok {
+					out[k] = MergeMaps(bv, v)
+					continue
+				}
+			}
+		}
+		out[k] = v
+	}
+	return out
+}

provider/pkg/provider/helm_release.go

@@ -32,6 +32,7 @@ import (
 	"github.com/mitchellh/mapstructure"
 	pkgerrors "github.com/pkg/errors"
 	"github.com/pulumi/pulumi-kubernetes/provider/v4/pkg/clients"
+	"github.com/pulumi/pulumi-kubernetes/provider/v4/pkg/helm"
 	"github.com/pulumi/pulumi-kubernetes/provider/v4/pkg/host"
 	"github.com/pulumi/pulumi/sdk/v3/go/common/diag"
 	"github.com/pulumi/pulumi/sdk/v3/go/common/resource"
@@ -299,9 +300,11 @@ func decodeRelease(pm resource.PropertyMap, label string) (*Release, error) {
 					if err != nil {
 						return nil, err
 					}
-					if err = yaml.Unmarshal(b, &values); err != nil {
+					valuesMap := map[string]any{}
+					if err = yaml.Unmarshal(b, &valuesMap); err != nil {
 						return nil, err
 					}
+					values = helm.MergeMaps(values, valuesMap)
 				default:
 					return nil, fmt.Errorf("unsupported type for 'valueYamlFiles' arg: %T", v)
 				}

provider/pkg/provider/helm_release_test.go

@@ -17,6 +17,8 @@ package provider
 import (
 	"testing"
 
+	"github.com/pulumi/pulumi/sdk/v3/go/common/resource"
+	"github.com/pulumi/pulumi/sdk/v3/go/common/resource/asset"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -138,3 +140,115 @@ func Test_MergeMaps(t *testing.T) {
 		})
 	}
 }
+
+func TestDecodeRelease(t *testing.T) {
+	bitnamiImage := `
+image:
+  repository: bitnami/nginx
+  tag: latest
+`
+
+	tests := []struct {
+		name  string
+		given resource.PropertyMap
+		want  *Release
+	}{
+		{
+			name: "valueYamlFiles layering",
+			given: resource.PropertyMap{
+				"valueYamlFiles": resource.NewArrayProperty([]resource.PropertyValue{
+					resource.NewAssetProperty(&asset.Asset{Text: `
+image:
+  repository: bitnami/nginx
+`}),
+					resource.NewAssetProperty(&asset.Asset{Text: `
+image:
+  tag: "1.25.0"
+`}),
+				}),
+			},
+			want: &Release{
+				Values: map[string]any{
+					"image": map[string]any{
+						"tag":        "1.25.0",
+						"repository": "bitnami/nginx",
+					},
+				},
+			},
+		},
+		{
+			name: "valueYamlFiles with literals",
+			given: resource.PropertyMap{
+				"values": resource.NewObjectProperty(resource.PropertyMap{
+					"image": resource.NewObjectProperty(resource.PropertyMap{
+						"tag": resource.NewStringProperty("patched"),
+					}),
+				},
+				),
+				"valueYamlFiles": resource.NewArrayProperty([]resource.PropertyValue{
+					resource.NewAssetProperty(&asset.Asset{Text: bitnamiImage}),
+				}),
+			},
+			want: &Release{
+				Values: map[string]any{
+					"image": map[string]any{
+						"repository": "bitnami/nginx",
+						"tag":        "patched",
+					},
+				},
+			},
+		},
+		{
+			name: "valueYamlFiles with literals and allowNullValues=true",
+			given: resource.PropertyMap{
+				"allowNullValues": resource.NewBoolProperty(true),
+				"values": resource.NewObjectProperty(resource.PropertyMap{
+					"image": resource.NewObjectProperty(resource.PropertyMap{
+						"tag": resource.NewNullProperty(),
+					}),
+				},
+				),
+				"valueYamlFiles": resource.NewArrayProperty([]resource.PropertyValue{
+					resource.NewAssetProperty(&asset.Asset{Text: bitnamiImage}),
+				}),
+			},
+			want: &Release{
+				AllowNullValues: true,
+				Values: map[string]any{
+					"image": map[string]any{
+						"repository": "bitnami/nginx",
+						"tag":        nil,
+					},
+				},
+			},
+		},
+		{
+			name: "valueYamlFiles with literals and allowNullValues=false",
+			given: resource.PropertyMap{
+				"values": resource.NewObjectProperty(resource.PropertyMap{
+					"image": resource.NewObjectProperty(resource.PropertyMap{
+						"tag": resource.NewNullProperty(),
+					}),
+				},
+				),
+				"valueYamlFiles": resource.NewArrayProperty([]resource.PropertyValue{
+					resource.NewAssetProperty(&asset.Asset{Text: bitnamiImage}),
+				}),
+			},
+			want: &Release{
+				Values: map[string]any{
+					"image": map[string]any{
+						"repository": "bitnami/nginx",
+						"tag":        "latest", // Not removed.
+					},
+				},
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		actual, err := decodeRelease(tt.given, "")
+		assert.NoError(t, err)
+		assert.Equal(t, tt.want, actual)
+	}
+}