Repository: helm/helm (go)

Issue:
RFE: Support for multi-document values files
Helm support providing multiple values files. Unfortunately, only first YAML document of each file is taken into consideration.

As many values files (i.e. document) are supported, there's no functional reason to not support one values file with many documents. Documents in a single values file should be considered if they were split into many files and just passed in order.

To be more precise giving:

* `A.yaml`

```yaml
---
# A-1.yaml
---
# A-2.yaml
````

* `B.yaml`

```yaml
---
# B-1.yaml
---
# B-2.yaml
````

implies these two equivalent:

* `helm template my-release my-chart -f A.yaml -f B.yaml`
* `helm template my-release my-chart -f A-1.yaml -f A-2.yaml -f B-1.yaml -f B-2.yaml`


Pull request description:
feat: support multi-document values files
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**What this PR does / why we need it**:
close #13097 
**Special notes for your reviewer**:



Patch:
diff --git a/pkg/chart/loader/load.go b/pkg/chart/loader/load.go
index 7645ba96c..e32094ef5 100644
--- a/pkg/chart/loader/load.go
+++ b/pkg/chart/loader/load.go
@@ -17,14 +17,17 @@ limitations under the License.
 package loader
 
 import (
+	"bufio"
 	"bytes"
 	"encoding/json"
+	"io"
 	"log"
 	"os"
 	"path/filepath"
 	"strings"
 
 	"github.com/pkg/errors"
+	utilyaml "k8s.io/apimachinery/pkg/util/yaml"
 	"sigs.k8s.io/yaml"
 
 	"helm.sh/helm/v4/pkg/chart"
@@ -104,13 +107,11 @@ func LoadFiles(files []*BufferedFile) (*chart.Chart, error) {
 				return c, errors.Wrap(err, "cannot load Chart.lock")
 			}
 		case f.Name == "values.yaml":
-			c.Values = make(map[string]interface{})
-			if err := yaml.Unmarshal(f.Data, &c.Values, func(d *json.Decoder) *json.Decoder {
-				d.UseNumber()
-				return d
-			}); err != nil {
+			values, err := LoadValues(bytes.NewReader(f.Data))
+			if err != nil {
 				return c, errors.Wrap(err, "cannot load values.yaml")
 			}
+			c.Values = values
 		case f.Name == "values.schema.json":
 			c.Schema = f.Data
 
@@ -205,3 +206,51 @@ func LoadFiles(files []*BufferedFile) (*chart.Chart, error) {
 
 	return c, nil
 }
+
+// LoadValues loads values from a reader.
+//
+// The reader is expected to contain one or more YAML documents, the values of which are merged.
+// And the values can be either a chart's default values or a user-supplied values.
+func LoadValues(data io.Reader) (map[string]interface{}, error) {
+	values := map[string]interface{}{}
+	reader := utilyaml.NewYAMLReader(bufio.NewReader(data))
+	for {
+		currentMap := map[string]interface{}{}
+		raw, err := reader.Read()
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return nil, errors.Wrap(err, "error reading yaml document")
+		}
+		if err := yaml.Unmarshal(raw, &currentMap, func(d *json.Decoder) *json.Decoder {
+			d.UseNumber()
+			return d
+		}); err != nil {
+			return nil, errors.Wrap(err, "cannot unmarshal yaml document")
+		}
+		values = MergeMaps(values, currentMap)
+	}
+	return values, nil
+}
+
+// MergeMaps merges two maps. If a key exists in both maps, the value from b will be used.
+// If the value is a map, the maps will be merged recursively.
+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
+}
diff --git a/pkg/cli/values/options.go b/pkg/cli/values/options.go
index add2f72d5..2c3706b84 100644
--- a/pkg/cli/values/options.go
+++ b/pkg/cli/values/options.go
@@ -17,6 +17,7 @@ limitations under the License.
 package values
 
 import (
+	"bytes"
 	"encoding/json"
 	"io"
 	"net/url"
@@ -24,8 +25,8 @@ import (
 	"strings"
 
 	"github.com/pkg/errors"
-	"sigs.k8s.io/yaml"
 
+	"helm.sh/helm/v4/pkg/chart/loader"
 	"helm.sh/helm/v4/pkg/getter"
 	"helm.sh/helm/v4/pkg/strvals"
 )
@@ -47,18 +48,16 @@ func (opts *Options) MergeValues(p getter.Providers) (map[string]interface{}, er
 
 	// User specified a values files via -f/--values
 	for _, filePath := range opts.ValueFiles {
-		currentMap := map[string]interface{}{}
-
-		bytes, err := readFile(filePath, p)
+		raw, err := readFile(filePath, p)
 		if err != nil {
 			return nil, err
 		}
-
-		if err := yaml.Unmarshal(bytes, &currentMap); err != nil {
+		currentMap, err := loader.LoadValues(bytes.NewReader(raw))
+		if err != nil {
 			return nil, errors.Wrapf(err, "failed to parse %s", filePath)
 		}
 		// Merge with the previous map
-		base = mergeMaps(base, currentMap)
+		base = loader.MergeMaps(base, currentMap)
 	}
 
 	// User specified a value via --set-json
@@ -70,7 +69,7 @@ func (opts *Options) MergeValues(p getter.Providers) (map[string]interface{}, er
 			if err := json.Unmarshal([]byte(trimmedValue), &jsonMap); err != nil {
 				return nil, errors.Errorf("failed parsing --set-json data JSON: %s", value)
 			}
-			base = mergeMaps(base, jsonMap)
+			base = loader.MergeMaps(base, jsonMap)
 		} else {
 			// Otherwise, parse it as key=value format
 			if err := strvals.ParseJSON(value, base); err != nil {
@@ -117,25 +116,6 @@ func (opts *Options) MergeValues(p getter.Providers) (map[string]interface{}, er
 	return base, nil
 }
 
-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
-}
-
 // readFile load a file from stdin, the local directory, or a remote file with a url.
 func readFile(filePath string, p getter.Providers) ([]byte, error) {
 	if strings.TrimSpace(filePath) == "-" {


Test patch:
diff --git a/pkg/chart/loader/load_test.go b/pkg/chart/loader/load_test.go
index 25e000835..e34124829 100644
--- a/pkg/chart/loader/load_test.go
+++ b/pkg/chart/loader/load_test.go
@@ -24,6 +24,7 @@ import (
 	"log"
 	"os"
 	"path/filepath"
+	"reflect"
 	"runtime"
 	"strings"
 	"testing"
@@ -488,6 +489,115 @@ func TestLoadInvalidArchive(t *testing.T) {
 	}
 }
 
+func TestLoadValues(t *testing.T) {
+	testCases := map[string]struct {
+		data          []byte
+		expctedValues map[string]interface{}
+	}{
+		"It should load values correctly": {
+			data: []byte(`
+foo:
+  image: foo:v1
+bar:
+  version: v2
+`),
+			expctedValues: map[string]interface{}{
+				"foo": map[string]interface{}{
+					"image": "foo:v1",
+				},
+				"bar": map[string]interface{}{
+					"version": "v2",
+				},
+			},
+		},
+		"It should load values correctly with multiple documents in one file": {
+			data: []byte(`
+foo:
+  image: foo:v1
+bar:
+  version: v2
+---
+foo:
+  image: foo:v2
+`),
+			expctedValues: map[string]interface{}{
+				"foo": map[string]interface{}{
+					"image": "foo:v2",
+				},
+				"bar": map[string]interface{}{
+					"version": "v2",
+				},
+			},
+		},
+	}
+	for testName, testCase := range testCases {
+		t.Run(testName, func(tt *testing.T) {
+			values, err := LoadValues(bytes.NewReader(testCase.data))
+			if err != nil {
+				tt.Fatal(err)
+			}
+			if !reflect.DeepEqual(values, testCase.expctedValues) {
+				tt.Errorf("Expected values: %v, got %v", testCase.expctedValues, values)
+			}
+		})
+	}
+}
+
+func TestMergeValues(t *testing.T) {
+	nestedMap := map[string]interface{}{
+		"foo": "bar",
+		"baz": map[string]string{
+			"cool": "stuff",
+		},
+	}
+	anotherNestedMap := map[string]interface{}{
+		"foo": "bar",
+		"baz": map[string]string{
+			"cool":    "things",
+			"awesome": "stuff",
+		},
+	}
+	flatMap := map[string]interface{}{
+		"foo": "bar",
+		"baz": "stuff",
+	}
+	anotherFlatMap := map[string]interface{}{
+		"testing": "fun",
+	}
+
+	testMap := MergeMaps(flatMap, nestedMap)
+	equal := reflect.DeepEqual(testMap, nestedMap)
+	if !equal {
+		t.Errorf("Expected a nested map to overwrite a flat value. Expected: %v, got %v", nestedMap, testMap)
+	}
+
+	testMap = MergeMaps(nestedMap, flatMap)
+	equal = reflect.DeepEqual(testMap, flatMap)
+	if !equal {
+		t.Errorf("Expected a flat value to overwrite a map. Expected: %v, got %v", flatMap, testMap)
+	}
+
+	testMap = MergeMaps(nestedMap, anotherNestedMap)
+	equal = reflect.DeepEqual(testMap, anotherNestedMap)
+	if !equal {
+		t.Errorf("Expected a nested map to overwrite another nested map. Expected: %v, got %v", anotherNestedMap, testMap)
+	}
+
+	testMap = MergeMaps(anotherFlatMap, anotherNestedMap)
+	expectedMap := map[string]interface{}{
+		"testing": "fun",
+		"foo":     "bar",
+		"baz": map[string]string{
+			"cool":    "things",
+			"awesome": "stuff",
+		},
+	}
+	equal = reflect.DeepEqual(testMap, expectedMap)
+	if !equal {
+		t.Errorf("Expected a map with different keys to merge properly with another map. Expected: %v, got %v", expectedMap, testMap)
+	}
+}
+
 func verifyChart(t *testing.T, c *chart.Chart) {
 	t.Helper()
 	if c.Name() == "" {
diff --git a/pkg/cli/values/options_test.go b/pkg/cli/values/options_test.go
index 5197a1b5e..c3bb0af33 100644
--- a/pkg/cli/values/options_test.go
+++ b/pkg/cli/values/options_test.go
@@ -23,61 +23,6 @@ import (
 	"helm.sh/helm/v4/pkg/getter"
 )
 
-func TestMergeMaps(t *testing.T) {
-	nestedMap := map[string]interface{}{
-		"foo": "bar",
-		"baz": map[string]string{
-			"cool": "stuff",
-		},
-	}
-	anotherNestedMap := map[string]interface{}{
-		"foo": "bar",
-		"baz": map[string]string{
-			"cool":    "things",
-			"awesome": "stuff",
-		},
-	}
-	flatMap := map[string]interface{}{
-		"foo": "bar",
-		"baz": "stuff",
-	}
-	anotherFlatMap := map[string]interface{}{
-		"testing": "fun",
-	}
-
-	testMap := mergeMaps(flatMap, nestedMap)
-	equal := reflect.DeepEqual(testMap, nestedMap)
-	if !equal {
-		t.Errorf("Expected a nested map to overwrite a flat value. Expected: %v, got %v", nestedMap, testMap)
-	}
-
-	testMap = mergeMaps(nestedMap, flatMap)
-	equal = reflect.DeepEqual(testMap, flatMap)
-	if !equal {
-		t.Errorf("Expected a flat value to overwrite a map. Expected: %v, got %v", flatMap, testMap)
-	}
-
-	testMap = mergeMaps(nestedMap, anotherNestedMap)
-	equal = reflect.DeepEqual(testMap, anotherNestedMap)
-	if !equal {
-		t.Errorf("Expected a nested map to overwrite another nested map. Expected: %v, got %v", anotherNestedMap, testMap)
-	}
-
-	testMap = mergeMaps(anotherFlatMap, anotherNestedMap)
-	expectedMap := map[string]interface{}{
-		"testing": "fun",
-		"foo":     "bar",
-		"baz": map[string]string{
-			"cool":    "things",
-			"awesome": "stuff",
-		},
-	}
-	equal = reflect.DeepEqual(testMap, expectedMap)
-	if !equal {
-		t.Errorf("Expected a map with different keys to merge properly with another map. Expected: %v, got %v", expectedMap, testMap)
-	}
-}
-
 func TestReadFile(t *testing.T) {
 	var p getter.Providers
 	filePath := "%a.txt"