Use goccy/go-yaml for v1 / Prep bringing back go-yaml v2 for v0.x (#604)

This is a successor to #596. We need a smooth migration path from `gopkg.in/yaml.v2`, and this pull request moves it forward with `goccy/go-yaml` instead of `gopkg.in/yaml.v3`. Merging this unblocks users stuck in Helmfile v0.146.x or earlier due to #435, so that they can upgrade to 0.147.x or greater without updating their helmfile configs.

We previously tried to upgrade to `yaml.v3` (https://github.com/helmfile/helmfile/issues/394) in Helmfile v0.x, presuming it won't break anything. Apparently, it broke use-cases where you want to layer release's `values` field over three or more release templates and releases (#435).

We then tried to bring back `yaml.v2` for Helmfile v0.x and keep `yaml.v3` for the upcoming Helmfile v1. However, it failed due to incompatibility in the Unmarshaller interface between `yaml.v2` and `yaml.v3` (https://github.com/helmfile/helmfile/pull/596).

`goccy/go-yaml` is, from my observation, a well-maintained alternative to `yaml.v2`. One of its premises is that it enables us to swap the implementation from `gopkg.in/yaml.v2` to `goccy/go-yaml` just by replacing the import directive. It seems to use the same `Unmarshaller` interface as yaml.v2 too.

Once this PR gets merged, I'd like to follow-up with adding a new build-time variable and an envvar to set the proper default for the yaml parser Helmfile uses and the ability to switch the parser at runtime. All in all, the next Helmfile release, v0.150.0 will get reverted to use `gopkg.in/yaml.v2` by default which resolves #435.

New users who started using Helmfile since any of v0.148.0, v0.148.1, and v0.149.0 might be already relying on the new behavior, They might need to specify a new envvar to enable `goccy/go-yaml`.

Signed-off-by: yxxhero <aiopsclub@163.com>
Signed-off-by: yxxhero <aiopsclub@163.com>
Co-authored-by: yxxhero <aiopsclub@163.com>

go.mod

@@ -8,6 +8,7 @@ require (
 	github.com/aryann/difflib v0.0.0-20170710044230-e206f873d14a
 	github.com/davecgh/go-spew v1.1.1
 	github.com/go-test/deep v1.1.0
+	github.com/goccy/go-yaml v1.9.8
 	github.com/golang/mock v1.6.0
 	github.com/google/go-cmp v0.5.9
 	github.com/gosuri/uitable v0.0.4
@@ -27,7 +28,7 @@ require (
 	go.uber.org/zap v1.24.0
 	golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4
 	golang.org/x/term v0.3.0
-	gopkg.in/yaml.v3 v3.0.1
+	gopkg.in/yaml.v2 v2.4.0
 	helm.sh/helm/v3 v3.10.3
 	k8s.io/apimachinery v0.26.0
 )
@@ -163,7 +164,6 @@ require (
 	github.com/go-openapi/jsonpointer v0.19.5 // indirect
 	github.com/go-openapi/jsonreference v0.19.5 // indirect
 	github.com/go-openapi/swag v0.19.14 // indirect
-	github.com/goccy/go-yaml v1.9.5 // indirect
 	github.com/gogo/protobuf v1.3.2 // indirect
 	github.com/google/btree v1.0.1 // indirect
 	github.com/google/gnostic v0.5.7-v3refs // indirect
@@ -206,7 +206,7 @@ require (
 	go.starlark.net v0.0.0-20200306205701-8dd3e2ee1dd5 // indirect
 	golang.org/x/crypto v0.3.0 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect
-	gopkg.in/yaml.v2 v2.4.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 	k8s.io/api v0.25.2 // indirect
 	k8s.io/cli-runtime v0.25.2 // indirect
 	k8s.io/client-go v0.25.2 // indirect

go.sum

@@ -322,15 +322,18 @@ github.com/go-openapi/swag v0.19.5/go.mod h1:POnQmlKehdgb5mhVOsnJFsivZCEZ/vjK9gh
 github.com/go-openapi/swag v0.19.14 h1:gm3vOOXfiuw5i9p5N9xJvfjvuofpyvLA9Wr6QfK5Fng=
 github.com/go-openapi/swag v0.19.14/go.mod h1:QYRuS/SOXUCsnplDa677K7+DxSOj6IPNl/eQntq43wQ=
 github.com/go-playground/assert/v2 v2.0.1/go.mod h1:VDjEfimB/XKnb+ZQfWdccd7VUvScMdVu0Titje2rxJ4=
+github.com/go-playground/locales v0.13.0 h1:HyWk6mgj5qFqCT5fjGBuRArbVDfE4hi8+e8ceBS/t7Q=
 github.com/go-playground/locales v0.13.0/go.mod h1:taPMhCMXrRLJO55olJkUXHZBHCxTMfnGwq/HNwmWNS8=
+github.com/go-playground/universal-translator v0.17.0 h1:icxd5fm+REJzpZx7ZfpaD876Lmtgy7VtROAbHHXk8no=
 github.com/go-playground/universal-translator v0.17.0/go.mod h1:UkSxE5sNxxRwHyU+Scu5vgOQjsIJAF8j9muTVoKLVtA=
+github.com/go-playground/validator/v10 v10.4.1 h1:pH2c5ADXtd66mxoE0Zm9SUhxE20r7aM3F26W0hOn+GE=
 github.com/go-playground/validator/v10 v10.4.1/go.mod h1:nlOn6nFhuKACm19sB/8EGNn9GlaMV7XkbRSipzJ0Ii4=
 github.com/go-stack/stack v1.8.0/go.mod h1:v0f6uXyyMGvRgIKkXu+yp6POWl0qKG85gN/melR3HDY=
 github.com/go-test/deep v1.0.2-0.20181118220953-042da051cf31/go.mod h1:wGDj63lr65AM2AQyKZd/NYHGb0R+1RLqB8NKt3aSFNA=
 github.com/go-test/deep v1.1.0 h1:WOcxcdHcvdgThNXjw0t76K42FXTU7HpNQWHpA2HHNlg=
 github.com/go-test/deep v1.1.0/go.mod h1:5C2ZWiW0ErCdrYzpqxLbTX7MG14M9iiw8DgHncVwcsE=
-github.com/goccy/go-yaml v1.9.5 h1:Eh/+3uk9kLxG4koCX6lRMAPS1OaMSAi+FJcya0INdB0=
-github.com/goccy/go-yaml v1.9.5/go.mod h1:U/jl18uSupI5rdI2jmuCswEA2htH9eXfferR3KfscvA=
+github.com/goccy/go-yaml v1.9.8 h1:5gMyLUeU1/6zl+WFfR1hN7D2kf+1/eRGa7DFtToiBvQ=
+github.com/goccy/go-yaml v1.9.8/go.mod h1:JubOolP3gh0HpiBc4BLRD4YmjEjHAmIIB2aaXKkTfoE=
 github.com/gogo/protobuf v1.1.1/go.mod h1:r8qH/GZQm5c6nD/R0oafs1akxWv10x8SbQlK7atdtwQ=
 github.com/gogo/protobuf v1.2.0/go.mod h1:r8qH/GZQm5c6nD/R0oafs1akxWv10x8SbQlK7atdtwQ=
 github.com/gogo/protobuf v1.3.2 h1:Ov1cvc58UF3b5XjBnZv7+opcTcQFZebYjWzi34vdm4Q=
@@ -582,6 +585,7 @@ github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
 github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0SNc=
 github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
+github.com/leodido/go-urn v1.2.0 h1:hpXL4XnriNwQ/ABnpepYM/1vCLWNDfUNts8dX3xTG6Y=
 github.com/leodido/go-urn v1.2.0/go.mod h1:+8+nEpDfqqsY+g338gtMEUOtuK+4dEMhiQEgxpxOKII=
 github.com/lestrrat-go/envload v0.0.0-20180220234015-a3eb8ddeffcc h1:RKf14vYWi2ttpEmkA4aQ3j4u9dStX2t4M8UM6qqNsG8=
 github.com/lestrrat-go/envload v0.0.0-20180220234015-a3eb8ddeffcc/go.mod h1:kopuH9ugFRkIXf3YoqHKyrJ9YfUFsckUU9S7B+XP+is=
@@ -1064,6 +1068,7 @@ golang.org/x/sys v0.0.0-20220128215802-99c3d69c2c27/go.mod h1:oPkhp1MJrh7nUepCBc
 golang.org/x/sys v0.0.0-20220209214540-3681064d5158/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220227234510-4e6760a101f9/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220328115105-d36c6a25d886/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220406163625-3f8b81556e12/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220412211240-33da011f77ad/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220502124256-b6088ccd6cba/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220503163025-988cb79eb6c6/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=

pkg/app/app_list_test.go

@@ -242,7 +242,7 @@ environments:
 releases:
 - name: myrelease1
   chart: mychart1
-  installed: no
+  installed: false
   labels:
     id: myrelease1
 - name: myrelease2
@@ -253,7 +253,7 @@ releases:
 releases:
 - name: myrelease3
   chart: mychart1
-  installed: yes
+  installed: true
 - name: myrelease4
   chart: mychart1
   labels:

pkg/app/app_template_test.go

@@ -16,6 +16,7 @@ import (
 	ffs "github.com/helmfile/helmfile/pkg/filesystem"
 	"github.com/helmfile/helmfile/pkg/helmexec"
 	"github.com/helmfile/helmfile/pkg/testhelper"
+	"github.com/helmfile/helmfile/pkg/yaml"
 )
 
 func TestTemplate(t *testing.T) {
@@ -306,3 +307,88 @@ releases:
 		})
 	})
 }
+
+func TestTemplate_StrictParsing(t *testing.T) {
+	v := yaml.GoccyGoYaml
+	yaml.GoccyGoYaml = true
+	t.Cleanup(func() {
+		yaml.GoccyGoYaml = v
+	})
+
+	type testcase struct {
+		ns    string
+		error string
+	}
+
+	check := func(t *testing.T, tc testcase) {
+		t.Helper()
+
+		var helm = &exectest.Helm{
+			FailOnUnexpectedList: true,
+			FailOnUnexpectedDiff: true,
+			DiffMutex:            &sync.Mutex{},
+			ChartsMutex:          &sync.Mutex{},
+			ReleasesMutex:        &sync.Mutex{},
+		}
+
+		_ = runWithLogCapture(t, "debug", func(t *testing.T, logger *zap.SugaredLogger) {
+			t.Helper()
+
+			valsRuntime, err := vals.New(vals.Options{CacheSize: 32})
+			if err != nil {
+				t.Errorf("unexpected error creating vals runtime: %v", err)
+			}
+
+			files := map[string]string{
+				"/path/to/helmfile.yaml": `
+releases:
+- name: app1
+  foobar: FOOBAR
+  chart: incubator/raw
+`,
+			}
+
+			app := appWithFs(&App{
+				OverrideHelmBinary:  DefaultHelmBinary,
+				fs:                  &ffs.FileSystem{Glob: filepath.Glob},
+				OverrideKubeContext: "default",
+				Env:                 "default",
+				Logger:              logger,
+				helms: map[helmKey]helmexec.Interface{
+					createHelmKey("helm", "default"): helm,
+				},
+				valsRuntime: valsRuntime,
+			}, files)
+
+			if tc.ns != "" {
+				app.Namespace = tc.ns
+			}
+
+			tmplErr := app.Template(applyConfig{
+				// if we check log output, concurrency must be 1. otherwise the test becomes non-deterministic.
+				concurrency: 1,
+				logger:      logger,
+			})
+
+			var gotErr string
+			if tmplErr != nil {
+				gotErr = tmplErr.Error()
+			}
+
+			if d := cmp.Diff(tc.error, gotErr); d != "" {
+				t.Fatalf("unexpected error: want (-), got (+): %s", d)
+			}
+		})
+	}
+
+	t.Run("fail due to known field", func(t *testing.T) {
+		check(t, testcase{
+			error: `in ./helmfile.yaml: failed to read helmfile.yaml: reading document at index 1: [4:3] unknown field "foobar"
+       2 | releases:
+       3 | - name: app1
+    >  4 |   foobar: FOOBAR
+             ^
+       5 |   chart: incubator/raw`,
+		})
+	})
+}

pkg/app/app_test.go

@@ -4288,7 +4288,7 @@ environments:
 releases:
 - name: myrelease1
   chart: mychart1
-  installed: no
+  installed: false
   labels:
     id: myrelease1
 - name: myrelease2
@@ -4299,7 +4299,7 @@ releases:
 releases:
 - name: myrelease3
   chart: mychart1
-  installed: yes
+  installed: true
 - name: myrelease4
   chart: mychart1
   labels:

pkg/app/load_opts.go

@@ -1,10 +1,8 @@
 package app
 
 import (
-	"gopkg.in/yaml.v3"
-
-	"github.com/helmfile/helmfile/pkg/maputil"
 	"github.com/helmfile/helmfile/pkg/state"
+	"github.com/helmfile/helmfile/pkg/yaml"
 )
 
 type LoadOpts struct {
@@ -22,7 +20,7 @@ type LoadOpts struct {
 }
 
 func (o LoadOpts) DeepCopy() LoadOpts {
-	bytes, err := maputil.YamlMarshal(o)
+	bytes, err := yaml.Marshal(o)
 	if err != nil {
 		panic(err)
 	}

pkg/app/two_pass_renderer_test.go

@@ -4,11 +4,10 @@ import (
 	"strings"
 	"testing"
 
-	"gopkg.in/yaml.v3"
-
 	"github.com/helmfile/helmfile/pkg/remote"
 	"github.com/helmfile/helmfile/pkg/state"
 	"github.com/helmfile/helmfile/pkg/testhelper"
+	"github.com/helmfile/helmfile/pkg/yaml"
 )
 
 // nolint: unparam

pkg/environment/environment.go

@@ -2,9 +2,9 @@ package environment
 
 import (
 	"github.com/imdario/mergo"
-	"gopkg.in/yaml.v3"
 
 	"github.com/helmfile/helmfile/pkg/maputil"
+	"github.com/helmfile/helmfile/pkg/yaml"
 )
 
 type Environment struct {
@@ -16,7 +16,7 @@ type Environment struct {
 var EmptyEnvironment Environment
 
 func (e Environment) DeepCopy() Environment {
-	valuesBytes, err := maputil.YamlMarshal(e.Values)
+	valuesBytes, err := yaml.Marshal(e.Values)
 	if err != nil {
 		panic(err)
 	}
@@ -29,7 +29,7 @@ func (e Environment) DeepCopy() Environment {
 		panic(err)
 	}
 
-	defaultsBytes, err := maputil.YamlMarshal(e.Defaults)
+	defaultsBytes, err := yaml.Marshal(e.Defaults)
 	if err != nil {
 		panic(err)
 	}

pkg/helmexec/exec.go

@@ -14,12 +14,12 @@ import (
 	"github.com/Masterminds/semver/v3"
 	"go.uber.org/zap"
 	"go.uber.org/zap/zapcore"
-	"gopkg.in/yaml.v3"
 	"helm.sh/helm/v3/pkg/chart"
 	"helm.sh/helm/v3/pkg/cli"
 	"helm.sh/helm/v3/pkg/plugin"
 
 	"github.com/helmfile/helmfile/pkg/envvar"
+	"github.com/helmfile/helmfile/pkg/yaml"
 )
 
 type decryptedSecret struct {

pkg/maputil/yamlutil.go

@@ -1,18 +0,0 @@
-package maputil
-
-import (
-	"bytes"
-
-	"gopkg.in/yaml.v3"
-)
-
-func YamlMarshal(v interface{}) ([]byte, error) {
-	var b bytes.Buffer
-	yamlEncoder := yaml.NewEncoder(&b)
-	yamlEncoder.SetIndent(2)
-	err := yamlEncoder.Encode(v)
-	defer func() {
-		_ = yamlEncoder.Close()
-	}()
-	return b.Bytes(), err
-}

pkg/remote/remote.go

@@ -14,10 +14,10 @@ import (
 	"github.com/hashicorp/go-getter/helper/url"
 	"go.uber.org/multierr"
 	"go.uber.org/zap"
-	"gopkg.in/yaml.v3"
 
 	"github.com/helmfile/helmfile/pkg/envvar"
 	"github.com/helmfile/helmfile/pkg/filesystem"
+	"github.com/helmfile/helmfile/pkg/yaml"
 )
 
 var disableInsecureFeatures bool

pkg/state/chart_dependency.go

@@ -11,11 +11,10 @@ import (
 	goversion "github.com/hashicorp/go-version"
 	"github.com/r3labs/diff"
 	"go.uber.org/zap"
-	"gopkg.in/yaml.v3"
 
 	"github.com/helmfile/helmfile/pkg/app/version"
 	"github.com/helmfile/helmfile/pkg/helmexec"
-	"github.com/helmfile/helmfile/pkg/maputil"
+	"github.com/helmfile/helmfile/pkg/yaml"
 )
 
 type ChartMeta struct {
@@ -309,7 +308,7 @@ func (m *chartDependencyManager) updateHelm3(shell helmexec.DependencyUpdater, w
 	chartMetaContent := fmt.Sprintf("name: %s\nversion: 1.0.0\napiVersion: v2\n", m.Name)
 
 	// Generate `requirements.yaml` of the temporary local chart from the helmfile state
-	reqsContent, err := maputil.YamlMarshal(unresolved.ToChartRequirements())
+	reqsContent, err := yaml.Marshal(unresolved.ToChartRequirements())
 	if err != nil {
 		return nil, err
 	}
@@ -327,7 +326,7 @@ func (m *chartDependencyManager) updateHelm2(shell helmexec.DependencyUpdater, w
 	}
 
 	// Generate `requirements.yaml` of the temporary local chart from the helmfile state
-	reqsContent, err := maputil.YamlMarshal(unresolved.ToChartRequirements())
+	reqsContent, err := yaml.Marshal(unresolved.ToChartRequirements())
 	if err != nil {
 		return nil, err
 	}
@@ -393,7 +392,7 @@ func (m *chartDependencyManager) doUpdate(chartLockFile string, unresolved *Unre
 
 	lockedReqs.Version = version.Version()
 
-	updatedLockFileContent, err = maputil.YamlMarshal(lockedReqs)
+	updatedLockFileContent, err = yaml.Marshal(lockedReqs)
 
 	if err != nil {
 		return nil, err

pkg/state/create.go

@@ -1,7 +1,6 @@
 package state
 
 import (
-	"bytes"
 	"errors"
 	"fmt"
 	"io"
@@ -9,13 +8,13 @@ import (
 	"github.com/imdario/mergo"
 	"github.com/variantdev/vals"
 	"go.uber.org/zap"
-	"gopkg.in/yaml.v3"
 
 	"github.com/helmfile/helmfile/pkg/environment"
 	"github.com/helmfile/helmfile/pkg/filesystem"
 	"github.com/helmfile/helmfile/pkg/helmexec"
 	"github.com/helmfile/helmfile/pkg/maputil"
 	"github.com/helmfile/helmfile/pkg/remote"
+	"github.com/helmfile/helmfile/pkg/yaml"
 )
 
 const (
@@ -89,9 +88,7 @@ func (c *StateCreator) Parse(content []byte, baseDir, file string) (*HelmState,
 
 	state.LockFile = c.lockFile
 
-	decoder := yaml.NewDecoder(bytes.NewReader(content))
-
-	decoder.KnownFields(c.Strict)
+	decode := yaml.NewDecoder(content, c.Strict)
 
 	i := 0
 	for {
@@ -99,7 +96,7 @@ func (c *StateCreator) Parse(content []byte, baseDir, file string) (*HelmState,
 
 		var intermediate HelmState
 
-		err := decoder.Decode(&intermediate)
+		err := decode(&intermediate)
 		if err == io.EOF {
 			break
 		} else if err != nil {

pkg/state/envvals_loader.go

@@ -6,13 +6,13 @@ import (
 
 	"github.com/imdario/mergo"
 	"go.uber.org/zap"
-	"gopkg.in/yaml.v3"
 
 	"github.com/helmfile/helmfile/pkg/environment"
 	"github.com/helmfile/helmfile/pkg/filesystem"
 	"github.com/helmfile/helmfile/pkg/maputil"
 	"github.com/helmfile/helmfile/pkg/remote"
 	"github.com/helmfile/helmfile/pkg/tmpl"
+	"github.com/helmfile/helmfile/pkg/yaml"
 )
 
 type EnvironmentValuesLoader struct {

pkg/state/release.go

@@ -3,10 +3,8 @@ package state
 import (
 	"fmt"
 
-	"gopkg.in/yaml.v3"
-
-	"github.com/helmfile/helmfile/pkg/maputil"
 	"github.com/helmfile/helmfile/pkg/tmpl"
+	"github.com/helmfile/helmfile/pkg/yaml"
 )
 
 func (r ReleaseSpec) ExecuteTemplateExpressions(renderer *tmpl.FileRenderer) (*ReleaseSpec, error) {
@@ -99,7 +97,7 @@ func (r ReleaseSpec) ExecuteTemplateExpressions(renderer *tmpl.FileRenderer) (*R
 		for i, t := range result.ValuesTemplate {
 			switch ts := t.(type) {
 			case map[interface{}]interface{}, map[string]interface{}:
-				serialized, err := maputil.YamlMarshal(ts)
+				serialized, err := yaml.Marshal(ts)
 				if err != nil {
 					return nil, fmt.Errorf("failed executing template expressions in release \"%s\".values[%d] = \"%v\": %v", r.Name, i, ts, err)
 				}
@@ -202,7 +200,7 @@ func (r ReleaseSpec) ExecuteTemplateExpressions(renderer *tmpl.FileRenderer) (*R
 }
 
 func (r ReleaseSpec) Clone() (*ReleaseSpec, error) {
-	serialized, err := maputil.YamlMarshal(r)
+	serialized, err := yaml.Marshal(r)
 	if err != nil {
 		return nil, fmt.Errorf("failed cloning release \"%s\": %v", r.Name, err)
 	}

pkg/state/state.go

@@ -22,16 +22,15 @@ import (
 	"github.com/variantdev/chartify"
 	"github.com/variantdev/vals"
 	"go.uber.org/zap"
-	"gopkg.in/yaml.v3"
 
 	"github.com/helmfile/helmfile/pkg/environment"
 	"github.com/helmfile/helmfile/pkg/event"
 	"github.com/helmfile/helmfile/pkg/filesystem"
 	"github.com/helmfile/helmfile/pkg/helmexec"
-	"github.com/helmfile/helmfile/pkg/maputil"
 	"github.com/helmfile/helmfile/pkg/policy"
 	"github.com/helmfile/helmfile/pkg/remote"
 	"github.com/helmfile/helmfile/pkg/tmpl"
+	"github.com/helmfile/helmfile/pkg/yaml"
 )
 
 const (
@@ -87,13 +86,9 @@ type ReleaseSetSpec struct {
 // helmStateAlias is helm state alias
 type helmStateAlias HelmState
 
-func (hs HelmState) MarshalYAML() (interface{}, error) {
-	return helmStateAlias(hs), nil
-}
-
-func (hs *HelmState) UnmarshalYAML(value *yaml.Node) error {
+func (hs *HelmState) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	helmStateInfo := make(map[string]interface{})
-	if err := value.DecodeWithOptions(&helmStateInfo, yaml.DecodeOptions{KnownFields: true}); err != nil {
+	if err := unmarshal(&helmStateInfo); err != nil {
 		return err
 	}
 
@@ -105,7 +100,7 @@ func (hs *HelmState) UnmarshalYAML(value *yaml.Node) error {
 		fmt.Fprintf(os.Stderr, "Warning: %v\n", err)
 	}
 
-	return value.DecodeWithOptions((*helmStateAlias)(hs), yaml.DecodeOptions{KnownFields: true})
+	return unmarshal((*helmStateAlias)(hs))
 }
 
 // HelmState structure for the helmfile
@@ -1552,8 +1547,8 @@ func (st *HelmState) WriteReleasesValues(helm helmexec.Interface, additionalValu
 
 		var buf bytes.Buffer
 
-		y := yaml.NewEncoder(&buf)
-		if err := y.Encode(merged); err != nil {
+		encoder := yaml.NewEncoder(&buf)
+		if err := encoder.Encode(merged); err != nil {
 			return []error{err}
 		}
 
@@ -2708,7 +2703,7 @@ func (st *HelmState) RenderReleaseValuesFileToBytes(release *ReleaseSpec, path s
 			return nil, err
 		}
 
-		return maputil.YamlMarshal(parsedYaml)
+		return yaml.Marshal(parsedYaml)
 	}
 
 	return rawBytes, nil
@@ -2896,7 +2891,7 @@ func (st *HelmState) generateSecretValuesFiles(helm helmexec.Interface, release
 				return nil, err
 			}
 		default:
-			bs, err := maputil.YamlMarshal(value)
+			bs, err := yaml.Marshal(value)
 			if err != nil {
 				return nil, err
 			}
@@ -3127,10 +3122,10 @@ func (p SubHelmfileSpec) MarshalYAML() (interface{}, error) {
 }
 
 // UnmarshalYAML will unmarshal the helmfile yaml section and fill the SubHelmfileSpec structure
-// this is required to keep allowing string scalar for defining helmfile
-func (hf *SubHelmfileSpec) UnmarshalYAML(value *yaml.Node) error {
+// this is required go-yto keep allowing string scalar for defining helmfile
+func (hf *SubHelmfileSpec) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	var tmp interface{}
-	if err := value.Decode(&tmp); err != nil {
+	if err := unmarshal(&tmp); err != nil {
 		return err
 	}
 
@@ -3145,7 +3140,7 @@ func (hf *SubHelmfileSpec) UnmarshalYAML(value *yaml.Node) error {
 
 			Environment SubhelmfileEnvironmentSpec `yaml:",inline"`
 		}
-		if err := value.Decode(&subHelmfileSpecTmp); err != nil {
+		if err := unmarshal(&subHelmfileSpecTmp); err != nil {
 			return err
 		}
 		hf.Path = subHelmfileSpecTmp.Path
@@ -3330,7 +3325,7 @@ func (st *HelmState) GenerateOutputFilePath(release *ReleaseSpec, outputFileTemp
 }
 
 func (st *HelmState) ToYaml() (string, error) {
-	if result, err := maputil.YamlMarshal(st); err != nil {
+	if result, err := yaml.Marshal(st); err != nil {
 		return "", err
 	} else {
 		return string(result), nil

pkg/state/state_exec_tmpl.go

@@ -4,9 +4,8 @@ import (
 	"fmt"
 	"reflect"
 
-	"gopkg.in/yaml.v3"
-
 	"github.com/helmfile/helmfile/pkg/tmpl"
+	"github.com/helmfile/helmfile/pkg/yaml"
 )
 
 func (st *HelmState) Values() map[string]interface{} {

pkg/state/state_exec_tmpl_test.go

@@ -67,11 +67,11 @@ func TestHelmState_executeTemplates(t *testing.T) {
 				Name:               "app-dev",
 				Namespace:          "dev",
 				Labels:             map[string]string{"id": "app"},
-				InstalledTemplate:  func(i string) *string { return &i }(`{{ eq .Release.Labels.id "app" | ternary "yes" "no" }}`),
+				InstalledTemplate:  func(i string) *string { return &i }(`{{ eq .Release.Labels.id "app" | ternary "true" "false" }}`),
 				VerifyTemplate:     func(i string) *string { return &i }(`{{ true }}`),
 				Verify:             func(i bool) *bool { return &i }(false),
 				WaitTemplate:       func(i string) *string { return &i }(`{{ false }}`),
-				TillerlessTemplate: func(i string) *string { return &i }(`yes`),
+				TillerlessTemplate: func(i string) *string { return &i }(`true`),
 			},
 			want: ReleaseSpec{
 				Chart:      "test-chart",

pkg/tmpl/context_funcs.go

@@ -14,11 +14,10 @@ import (
 	"text/template"
 
 	"golang.org/x/sync/errgroup"
-	"gopkg.in/yaml.v3"
 
 	"github.com/helmfile/helmfile/pkg/envvar"
 	"github.com/helmfile/helmfile/pkg/helmexec"
-	"github.com/helmfile/helmfile/pkg/maputil"
+	"github.com/helmfile/helmfile/pkg/yaml"
 )
 
 type Values = map[string]interface{}
@@ -279,7 +278,7 @@ func (c *Context) Tpl(text string, data interface{}) (string, error) {
 }
 
 func ToYaml(v interface{}) (string, error) {
-	data, err := maputil.YamlMarshal(v)
+	data, err := yaml.Marshal(v)
 	if err != nil {
 		return "", err
 	}

pkg/yaml/yaml.go

@@ -0,0 +1,84 @@
+package yaml
+
+import (
+	"bytes"
+	"io"
+
+	"github.com/goccy/go-yaml"
+	v2 "gopkg.in/yaml.v2"
+)
+
+var (
+	// We'll derive the default from the build once
+	// is merged
+	GoccyGoYaml bool = true
+)
+
+type Encoder interface {
+	Encode(interface{}) error
+	Close() error
+}
+
+// NewEncoder creates and returns a function that is used to encode a Go object to a YAML document
+func NewEncoder(w io.Writer) Encoder {
+	if GoccyGoYaml {
+		return yaml.NewEncoder(w)
+	}
+
+	return v2.NewEncoder(w)
+}
+
+func Unmarshal(data []byte, v interface{}) error {
+	if GoccyGoYaml {
+		return yaml.Unmarshal(data, v)
+	}
+
+	return v2.Unmarshal(data, v)
+}
+
+// NewDecoder creates and returns a function that is used to decode a YAML document
+// contained within the YAML document stream per each call.
+// When strict is true, this function ensures that every field found in the YAML document
+// to have the corresponding field in the decoded Go struct.
+func NewDecoder(data []byte, strict bool) func(interface{}) error {
+	if GoccyGoYaml {
+		var opts []yaml.DecodeOption
+		if strict {
+			opts = append(opts, yaml.DisallowUnknownField())
+		}
+
+		decoder := yaml.NewDecoder(
+			bytes.NewReader(data),
+			opts...,
+		)
+
+		return func(v interface{}) error {
+			return decoder.Decode(v)
+		}
+	}
+
+	decoder := v2.NewDecoder(bytes.NewReader(data))
+	decoder.SetStrict(strict)
+
+	return func(v interface{}) error {
+		return decoder.Decode(v)
+	}
+}
+
+func Marshal(v interface{}) ([]byte, error) {
+	if GoccyGoYaml {
+		var b bytes.Buffer
+		yamlEncoder := yaml.NewEncoder(
+			&b,
+			yaml.IndentSequence(true),
+			yaml.Indent(2),
+		)
+		err := yamlEncoder.Encode(v)
+		defer func() {
+			_ = yamlEncoder.Close()
+		}()
+		return b.Bytes(), err
+	}
+
+	return v2.Marshal(v)
+}

pkg/yaml/yaml_test.go

@@ -1,4 +1,4 @@
-package maputil
+package yaml
 
 import (
 	"testing"
@@ -27,7 +27,7 @@ func TestYamlMarshal(t *testing.T) {
 	}
 
 	for _, tt := range tests {
-		actual, err := YamlMarshal(tt)
+		actual, err := Marshal(tt)
 		require.NoError(t, err)
 		require.Equal(t, tt.expected, string(actual))
 	}

test/e2e/template/helmfile/snapshot_test.go

@@ -15,11 +15,11 @@ import (
 
 	"github.com/stretchr/testify/require"
 	"github.com/variantdev/chartify/helmtesting"
-	"gopkg.in/yaml.v3"
 
 	"github.com/helmfile/helmfile/pkg/app"
 	"github.com/helmfile/helmfile/pkg/envvar"
 	"github.com/helmfile/helmfile/pkg/helmexec"
+	"github.com/helmfile/helmfile/pkg/yaml"
 )
 
 var (