Use UnmarshalStrict for all YAML parsing

Centralize yaml unmarshalling to k8s.io/enhancements/yaml and add an
UnmarshalStrict() function implemented using gopkg.in/yaml.v3

Somehow all of gopkg.in/yaml.v2, gopkg.in/yaml.v3 and sigs.k8s.io/yaml
were being used across the code. Hopefully this unifies and lets us
choose just one.

Update KEPs to fix unmarshalling failures. The one controversial change
would be to support the KEP that added "deprecated" and "removed"
milestones. I opted to add those to the API, but am open to suggestion
on how that planned lifecycle should be encoded in the KEP instead.

Author: spiffxp

api/approval.go

@@ -23,7 +23,8 @@ import (
 
 	"github.com/go-playground/validator/v10"
 	"github.com/pkg/errors"
-	"gopkg.in/yaml.v3"
+
+	"k8s.io/enhancements/pkg/yaml"
 )
 
 type PRRApprovals []*PRRApproval
@@ -108,7 +109,7 @@ func (p *PRRHandler) Parse(in io.Reader) (*PRRApproval, error) {
 		return approval, errors.Wrap(err, "reading file")
 	}
 
-	if err := yaml.Unmarshal(body.Bytes(), &approval); err != nil {
+	if err := yaml.UnmarshalStrict(body.Bytes(), &approval); err != nil {
 		p.Errors = append(p.Errors, errors.Wrap(err, "error unmarshalling YAML"))
 		return approval, errors.Wrap(err, "unmarshalling YAML")
 	}

api/groups.go

@@ -26,7 +26,7 @@ import (
 
 	"github.com/pkg/errors"
 
-	"sigs.k8s.io/yaml"
+	"k8s.io/enhancements/pkg/yaml"
 )
 
 // GroupFetcher is responsible for getting informationg about groups in the
@@ -147,9 +147,10 @@ func (f *RemoteGroupFetcher) FetchPRRApprovers() ([]string, error) {
 	}
 
 	config := &struct {
-		Data map[string][]string `json:"aliases,omitempty"`
+		Data map[string][]string `json:"aliases,omitempty" yaml:"aliases,omitempty"`
 	}{}
-	if err := yaml.Unmarshal(body, config); err != nil {
+
+	if err := yaml.UnmarshalStrict(body, config); err != nil {
 		return nil, errors.Wrap(err, "unmarshalling owners aliases")
 	}
 

api/proposal.go

@@ -26,7 +26,8 @@ import (
 
 	"github.com/go-playground/validator/v10"
 	"github.com/pkg/errors"
-	"gopkg.in/yaml.v3"
+
+	"k8s.io/enhancements/pkg/yaml"
 )
 
 var ValidStages = []string{
@@ -119,7 +120,7 @@ func (k *KEPHandler) Parse(in io.Reader) (*Proposal, error) {
 		kep.Contents = ""
 	}
 
-	if err := yaml.Unmarshal(metadata, &kep); err != nil {
+	if err := yaml.UnmarshalStrict(metadata, &kep); err != nil {
 		k.Errors = append(k.Errors, errors.Wrap(err, "error unmarshalling YAML"))
 		return kep, errors.Wrap(err, "unmarshalling YAML")
 	}
@@ -194,9 +195,11 @@ func (k *KEPHandler) Validate(p *Proposal) []error {
 }
 
 type Milestone struct {
-	Alpha  string `json:"alpha" yaml:"alpha"`
-	Beta   string `json:"beta" yaml:"beta"`
-	Stable string `json:"stable" yaml:"stable"`
+	Alpha      string `json:"alpha" yaml:"alpha"`
+	Beta       string `json:"beta" yaml:"beta"`
+	Stable     string `json:"stable" yaml:"stable"`
+	Deprecated string `json:"deprecated" yaml:"deprecated,omitempty"`
+	Removed    string `json:"removed" yaml:"removed,omitempty"`
 }
 
 type FeatureGate struct {

keps/sig-network/2595-expanded-dns-config/kep.yaml

@@ -31,7 +31,7 @@ latest-milestone: "v1.22"
 milestone:
   alpha: "v1.22"
   beta: "x.y"
-  GA: "x.y"
+  stable: "x.y"
 
 # The following PRR answers are required at alpha release
 # List the feature gate name and the components for which it must be enabled

keps/sig-node/2727-grpc-probe/kep.yaml

@@ -9,7 +9,7 @@ participating-sigs:
   - sig-network
 status: implementable
 creation-date: 2020-04-04
-modified-date: 2021-05-12
+last-updated: 2021-05-12
 reviewers:
   - "@thockin"
   - "@mrunalp"

pkg/repo/repo.go

@@ -30,12 +30,13 @@ import (
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 	"golang.org/x/oauth2"
-	"gopkg.in/yaml.v3"
 
-	"k8s.io/enhancements/api"
-	"k8s.io/enhancements/pkg/kepval"
 	krgh "k8s.io/release/pkg/github"
 	"k8s.io/test-infra/prow/git"
+
+	"k8s.io/enhancements/api"
+	"k8s.io/enhancements/pkg/kepval"
+	"k8s.io/enhancements/pkg/yaml"
 )
 
 const (
@@ -439,7 +440,7 @@ func (r *Repo) loadKEPFromYaml(kepPath string) (*api.Proposal, error) {
 	}
 
 	var p api.Proposal
-	err = yaml.Unmarshal(b, &p)
+	err = yaml.UnmarshalStrict(b, &p)
 	if err != nil {
 		return nil, fmt.Errorf("unable to load KEP metadata: %s", err)
 	}

pkg/repo/repo_test.go

@@ -24,11 +24,11 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/require"
-	"gopkg.in/yaml.v3"
+	"k8s.io/release/pkg/log"
 
 	"k8s.io/enhancements/api"
 	"k8s.io/enhancements/pkg/repo"
-	"k8s.io/release/pkg/log"
+	"k8s.io/enhancements/pkg/yaml"
 )
 
 var fixture = struct {
@@ -91,7 +91,7 @@ func TestProposalValidate(t *testing.T) {
 			require.NoError(t, err)
 
 			var p api.Proposal
-			err = yaml.Unmarshal(b, &p)
+			err = yaml.UnmarshalStrict(b, &p)
 			require.NoError(t, err)
 
 			errs := parser.Validate(&p)

pkg/repo/write_test.go

@@ -27,7 +27,8 @@ import (
 
 	"k8s.io/enhancements/api"
 	"k8s.io/enhancements/pkg/repo"
-	"sigs.k8s.io/yaml"
+
+	"k8s.io/enhancements/pkg/yaml"
 )
 
 // TODO: Consider using afero to mock the filesystem here
@@ -126,7 +127,7 @@ func TestWriteKep(t *testing.T) {
 			require.NoError(t, err)
 
 			var p api.Proposal
-			err = yaml.Unmarshal(b, &p)
+			err = yaml.UnmarshalStrict(b, &p)
 			require.NoError(t, err)
 
 			p.OwningSIG = tc.sig

pkg/yaml/yaml.go

@@ -0,0 +1,39 @@
+/*
+Copyright 2021 The Kubernetes 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 yaml
+
+import (
+	"bytes"
+
+	"gopkg.in/yaml.v3"
+)
+
+// UnmarshalStrict unmarshals the contents of body into the given interface,
+// and returns an error if any duplicate or unknown fields are encountered
+func UnmarshalStrict(body []byte, v interface{}) error {
+	r := bytes.NewReader(body)
+	d := yaml.NewDecoder(r)
+	d.KnownFields(true)
+	err := d.Decode(v)
+	return err
+}
+
+// Marshal returns a byte array containing a YAML representation of the
+// given interface, and a non-nil error if there was an error
+func Marhsal(v interface{}) ([]byte, error) {
+	return yaml.Marshal(v)
+}