fix: properly handle YAML comment stripping for multi-doc

Fixes #7425

The previously used method doesn't handle YAML multi-doc, incorrectly
stripping only the first document and throwing away everything else.

Signed-off-by: Andrey Smirnov <andrey.smirnov@talos-systems.com>

cmd/talosctl/cmd/talos/edit.go

@@ -19,11 +19,11 @@ import (
 	"github.com/spf13/cobra"
 	"google.golang.org/protobuf/types/known/durationpb"
 	"gopkg.in/yaml.v3"
-	cmdutil "k8s.io/kubectl/pkg/cmd/util"
 	"k8s.io/kubectl/pkg/cmd/util/editor"
 	"k8s.io/kubectl/pkg/cmd/util/editor/crlf"
 
 	"github.com/siderolabs/talos/cmd/talosctl/pkg/talos/helpers"
+	"github.com/siderolabs/talos/cmd/talosctl/pkg/talos/yamlstrip"
 	"github.com/siderolabs/talos/pkg/machinery/api/machine"
 	"github.com/siderolabs/talos/pkg/machinery/client"
 	"github.com/siderolabs/talos/pkg/machinery/constants"
@@ -111,7 +111,7 @@ func editFn(c *client.Client) func(context.Context, string, resource.Resource, e
 			edited = stripEditingComment(edited)
 
 			// If we're retrying the loop because of an error, and no change was made in the file, short-circuit
-			if lastError != "" && bytes.Equal(cmdutil.StripComments(editedDiff), cmdutil.StripComments(edited)) {
+			if lastError != "" && bytes.Equal(yamlstrip.Comments(editedDiff), yamlstrip.Comments(edited)) {
 				if _, err = os.Stat(path); !os.IsNotExist(err) {
 					message := addEditingComment(lastError)
 					message += fmt.Sprintf("A copy of your changes has been stored to %q\nEdit canceled, no valid changes were saved.\n", path)
@@ -120,7 +120,7 @@ func editFn(c *client.Client) func(context.Context, string, resource.Resource, e
 				}
 			}
 
-			if len(bytes.TrimSpace(bytes.TrimSpace(cmdutil.StripComments(edited)))) == 0 {
+			if len(bytes.TrimSpace(bytes.TrimSpace(yamlstrip.Comments(edited)))) == 0 {
 				fmt.Fprintln(os.Stderr, "Apply was skipped: empty file.")
 
 				break

cmd/talosctl/cmd/talos/patch.go

@@ -15,9 +15,9 @@ import (
 	"github.com/spf13/cobra"
 	"google.golang.org/protobuf/types/known/durationpb"
 	"gopkg.in/yaml.v3"
-	cmdutil "k8s.io/kubectl/pkg/cmd/util"
 
 	"github.com/siderolabs/talos/cmd/talosctl/pkg/talos/helpers"
+	"github.com/siderolabs/talos/cmd/talosctl/pkg/talos/yamlstrip"
 	"github.com/siderolabs/talos/pkg/machinery/api/machine"
 	"github.com/siderolabs/talos/pkg/machinery/client"
 	"github.com/siderolabs/talos/pkg/machinery/config/configpatcher"
@@ -67,8 +67,8 @@ func patchFn(c *client.Client, patches []configpatcher.Patch) func(context.Conte
 		})
 
 		if bytes.Equal(
-			bytes.TrimSpace(cmdutil.StripComments(patched)),
-			bytes.TrimSpace(cmdutil.StripComments(body)),
+			bytes.TrimSpace(yamlstrip.Comments(patched)),
+			bytes.TrimSpace(yamlstrip.Comments(body)),
 		) {
 			fmt.Fprintln(os.Stderr, "Apply was skipped: no changes detected.")
 

cmd/talosctl/pkg/talos/yamlstrip/testdata/malformed.in.yaml

@@ -0,0 +1,4 @@
+data:
+  # This is a comment
+  some:
+    other: a: b: c

cmd/talosctl/pkg/talos/yamlstrip/testdata/malformed.out.yaml

@@ -0,0 +1,3 @@
+data:
+  some:
+    other: a: b: c

cmd/talosctl/pkg/talos/yamlstrip/testdata/multidoc.in.yaml

@@ -0,0 +1,18 @@
+# siderolink config
+apiVersion: v1alpha1
+kind: SideroLinkConfig # kind of the document
+# apiUrl is the URL of the SideroLink API endpoint
+apiUrl: grpc://172.20.0.1:4000/?jointoken=foo
+---
+apiVersion: v1alpha1
+kind: KmsgLogConfig
+name: apiSink # named document
+url: tcp://[fdae:41e4:649b:9303::1]:4001/
+options: # options are optional
+  # more options
+  foo: bar # this option
+---
+apiVersion: v1alpha1
+kind: EventSinkConfig
+endpoint: "[fdae:41e4:649b:9303::1]:8080"
+# end of document

cmd/talosctl/pkg/talos/yamlstrip/testdata/multidoc.out.yaml

@@ -0,0 +1,14 @@
+apiVersion: v1alpha1
+kind: SideroLinkConfig
+apiUrl: grpc://172.20.0.1:4000/?jointoken=foo
+---
+apiVersion: v1alpha1
+kind: KmsgLogConfig
+name: apiSink
+url: tcp://[fdae:41e4:649b:9303::1]:4001/
+options:
+    foo: bar
+---
+apiVersion: v1alpha1
+kind: EventSinkConfig
+endpoint: "[fdae:41e4:649b:9303::1]:8080"

cmd/talosctl/pkg/talos/yamlstrip/yamlstrip.go

@@ -0,0 +1,87 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+// Package yamlstrip provides YAML file manipulation.
+package yamlstrip
+
+import (
+	"bytes"
+	"errors"
+	"io"
+
+	"gopkg.in/yaml.v3"
+)
+
+// Comments strips comments from a YAML file.
+//
+// If the YAML file is parseable, it will be accurately stripped. Otherwise, it
+// will be stripped in a best-effort manner.
+func Comments(b []byte) []byte {
+	stripped, err := stripViaDecoding(b)
+	if err != nil {
+		stripped = stripManual(b)
+	}
+
+	return stripped
+}
+
+func stripViaDecoding(b []byte) ([]byte, error) {
+	var out bytes.Buffer
+
+	decoder := yaml.NewDecoder(bytes.NewReader(b))
+	encoder := yaml.NewEncoder(&out)
+
+	for {
+		var node yaml.Node
+
+		err := decoder.Decode(&node)
+		if err != nil {
+			if errors.Is(err, io.EOF) {
+				break
+			}
+
+			return nil, err
+		}
+
+		removeComments(&node)
+
+		if err = encoder.Encode(&node); err != nil {
+			return nil, err
+		}
+	}
+
+	return out.Bytes(), nil
+}
+
+func removeComments(node *yaml.Node) {
+	node.FootComment = ""
+	node.HeadComment = ""
+	node.LineComment = ""
+
+	for _, child := range node.Content {
+		removeComments(child)
+	}
+}
+
+func stripManual(b []byte) []byte {
+	stripped := []byte{}
+	lines := bytes.Split(b, []byte("\n"))
+
+	for i, line := range lines {
+		trimline := bytes.TrimSpace(line)
+
+		// this is not accurate, but best effort
+		if bytes.HasPrefix(trimline, []byte("#")) && !bytes.HasPrefix(trimline, []byte("#!")) {
+			continue
+		}
+
+		stripped = append(stripped, line...)
+
+		if i < len(lines)-1 {
+			stripped = append(stripped, '\n')
+		}
+	}
+
+	return stripped
+}

cmd/talosctl/pkg/talos/yamlstrip/yamlstrip_test.go

@@ -0,0 +1,36 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package yamlstrip_test
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/siderolabs/talos/cmd/talosctl/pkg/talos/yamlstrip"
+)
+
+func TestComments(t *testing.T) {
+	testCases, err := filepath.Glob(filepath.Join("testdata", "*.in.yaml"))
+	require.NoError(t, err)
+
+	for _, path := range testCases {
+		path := path
+
+		t.Run(filepath.Base(path), func(t *testing.T) {
+			in, err := os.ReadFile(path)
+			require.NoError(t, err)
+
+			expected, err := os.ReadFile(strings.ReplaceAll(path, ".in.yaml", ".out.yaml"))
+			require.NoError(t, err)
+
+			out := yamlstrip.Comments(in)
+			require.Equal(t, string(expected), string(out))
+		})
+	}
+}