fix: trim leading spaces\newlines in inline manifest contents

In route `LoadPatches` -> `configpatcher.Apply` -> `configloader.NewFromBytes` any leading newlines will be transformed  into `|4` yaml. We want to prevent that.

Closes #7993

Signed-off-by: Dmitriy Matrenichev <dmitry.matrenichev@siderolabs.com>

pkg/machinery/config/configpatcher/apply_test.go

@@ -2,7 +2,6 @@
 // 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/.
 
-//nolint:dupl
 package configpatcher_test
 
 import (
@@ -20,13 +19,16 @@ import (
 var config []byte
 
 //go:embed testdata/apply/expected.yaml
-var expected []byte
+var expected string
 
 //go:embed testdata/multidoc/config.yaml
 var configMultidoc []byte
 
 //go:embed testdata/multidoc/expected.yaml
-var expectedMultidoc []byte
+var expectedMultidoc string
+
+//go:embed testdata/apply/expected_manifests.yaml
+var expectedManifests string
 
 func TestApply(t *testing.T) {
 	patches, err := configpatcher.LoadPatches([]string{
@@ -61,7 +63,7 @@ func TestApply(t *testing.T) {
 			bytes, err := out.Bytes()
 			require.NoError(t, err)
 
-			assert.Equal(t, string(expected), string(bytes))
+			assert.Equal(t, expected, string(bytes))
 		})
 	}
 }
@@ -126,7 +128,7 @@ func TestApplyMultiDoc(t *testing.T) {
 			bytes, err := out.Bytes()
 			require.NoError(t, err)
 
-			assert.Equal(t, string(expectedMultidoc), string(bytes))
+			assert.Equal(t, expectedMultidoc, string(bytes))
 		})
 	}
 }
@@ -170,3 +172,41 @@ func TestApplyAuditPolicy(t *testing.T) {
 		})
 	}
 }
+
+func TestApplyWithManifestNewline(t *testing.T) {
+	patches, err := configpatcher.LoadPatches([]string{
+		"@testdata/apply/strategic4.yaml",
+	})
+	require.NoError(t, err)
+
+	cfg, err := configloader.NewFromBytes(config)
+	require.NoError(t, err)
+
+	for _, tt := range []struct {
+		name  string
+		input configpatcher.Input
+	}{
+		{
+			name:  "WithConfig",
+			input: configpatcher.WithConfig(cfg),
+		},
+		{
+			name:  "WithBytes",
+			input: configpatcher.WithBytes(config),
+		},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			out, err := configpatcher.Apply(tt.input, patches)
+			require.NoError(t, err)
+
+			bytes, err := out.Bytes()
+			require.NoError(t, err)
+
+			// Verify that after all our transformations the YAML is still valid and newline is removed
+			_, err = configloader.NewFromBytes(bytes)
+			require.NoError(t, err)
+
+			assert.Equal(t, expectedManifests, string(bytes))
+		})
+	}
+}

pkg/machinery/config/configpatcher/testdata/apply/expected_manifests.yaml

@@ -0,0 +1,27 @@
+version: v1alpha1
+machine:
+    type: ""
+    token: ""
+    certSANs: []
+    network:
+        hostname: hostname1
+        interfaces:
+            - interface: eth0
+              dhcp: true
+cluster:
+    controlPlane: null
+    inlineManifests:
+        - name: cilium
+          contents: |
+            ---
+            apiVersion: v1
+            kind: ServiceAccount
+            metadata:
+              name: cilium
+              namespace: kube-system
+            ---
+            apiVersion: v1
+            kind: ServiceAccount
+            metadata:
+              name: cilium-operator
+              namespace: kube-system

pkg/machinery/config/configpatcher/testdata/apply/strategic4.yaml

@@ -0,0 +1,17 @@
+cluster:
+  inlineManifests:
+    - name: cilium
+      contents: | # the empty newline below is important
+
+        ---
+        apiVersion: v1
+        kind: ServiceAccount
+        metadata:
+          name: cilium
+          namespace: kube-system
+        ---
+        apiVersion: v1
+        kind: ServiceAccount
+        metadata:
+          name: cilium-operator
+          namespace: kube-system

pkg/machinery/config/types/v1alpha1/v1alpha1_types.go

@@ -2183,6 +2183,23 @@ type VolumeMountConfig struct {
 // ClusterInlineManifests is a list of ClusterInlineManifest.
 type ClusterInlineManifests []ClusterInlineManifest
 
+// UnmarshalYAML implements yaml.Unmarshaler.
+func (manifests *ClusterInlineManifests) UnmarshalYAML(value *yaml.Node) error {
+	var result []ClusterInlineManifest
+
+	if err := value.Decode(&result); err != nil {
+		return err
+	}
+
+	for i := range result {
+		result[i].InlineManifestContents = strings.TrimLeft(result[i].InlineManifestContents, "\t\n\v\f\r")
+	}
+
+	*manifests = result
+
+	return nil
+}
+
 // ClusterInlineManifest struct describes inline bootstrap manifests for the user.
 type ClusterInlineManifest struct {
 	//   description: |