fix: skip empty k8s resources

pkg/gator/read_constraints.go

@@ -193,8 +193,10 @@ func ReadK8sResources(r io.Reader) ([]*unstructured.Unstructured, error) {
 		if err != nil {
 			return nil, fmt.Errorf("reading yaml source: %w", err)
 		}
-
-		objs = append(objs, u)
+		// skip empty resources
+		if len(u.Object) > 0 {
+			objs = append(objs, u)
+		}
 	}
 
 	return objs, nil

pkg/gator/read_constraints_test.go

@@ -0,0 +1,77 @@
+package gator
+
+import (
+	"io"
+	"reflect"
+	"strings"
+	"testing"
+
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+)
+
+func TestReadK8sResources(t *testing.T) {
+	type args struct {
+		r io.Reader
+	}
+	tests := []struct {
+		name    string
+		args    args
+		want    []*unstructured.Unstructured
+		wantErr bool
+	}{
+		{
+			name: "test with valid input objects",
+			args: args{r: strings.NewReader("---\n# Source: some/templates/file.yaml\nname: object1\nattrs:\n  - attr1\n  - attr2\n---\n# Source: some/templates/file.yaml\nname: object2\nlabels:\n  - label1\n  - label2\n")},
+			want: []*unstructured.Unstructured{
+				{Object: map[string]interface{}{
+					"name": "object1",
+					"attrs": []interface{}{
+						"attr1",
+						"attr2",
+					},
+				}},
+				{Object: map[string]interface{}{
+					"name": "object2",
+					"labels": []interface{}{
+						"label1",
+						"label2",
+					},
+				}},
+			},
+			wantErr: false,
+		},
+		{
+			name: "test with valid and also empty input objects",
+			args: args{r: strings.NewReader("---\n# Source: some/templates/file.yaml\nname: object1\nattrs:\n  - attr1\n  - attr2\n---\n# Source: some/templates/file.yaml\n# only containing some comment\n---\n# Source: some/templates/file.yaml\nname: object2\nlabels:\n  - label1\n  - label2\n")},
+			want: []*unstructured.Unstructured{
+				{Object: map[string]interface{}{
+					"name": "object1",
+					"attrs": []interface{}{
+						"attr1",
+						"attr2",
+					},
+				}},
+				{Object: map[string]interface{}{
+					"name": "object2",
+					"labels": []interface{}{
+						"label1",
+						"label2",
+					},
+				}},
+			},
+			wantErr: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := ReadK8sResources(tt.args.r)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("ReadK8sResources() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("ReadK8sResources() got = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}