Fix panic: missing check if state is a cty null value

pkg/resource/select.go

@@ -38,17 +38,17 @@ func (f Filter) Apply(res []awsls.Resource) []awsls.Resource {
 
 func GetTags(r *awsls.Resource) (map[string]string, error) {
 	if r == nil || r.UpdatableResource == nil {
-		return nil, fmt.Errorf("resource is nil")
+		return nil, fmt.Errorf("resource is nil: %+v", r)
 	}
 
 	state := r.State()
 
-	if state == nil {
-		return nil, fmt.Errorf("state is nil")
+	if state == nil || state.IsNull() {
+		return nil, fmt.Errorf("state is nil: %+v", state)
 	}
 
 	if !state.CanIterateElements() {
-		return nil, fmt.Errorf("cannot iterate: %s", *state)
+		return nil, fmt.Errorf("cannot iterate: %s", state.GoString())
 	}
 
 	attrValue, ok := state.AsValueMap()["tags"]

pkg/resource/select_test.go

@@ -1,12 +1,16 @@
 package resource_test
 
 import (
+	"reflect"
 	"testing"
 	"time"
 
+	"github.com/zclconf/go-cty/cty"
+
 	"github.com/aws/aws-sdk-go/aws"
 	awsls "github.com/jckuester/awsls/aws"
 	"github.com/jckuester/awsweeper/pkg/resource"
+	terradozerRes "github.com/jckuester/terradozer/pkg/resource"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -409,3 +413,110 @@ func TestYamlFilter_Apply_NegatedStringFilter(t *testing.T) {
 	require.Len(t, result, 1)
 	assert.Equal(t, "select-this", result[0].ID)
 }
+
+func TestGetTags(t *testing.T) {
+	tests := []struct {
+		name    string
+		arg     *awsls.Resource
+		want    map[string]string
+		wantErr string
+	}{
+		{
+			name:    "resource is nil",
+			wantErr: "resource is nil: <nil>",
+		},
+		{
+			name:    "embedded updatable resource is nil",
+			arg:     &awsls.Resource{},
+			wantErr: "resource is nil: &{Type: ID: Region: Tags:map[] CreatedAt:<nil> UpdatableResource:<nil>}",
+		},
+		{
+			name: "state is nil",
+			arg: &awsls.Resource{
+				UpdatableResource: &terradozerRes.Resource{},
+			},
+			wantErr: "state is nil: <nil>",
+		},
+		{
+			name: "state is nil value",
+			arg: &awsls.Resource{
+				UpdatableResource: terradozerRes.NewWithState("aws_foo", "1234", nil, &cty.NilVal),
+			},
+			wantErr: "state is nil: &{ty:{typeImpl:<nil>} v:<nil>}",
+		},
+		{
+			name: "null map",
+			arg: &awsls.Resource{
+				UpdatableResource: terradozerRes.NewWithState("aws_foo", "1234",
+					nil, ctyValuePtr(cty.NullVal(cty.Map(cty.String)))),
+			},
+			wantErr: "state is nil: &{ty:{typeImpl:{typeImplSigil:{} ElementTypeT:{typeImpl:{typeImplSigil:{} Kind:83}}}} v:<nil>}",
+		},
+		{
+			name: "unhandled type",
+			arg: &awsls.Resource{
+				UpdatableResource: terradozerRes.NewWithState("aws_foo", "1234",
+					nil, ctyValuePtr(cty.ObjectVal(map[string]cty.Value{
+						"tags": cty.StringVal("foo"),
+					}))),
+			},
+			wantErr: "currently unhandled type: string",
+		},
+		{
+			name: "tags attribute not found",
+			arg: &awsls.Resource{
+				UpdatableResource: terradozerRes.NewWithState("aws_foo", "1234",
+					nil, ctyValuePtr(cty.ObjectVal(map[string]cty.Value{
+						"tag": cty.StringVal("foo"),
+					}))),
+			},
+			wantErr: "attribute not found: tags",
+		},
+		{
+			name: "cannot iterate element",
+			arg: &awsls.Resource{
+				UpdatableResource: terradozerRes.NewWithState("aws_foo", "1234",
+					nil, ctyValuePtr(cty.StringVal("foo"))),
+			},
+			wantErr: "cannot iterate: cty.StringVal(\"foo\")",
+		},
+		{
+			name: "empty map of tags",
+			arg: &awsls.Resource{
+				UpdatableResource: terradozerRes.NewWithState("aws_foo", "1234",
+					nil, ctyValuePtr(cty.ObjectVal(map[string]cty.Value{
+						"tags": cty.MapValEmpty(cty.String),
+					}))),
+			},
+			want: map[string]string{},
+		},
+		{
+			name: "some tags",
+			arg: &awsls.Resource{
+				UpdatableResource: terradozerRes.NewWithState("aws_foo", "1234",
+					nil, ctyValuePtr(cty.ObjectVal(map[string]cty.Value{
+						"tags": cty.MapVal(map[string]cty.Value{"foo": cty.StringVal("bar")}),
+					}))),
+			},
+			want: map[string]string{"foo": "bar"},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := resource.GetTags(tt.arg)
+
+			if tt.wantErr != "" {
+				assert.EqualError(t, err, tt.wantErr)
+			} else {
+				require.NoError(t, err)
+				if !reflect.DeepEqual(got, tt.want) {
+					t.Errorf("GetTags() got = %v, want %v", got, tt.want)
+				}
+			}
+		})
+	}
+}
+
+func ctyValuePtr(v cty.Value) *cty.Value {
+	return &v
+}