resource/aws_elastictranscoder_present: Prevent empty configuration b…

…lock panics (#14092)

Reference: #14087

Previously:

```
=== CONT  TestAccAWSElasticTranscoderPreset_AudioCodecOptions_empty
panic: interface conversion: interface {} is nil, not map[string]interface {}

goroutine 378 [running]:
github.com/terraform-providers/terraform-provider-aws/aws.expandETAudioCodecOptions(0xc000fb9880, 0xc0028af590)
  /Users/bflad/src/github.com/terraform-providers/terraform-provider-aws/aws/resource_aws_elastic_transcoder_preset.go:434 +0x458
github.com/terraform-providers/terraform-provider-aws/aws.expandETAudioParams(0xc000fb9880, 0xc0027d5708)
  /Users/bflad/src/github.com/terraform-providers/terraform-provider-aws/aws/resource_aws_elastic_transcoder_preset.go:423 +0x2a0
github.com/terraform-providers/terraform-provider-aws/aws.resourceAwsElasticTranscoderPresetCreate(0xc000fb9880, 0x66543e0, 0xc002660000, 0x2, 0xbbdb620)
  /Users/bflad/src/github.com/terraform-providers/terraform-provider-aws/aws/resource_aws_elastic_transcoder_preset.go:326 +0x6c
```

Output from acceptance testing:

```
--- PASS: TestAccAWSElasticTranscoderPreset_disappears (13.09s)
--- PASS: TestAccAWSElasticTranscoderPreset_AudioCodecOptions_empty (18.51s)
--- PASS: TestAccAWSElasticTranscoderPreset_Description (18.51s)
--- PASS: TestAccAWSElasticTranscoderPreset_basic (18.98s)
--- PASS: TestAccAWSElasticTranscoderPreset_Full (34.69s)
```

aws/resource_aws_elastic_transcoder_preset.go

@@ -361,7 +361,7 @@ func expandETThumbnails(d *schema.ResourceData) *elastictranscoder.Thumbnails {
  }
 
  l := list.([]interface{})
- if len(l) == 0 {
+ if len(l) == 0 || l[0] == nil {
  return nil
  }
  t := l[0].(map[string]interface{})
@@ -410,7 +410,7 @@ func expandETAudioParams(d *schema.ResourceData) *elastictranscoder.AudioParamet
  }
 
  l := list.([]interface{})
- if len(l) == 0 {
+ if len(l) == 0 || l[0] == nil {
  return nil
  }
  audio := l[0].(map[string]interface{})
@@ -427,7 +427,7 @@ func expandETAudioParams(d *schema.ResourceData) *elastictranscoder.AudioParamet
 
 func expandETAudioCodecOptions(d *schema.ResourceData) *elastictranscoder.AudioCodecOptions {
  l := d.Get("audio_codec_options").([]interface{})
- if len(l) == 0 {
+ if len(l) == 0 || l[0] == nil {
  return nil
  }
 
@@ -456,7 +456,7 @@ func expandETAudioCodecOptions(d *schema.ResourceData) *elastictranscoder.AudioC
 
 func expandETVideoParams(d *schema.ResourceData) *elastictranscoder.VideoParameters {
  l := d.Get("video").([]interface{})
- if len(l) == 0 {
+ if len(l) == 0 || l[0] == nil {
  return nil
  }
  p := l[0].(map[string]interface{})
@@ -541,6 +541,10 @@ func expandETVideoWatermarks(d *schema.ResourceData) []*elastictranscoder.Preset
  var watermarks []*elastictranscoder.PresetWatermark
 
  for _, w := range s.List() {
+ if w == nil {
+ continue
+ }
+
  p := w.(map[string]interface{})
  watermark := &elastictranscoder.PresetWatermark{
  HorizontalAlign: aws.String(p["horizontal_align"].(string)),

aws/resource_aws_elastic_transcoder_preset_test.go

@@ -58,6 +58,33 @@ func TestAccAWSElasticTranscoderPreset_disappears(t *testing.T) {
  })
 }
 
+// Reference: https:/terraform-providers/terraform-provider-aws/issues/14087
+func TestAccAWSElasticTranscoderPreset_AudioCodecOptions_empty(t *testing.T) {
+ var preset elastictranscoder.Preset
+ resourceName := "aws_elastictranscoder_preset.test"
+ rName := acctest.RandomWithPrefix("tf-acc-test")
+
+ resource.ParallelTest(t, resource.TestCase{
+ PreCheck: func() { testAccPreCheck(t); testAccPreCheckAWSElasticTranscoder(t) },
+ Providers: testAccProviders,
+ CheckDestroy: testAccCheckElasticTranscoderPresetDestroy,
+ Steps: []resource.TestStep{
+ {
+ Config: testAccAwsElasticTranscoderPresetConfigAudioCodecOptionsEmpty(rName),
+ Check: resource.ComposeTestCheckFunc(
+ testAccCheckElasticTranscoderPresetExists(resourceName, &preset),
+ ),
+ },
+ {
+ ResourceName: resourceName,
+ ImportState: true,
+ ImportStateVerify: true,
+ ImportStateVerifyIgnore: []string{"audio_codec_options.#"}, // Due to incorrect schema (should be nested under audio)
+ },
+ },
+ })
+}
+
 func TestAccAWSElasticTranscoderPreset_Description(t *testing.T) {
  var preset elastictranscoder.Preset
  resourceName := "aws_elastictranscoder_preset.test"
@@ -240,6 +267,25 @@ resource "aws_elastictranscoder_preset" "test" {
 `, rName)
 }
 
+func testAccAwsElasticTranscoderPresetConfigAudioCodecOptionsEmpty(rName string) string {
+ return fmt.Sprintf(`
+resource "aws_elastictranscoder_preset" "test" {
+ container = "mp4"
+ name = %[1]q
+
+ audio {
+ audio_packing_mode = "SingleTrack"
+ bit_rate = 320
+ channels = 2
+ codec = "mp3"
+ sample_rate = 44100
+ }
+
+ audio_codec_options {}
+}
+`, rName)
+}
+
 func testAccAwsElasticTranscoderPresetConfigDescription(rName string, description string) string {
  return fmt.Sprintf(`
 resource "aws_elastictranscoder_preset" "test" {