Merge pull request #38804 from hashicorp/b-aws_ecs_task_definition-co…

…ntainer_definitions-first-char

r/aws_ecs_task_definition: Restore `container_definitions` serialization fidelity

.changelog/38804.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+resource/aws_ecs_task_definition: Prevent lowercasing of the first character of JSON keys in `container_definitions.dockerLabels`
+```

internal/service/ecs/task_definition_equivalency.go → internal/service/ecs/container_definitions.go

@@ -4,11 +4,16 @@
 package ecs
 
 import (
+	"fmt"
 	"sort"
+	_ "unsafe" // Required for go:linkname
 
 	"github.com/aws/aws-sdk-go-v2/aws"
+	_ "github.com/aws/aws-sdk-go-v2/service/ecs" // Required for go:linkname
 	awstypes "github.com/aws/aws-sdk-go-v2/service/ecs/types"
+	smithyjson "github.com/aws/smithy-go/encoding/json"
 	tfjson "github.com/hashicorp/terraform-provider-aws/internal/json"
+	itypes "github.com/hashicorp/terraform-provider-aws/internal/types"
 )
 
 func containerDefinitionsAreEquivalent(def1, def2 string, isAWSVPC bool) (bool, error) {
@@ -143,3 +148,36 @@ func (cd containerDefinitions) orderContainers() {
 		return aws.ToString(cd[i].Name) < aws.ToString(cd[j].Name)
 	})
 }
+
+// Dirty hack to avoid any backwards compatibility issues with the AWS SDK for Go v2 migration.
+// Reach down into the SDK and use the same serialization function that the SDK uses.
+//
+//go:linkname serializeContainerDefinitions github.com/aws/aws-sdk-go-v2/service/ecs.awsAwsjson11_serializeDocumentContainerDefinitions
+func serializeContainerDefinitions(v []awstypes.ContainerDefinition, value smithyjson.Value) error
+
+func flattenContainerDefinitions(apiObjects []awstypes.ContainerDefinition) (string, error) {
+	jsonEncoder := smithyjson.NewEncoder()
+	err := serializeContainerDefinitions(apiObjects, jsonEncoder.Value)
+
+	if err != nil {
+		return "", err
+	}
+
+	return jsonEncoder.String(), nil
+}
+
+func expandContainerDefinitions(tfString string) ([]awstypes.ContainerDefinition, error) {
+	var apiObjects []awstypes.ContainerDefinition
+
+	if err := tfjson.DecodeFromString(tfString, &apiObjects); err != nil {
+		return nil, err
+	}
+
+	for i, apiObject := range apiObjects {
+		if itypes.IsZero(&apiObject) {
+			return nil, fmt.Errorf("invalid container definition supplied at index (%d)", i)
+		}
+	}
+
+	return apiObjects, nil
+}

internal/service/ecs/task_definition.go

@@ -26,10 +26,8 @@ import (
 	"github.com/hashicorp/terraform-provider-aws/internal/errs"
 	"github.com/hashicorp/terraform-provider-aws/internal/errs/sdkdiag"
 	"github.com/hashicorp/terraform-provider-aws/internal/flex"
-	tfjson "github.com/hashicorp/terraform-provider-aws/internal/json"
 	tftags "github.com/hashicorp/terraform-provider-aws/internal/tags"
 	"github.com/hashicorp/terraform-provider-aws/internal/tfresource"
-	itypes "github.com/hashicorp/terraform-provider-aws/internal/types"
 	"github.com/hashicorp/terraform-provider-aws/internal/verify"
 	"github.com/hashicorp/terraform-provider-aws/names"
 )
@@ -1211,35 +1209,6 @@ func flattenFSxWinVolumeAuthorizationConfig(config *awstypes.FSxWindowsFileServe
 	return items
 }
 
-func flattenContainerDefinitions(apiObjects []awstypes.ContainerDefinition) (string, error) {
-	json, err := tfjson.EncodeToBytes(apiObjects)
-	if err != nil {
-		return "", err
-	}
-
-	// Remove empty fields and convert first character of keys to lowercase.
-	json = tfjson.RemoveEmptyFields(json)
-	json = tfjson.KeyFirstLower(json)
-
-	return string(json), nil
-}
-
-func expandContainerDefinitions(tfString string) ([]awstypes.ContainerDefinition, error) {
-	var apiObjects []awstypes.ContainerDefinition
-
-	if err := tfjson.DecodeFromString(tfString, &apiObjects); err != nil {
-		return nil, err
-	}
-
-	for i, apiObject := range apiObjects {
-		if itypes.IsZero(&apiObject) {
-			return nil, fmt.Errorf("invalid container definition supplied at index (%d)", i)
-		}
-	}
-
-	return apiObjects, nil
-}
-
 func expandTaskDefinitionEphemeralStorage(config []interface{}) *awstypes.EphemeralStorage {
 	configMap := config[0].(map[string]interface{})