resource/aws_cloudwatch_event_target: Prevent potential panic and passthrough custom event_bus_name in v0 state upgrade

aws/resource_aws_cloudwatch_event_target_migrate.go

@@ -171,7 +171,13 @@ func resourceAwsCloudWatchEventTargetV0() *schema.Resource {
 }
 
 func resourceAwsCloudWatchEventTargetStateUpgradeV0(_ context.Context, rawState map[string]interface{}, meta interface{}) (map[string]interface{}, error) {
-	rawState["event_bus_name"] = tfevents.DefaultEventBusName
+	if rawState == nil {
+		rawState = map[string]interface{}{}
+	}
+
+	if _, ok := rawState["event_bus_name"]; !ok {
+		rawState["event_bus_name"] = tfevents.DefaultEventBusName
+	}
 
 	return rawState, nil
 }

aws/resource_aws_cloudwatch_event_target_migrate_test.go

@@ -14,6 +14,15 @@ func testResourceAwsCloudWatchEventTargetStateDataV0() map[string]interface{} {
 	}
 }
 
+func testResourceAwsCloudWatchEventTargetStateDataV0EventBusName() map[string]interface{} {
+	return map[string]interface{}{
+		"arn":            "arn:aws:test:us-east-1:123456789012:test", //lintignore:AWSAT003,AWSAT005
+		"event_bus_name": "testbus",
+		"rule":           "testrule",
+		"target_id":      "testtargetid",
+	}
+}
+
 func testResourceAwsCloudWatchEventTargetStateDataV1() map[string]interface{} {
 	v0 := testResourceAwsCloudWatchEventTargetStateDataV0()
 	return map[string]interface{}{
@@ -24,6 +33,16 @@ func testResourceAwsCloudWatchEventTargetStateDataV1() map[string]interface{} {
 	}
 }
 
+func testResourceAwsCloudWatchEventTargetStateDataV1EventBusName() map[string]interface{} {
+	v0 := testResourceAwsCloudWatchEventTargetStateDataV0EventBusName()
+	return map[string]interface{}{
+		"arn":            v0["arn"],
+		"event_bus_name": v0["event_bus_name"],
+		"rule":           v0["rule"],
+		"target_id":      v0["target_id"],
+	}
+}
+
 func TestResourceAwsCloudWatchEventTargetStateUpgradeV0(t *testing.T) {
 	expected := testResourceAwsCloudWatchEventTargetStateDataV1()
 	actual, err := resourceAwsCloudWatchEventTargetStateUpgradeV0(context.Background(), testResourceAwsCloudWatchEventTargetStateDataV0(), nil)
@@ -35,3 +54,15 @@ func TestResourceAwsCloudWatchEventTargetStateUpgradeV0(t *testing.T) {
 		t.Fatalf("\n\nexpected:\n\n%#v\n\ngot:\n\n%#v\n\n", expected, actual)
 	}
 }
+
+func TestResourceAwsCloudWatchEventTargetStateUpgradeV0EventBusName(t *testing.T) {
+	expected := testResourceAwsCloudWatchEventTargetStateDataV1EventBusName()
+	actual, err := resourceAwsCloudWatchEventTargetStateUpgradeV0(context.Background(), testResourceAwsCloudWatchEventTargetStateDataV0EventBusName(), nil)
+	if err != nil {
+		t.Fatalf("error migrating state: %s", err)
+	}
+
+	if !reflect.DeepEqual(expected, actual) {
+		t.Fatalf("\n\nexpected:\n\n%#v\n\ngot:\n\n%#v\n\n", expected, actual)
+	}
+}