Data types are null when being created, defend legacy value converter…

… from nulls

CHANGELOG.md

@@ -4,6 +4,10 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/) and this project adheres to [Semantic Versioning](https://semver.org/).
 
+## [3.0.3] - 2022-05-27
+### Fixed
+* Unable to create new Meganav properties due to null data type
+
 ## [3.0.2] - 2022-05-23
 ### Fixed
 * `meganav-card` styles breaking backoffice minification
@@ -24,6 +28,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/) and this
 * Actions to expand / collapse Meganav, and populate with all nodes from the tree
 * UI overhaul with improved accessibility
 
+## [2.0.3] - 2022-05-27
+### Fixed
+* Unable to create new Meganav properties due to null data type
+
 ## [2.0.2] - 2022-05-23
 ### Fixed
 * `meganav-card` styles breaking backoffice minification
@@ -78,10 +86,12 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/) and this
 ### Added
 * Initial release of Meganav for Umbraco 7.5
 
-[Unreleased]: https://github.com/callumbwhyte/meganav/compare/release-3.0.2...HEAD
+[Unreleased]: https://github.com/callumbwhyte/meganav/compare/release-3.0.3...HEAD
+[3.0.3]: https://github.com/callumbwhyte/meganav/compare/release-3.0.2...release-3.0.3
 [3.0.2]: https://github.com/callumbwhyte/meganav/compare/release-3.0.1...release-3.0.2
 [3.0.1]: https://github.com/callumbwhyte/meganav/compare/release-3.0.0...release-3.0.1
 [3.0.0]: https://github.com/callumbwhyte/meganav/compare/release-2.0.0...release-3.0.0
+[2.0.3]: https://github.com/callumbwhyte/meganav/compare/release-2.0.2...release-2.0.3
 [2.0.2]: https://github.com/callumbwhyte/meganav/compare/release-2.0.1...release-2.0.2
 [2.0.1]: https://github.com/callumbwhyte/meganav/compare/release-2.0.0...release-2.0.1
 [2.0.0]: https://github.com/callumbwhyte/meganav/tree/release-2.0.0

src/Our.Umbraco.Meganav/Migrations/LegacyDataTypeChangingHandler.cs

@@ -25,7 +25,9 @@ public void Handle(DataTypeSavingNotification notification)
                 {
                     var existingEntity = _dataTypeService.GetDataType(x.Id);
 
-                    return existingEntity?.EditorAlias != Constants.PropertyEditorAlias && LegacyEditors.Aliases.Any(existingEntity.EditorAlias.InvariantContains);
+                    return existingEntity != null
+                        && existingEntity.EditorAlias != Constants.PropertyEditorAlias
+                        && LegacyEditors.Aliases.Any(existingEntity.EditorAlias.InvariantContains);
                 });
 
             foreach (var dataType in dataTypes)