fixup! feat!: improve deserialization and production logic

lib/src/core/definitions/extensions/json_parser.dart

@@ -295,22 +295,31 @@ extension ParseField on Map<String, dynamic> {
 
   /// Parses a field with a given [name] as a [Map] of [DataSchema]s.
   ///
-  /// Returns `null` if the field should not be present or if it is not a
-  /// JSON object containing other objects.
+  /// Returns `null` if the field should not be present and throws a
+  /// [FormatException] if it is not a [Map] containing at least a number a
+  /// [minimalSize] of other [Map]s.
   ///
   /// If a [Set] of [parsedFields] is passed to this function, the field [name]
   /// will added. This can be used for filtering when parsing additional fields.
   Map<String, DataSchema>? parseDataSchemaMapField(
     String name,
     PrefixMapping prefixMapping,
-    Set<String>? parsedFields,
-  ) {
+    Set<String>? parsedFields, {
+    int minimalSize = 0,
+  }) {
     final fieldValue = parseField<Map<String, dynamic>>(name, parsedFields);
 
     if (fieldValue == null) {
       return null;
     }
 
+    final length = fieldValue.length;
+    if (fieldValue.length < minimalSize) {
+      throw FormatException(
+          "Expected this Map to contain at least $minimalSize other Map(s), "
+          "got $length.");
+    }
+
     final result = <String, DataSchema>{};
     for (final entry in fieldValue.entries) {
       final value = entry.value;
@@ -390,15 +399,21 @@ extension ParseField on Map<String, dynamic> {
   ///
   /// Adds the key `securityDefinitions` to the set of [parsedFields], if
   /// defined.
-  Map<String, SecurityScheme>? parseSecurityDefinitions(
+  Map<String, SecurityScheme> parseSecurityDefinitions(
     PrefixMapping prefixMapping,
     Set<String> parsedFields,
   ) {
     final fieldValue =
         parseMapField<dynamic>("securityDefinitions", parsedFields);
 
     if (fieldValue == null) {
-      return null;
+      throw const FormatException("Missing required securityDefinitions field");
+    }
+
+    if (fieldValue.isEmpty) {
+      throw const FormatException(
+        "securityDefinitions has to contain at least one element but is empty.",
+      );
     }
 
     final Map<String, SecurityScheme> result = {};

lib/src/core/definitions/thing_description.dart

@@ -75,10 +75,11 @@ class ThingDescription {
     final security = json.parseRequiredArrayField<String>(
       "security",
       parsedFields: parsedFields,
+      minimalSize: 1,
     );
 
     final securityDefinitions =
-        json.parseSecurityDefinitions(prefixMapping, parsedFields) ?? {};
+        json.parseSecurityDefinitions(prefixMapping, parsedFields);
 
     final forms = json.parseForms(prefixMapping, parsedFields);
     // TODO: Move somewhere else