fix: serverOnly + one-to-one id relation regression on main (serverpod#3243)

Author: nielsenko

tools/serverpod_cli/lib/src/analyzer/models/checker/analyze_checker.dart

@@ -3,12 +3,6 @@ import 'package:serverpod_cli/src/analyzer/models/validation/keywords.dart';
 import 'package:yaml/yaml.dart';
 
 class AnalyzeChecker {
-  static bool isIdType(dynamic type) {
-    if (type is! String) return false;
-
-    return type == 'int' || type == 'int?';
-  }
-
   static bool isParentDefined(dynamic node) {
     if (node is! YamlMap) return false;
     return node.containsKey(Keyword.parent);

tools/serverpod_cli/lib/src/analyzer/models/definitions.dart

@@ -359,7 +359,7 @@ class ResolvedInheritanceDefinition extends InheritanceDefinition {
   ResolvedInheritanceDefinition(this.classDefinition);
 }
 
-abstract class RelationDefinition {
+sealed class RelationDefinition {
   String? name;
 
   bool isForeignKeyOrigin;

tools/serverpod_cli/lib/src/analyzer/models/validation/restrictions.dart

@@ -731,35 +731,38 @@ class Restrictions {
     dynamic content,
     SourceSpan? span,
   ) {
-    var errors = <SourceSpanSeverityException>[];
-    var definition = documentDefinition;
-
-    if (definition is! ClassDefinition) return errors;
+    var classDefinition = documentDefinition;
+    if (classDefinition is! ClassDefinition) return const [];
 
-    var field = definition.findField(parentNodeName);
-    if (field == null) return errors;
-    var type = field.type.className;
+    var field = classDefinition.findField(parentNodeName);
+    if (field == null) return const [];
 
-    if (AnalyzeChecker.isIdType(type) &&
-        !AnalyzeChecker.isParentDefined(content)) {
-      errors.add(SourceSpanSeverityException(
-        'The "parent" property must be defined on id fields.',
-        span,
-      ));
+    var type = field.type;
+    if (type.isIdType && !AnalyzeChecker.isParentDefined(content)) {
+      return [
+        SourceSpanSeverityException(
+          'The "parent" property must be defined on id fields.',
+          span,
+        )
+      ];
     }
 
-    if (!AnalyzeChecker.isFieldDefined(content)) {
-      var isOptional = AnalyzeChecker.isOptionalDefined(content);
-      var isServerOnly = field.scope == ModelFieldScopeDefinition.serverOnly;
-      if (isServerOnly && !isOptional) {
-        errors.add(SourceSpanSeverityException(
+    var relation = field.relation;
+    if (relation is! ObjectRelationDefinition) return const [];
+
+    if (!AnalyzeChecker.isFieldDefined(content) &&
+        !classDefinition.serverOnly &&
+        field.scope == ModelFieldScopeDefinition.serverOnly &&
+        !relation.nullableRelation) {
+      return [
+        SourceSpanSeverityException(
           'The relation with scope "${field.scope.name}" requires the relation to be optional.',
           span,
-        ));
-      }
+        )
+      ];
     }
 
-    return errors;
+    return const [];
   }
 
   List<SourceSpanSeverityException> validateParentName(

tools/serverpod_cli/test/analyzer/models/stateful_analyzer/model_validation/relation/relation_manual_field_test.dart

@@ -328,10 +328,10 @@ fields:
       test(
           'then the error message reports that the "optional" property '
           'is mutually exclusive with the "field" property.', () {
-        var error = errors.first;
         expect(
-          error.message,
-          'The "optional" property is mutually exclusive with the "field" property.',
+          errors.map((e) => e.message),
+          contains(
+              'The "optional" property is mutually exclusive with the "field" property.'),
         );
       });
     },