sample on how to recursiveley extract errors

dart/lib/src/error_cause_extractor.dart

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+class CauseExtractor<T> {
+  Object? cause(T error) { return null; }
+}
+
+class ErrorCauseExtractor {
+  ErrorCauseExtractor(this.causeExtractorsByType);
+
+  final Map<Type, CauseExtractor> causeExtractorsByType;
+
+  List<Object> flatten(errorWithCause) {
+    var allErrors = <Object>[];
+    var current = errorWithCause;
+
+    while (current != null) {
+      allErrors.add(current);
+      final causeExtractor = causeExtractorsByType[current.runtimeType];
+      current = causeExtractor?.cause(current);
+    }
+    return allErrors;
+  }
+}

dart/test/error_cause_extractor_test.dart

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+import 'package:sentry/src/error_cause_extractor.dart';
+import 'package:test/test.dart';
+
+void main() {
+  test('flatten', () {
+    final errorC = ErrorC();
+    final errorB = ErrorB(errorC);
+    final errorA = ErrorA(errorB);
+
+    final sut = ErrorCauseExtractor({
+      ErrorA: ErrorACauseExtractor(),
+      ErrorB: ErrorBCauseExtractor()
+    });
+
+    final flattened = sut.flatten(errorA);
+    expect(flattened, [errorA, errorB, errorC]);
+  });
+}
+
+class ErrorA {
+  ErrorA(this.other);
+  final ErrorB? other;
+}
+
+class ErrorB {
+  ErrorB(this.anotherOther);
+  final ErrorC? anotherOther;
+}
+
+class ErrorC {
+  // I am empty inside
+}
+
+class ErrorACauseExtractor implements CauseExtractor<ErrorA> {
+  @override
+  Object? cause(ErrorA error) {
+    return error.other;
+  }
+}
+
+class ErrorBCauseExtractor implements CauseExtractor<ErrorB> {
+  @override
+  Object? cause(ErrorB error) {
+    return error.anotherOther;
+  }
+}