[go_router_builder] Add a fallback for a not null List or Set param (#…

…8349)

fix issue:  flutter/flutter#149675 

## Pre-launch Checklist

- [ ] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [ ] I read the [Tree Hygiene] page, which explains my
responsibilities.
- [ ] I read and followed the [relevant style guides] and ran the
auto-formatter. (Unlike the flutter/flutter repo, the flutter/packages
repo does use `dart format`.)
- [ ] I signed the [CLA].
- [ ] The title of the PR starts with the name of the package surrounded
by square brackets, e.g. `[shared_preferences]`
- [ ] I [linked to at least one issue that this PR fixes] in the
description above.
- [ ] I updated `pubspec.yaml` with an appropriate new version according
to the [pub versioning philosophy], or this PR is [exempt from version
changes].
- [ ] I updated `CHANGELOG.md` to add a description of the change,
[following repository CHANGELOG style], or this PR is [exempt from
CHANGELOG changes].
- [ ] I updated/added relevant documentation (doc comments with `///`).
- [ ] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [ ] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/packages/blob/main/CONTRIBUTING.md
[Tree Hygiene]:
https://github.com/flutter/flutter/blob/master/docs/contributing/Tree-hygiene.md
[relevant style guides]:
https://github.com/flutter/packages/blob/main/CONTRIBUTING.md#style
[CLA]: https://cla.developers.google.com/
[Discord]:
https://github.com/flutter/flutter/blob/master/docs/contributing/Chat.md
[linked to at least one issue that this PR fixes]:
https://github.com/flutter/flutter/blob/master/docs/contributing/Tree-hygiene.md#overview
[pub versioning philosophy]: https://dart.dev/tools/pub/versioning
[exempt from version changes]:
https://github.com/flutter/flutter/blob/master/docs/ecosystem/contributing/README.md#version
[following repository CHANGELOG style]:
https://github.com/flutter/flutter/blob/master/docs/ecosystem/contributing/README.md#changelog-style
[exempt from CHANGELOG changes]:
https://github.com/flutter/flutter/blob/master/docs/ecosystem/contributing/README.md#changelog
[test-exempt]:
https://github.com/flutter/flutter/blob/master/docs/contributing/Tree-hygiene.md#tests

packages/go_router_builder/CHANGELOG.md

@@ -1,3 +1,8 @@
+
+## 2.7.3
+
+- Fixes an issue when using a not null List or Set param.
+
 ## 2.7.2
 
 - Supports the latest `package:analyzer` and `package:source_gen`.

packages/go_router_builder/lib/src/type_helpers.dart

@@ -273,18 +273,27 @@ class _TypeHelperIterable extends _TypeHelper {
 
       // get correct type for iterable
       String iterableCaster = '';
+      String fallBack = '';
       if (const TypeChecker.fromRuntime(List)
           .isAssignableFromType(parameterElement.type)) {
         iterableCaster = '.toList()';
+        if (!parameterElement.type.isNullableType &&
+            !parameterElement.hasDefaultValue) {
+          fallBack = '?? const []';
+        }
       } else if (const TypeChecker.fromRuntime(Set)
           .isAssignableFromType(parameterElement.type)) {
         iterableCaster = '.toSet()';
+        if (!parameterElement.type.isNullableType &&
+            !parameterElement.hasDefaultValue) {
+          fallBack = '?? const {}';
+        }
       }
 
       return '''
 state.uri.queryParametersAll[
         ${escapeDartString(parameterElement.name.kebab)}]
-        ?.map($entriesTypeDecoder)$iterableCaster''';
+        ?.map($entriesTypeDecoder)$iterableCaster$fallBack''';
     }
     return '''
 state.uri.queryParametersAll[${escapeDartString(parameterElement.name.kebab)}]''';

packages/go_router_builder/pubspec.yaml

@@ -2,7 +2,7 @@ name: go_router_builder
 description: >-
   A builder that supports generated strongly-typed route helpers for
   package:go_router
-version: 2.7.2
+version: 2.7.3
 repository: https://github.com/flutter/packages/tree/main/packages/go_router_builder
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+go_router_builder%22
 

packages/go_router_builder/test_inputs/list.dart

@@ -0,0 +1,17 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:go_router/go_router.dart';
+
+@TypedGoRoute<ListRoute>(path: '/list-route')
+class ListRoute extends GoRouteData {
+  ListRoute({
+    required this.ids,
+    this.nullableIds,
+    this.idsWithDefaultValue = const <int>[0],
+  });
+  final List<int> ids;
+  final List<int>? nullableIds;
+  final List<int> idsWithDefaultValue;
+}

packages/go_router_builder/test_inputs/list.dart.expect

@@ -0,0 +1,40 @@
+RouteBase get $listRoute => GoRouteData.$route(
+      path: '/list-route',
+      factory: $ListRouteExtension._fromState,
+    );
+
+extension $ListRouteExtension on ListRoute {
+  static ListRoute _fromState(GoRouterState state) => ListRoute(
+        ids: state.uri.queryParametersAll['ids']?.map(int.parse).toList() ??
+            const [],
+        nullableIds: state.uri.queryParametersAll['nullable-ids']
+            ?.map(int.parse)
+            .toList(),
+        idsWithDefaultValue: state
+                .uri.queryParametersAll['ids-with-default-value']
+                ?.map(int.parse)
+                .toList() ??
+            const <int>[0],
+      );
+
+  String get location => GoRouteData.$location(
+        '/list-route',
+        queryParams: {
+          'ids': ids.map((e) => e.toString()).toList(),
+          if (nullableIds != null)
+            'nullable-ids': nullableIds?.map((e) => e.toString()).toList(),
+          if (idsWithDefaultValue != const <int>[0])
+            'ids-with-default-value':
+                idsWithDefaultValue.map((e) => e.toString()).toList(),
+        },
+      );
+
+  void go(BuildContext context) => context.go(location);
+
+  Future<T?> push<T>(BuildContext context) => context.push<T>(location);
+
+  void pushReplacement(BuildContext context) =>
+      context.pushReplacement(location);
+
+  void replace(BuildContext context) => context.replace(location);
+}

packages/go_router_builder/test_inputs/set.dart

@@ -0,0 +1,17 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:go_router/go_router.dart';
+
+@TypedGoRoute<SetRoute>(path: '/set-route')
+class SetRoute extends GoRouteData {
+  SetRoute({
+    required this.ids,
+    this.nullableIds,
+    this.idsWithDefaultValue = const <int>{0},
+  });
+  final Set<int> ids;
+  final Set<int>? nullableIds;
+  final Set<int> idsWithDefaultValue;
+}

packages/go_router_builder/test_inputs/set.dart.expect

@@ -0,0 +1,40 @@
+RouteBase get $setRoute => GoRouteData.$route(
+      path: '/set-route',
+      factory: $SetRouteExtension._fromState,
+    );
+
+extension $SetRouteExtension on SetRoute {
+  static SetRoute _fromState(GoRouterState state) => SetRoute(
+        ids: state.uri.queryParametersAll['ids']?.map(int.parse).toSet() ??
+            const {},
+        nullableIds: state.uri.queryParametersAll['nullable-ids']
+            ?.map(int.parse)
+            .toSet(),
+        idsWithDefaultValue: state
+                .uri.queryParametersAll['ids-with-default-value']
+                ?.map(int.parse)
+                .toSet() ??
+            const <int>{0},
+      );
+
+  String get location => GoRouteData.$location(
+        '/set-route',
+        queryParams: {
+          'ids': ids.map((e) => e.toString()).toList(),
+          if (nullableIds != null)
+            'nullable-ids': nullableIds?.map((e) => e.toString()).toList(),
+          if (idsWithDefaultValue != const <int>{0})
+            'ids-with-default-value':
+                idsWithDefaultValue.map((e) => e.toString()).toList(),
+        },
+      );
+
+  void go(BuildContext context) => context.go(location);
+
+  Future<T?> push<T>(BuildContext context) => context.push<T>(location);
+
+  void pushReplacement(BuildContext context) =>
+      context.pushReplacement(location);
+
+  void replace(BuildContext context) => context.replace(location);
+}