Refactor/cubit to notifier migration by aydinguven-leancode · Pull Request #42 · leancodepl/leancode_forms

aydinguven-leancode · 2026-06-19T11:36:51Z

Migration from Cubit to a Value Notifier based state management
Dropped dependencies: flutter_bloc, rx_dart, flutter_hooks, equatable`
Name changes for relevant classes
Relevant changes on tests and example project

Partially modified Readme.md and Changelog.md files about the above migration
Introduced Migration.md file
Added a few more examples as well as short descriptions to each example page

…nagement Migrated from Cubit (Bloc) to value notifier. Removed dependencies: flutter_bloc, rx_dart, equatable, Changes are reflected on examples Changes are reflected on tests

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Albert221 · 2026-06-19T12:10:16Z

+  });
+
+  /// The focus node of the field.
+  final focusNode = FocusNode();


Use debugLabel

Albert221 · 2026-06-19T12:11:02Z

+import 'package:leancode_forms/leancode_forms.dart';
+
+/// A [TextFieldController] that owns a [FocusNode] for scroll-to-error flows.
+class FocusableTextFieldController<E extends Object>


All form controls are usually focusable, I don't think having a Focusable... wrapper for each of the ...FieldController is a good approach

Wait why is it in example and not in the lib itself?

Albert221 · 2026-06-19T12:12:16Z

+
+Side-by-side snippets showing the same form scenario in three flavors:
+
+1. **0.1.x (pre-migration)** — built on `flutter_bloc` + `rxdart`


I don't care about older versions in EXAMPLE. That's what changelog, git history and migration document is for

Albert221 · 2026-06-19T12:13:16Z

+
+1. **0.1.x (pre-migration)** — built on `flutter_bloc` + `rxdart`
+2. **0.2.0 with `FieldBuilder`** — the recommended default; tiny wrapper around `ValueListenableBuilder`
+3. **0.2.0 with `ValueListenableBuilder`** directly — for cases where you want the SDK primitive (e.g. the `child:` optimization)


What's the use-case for having this approach? Looking at just the API I think it would be better and simpler to keep one API for the builders

Albert221 · 2026-06-19T12:14:14Z

+FieldBuilder<String, ValidationError>(
+  field: context.read<SignupController>().email,
+  builder: (context, state) => TextFormField(
+    controller: context.read<SignupController>().email.textController,


We already passed the field controller, why fetch it again? Please just add the field controller itself into the builder callback params.

Albert221 · 2026-06-19T12:14:32Z

+
+// Render:
+FieldBuilder<String, ValidationError>(
+  field: context.read<SignupController>().email,


Using context.read instead of watch/select in build() method is an antipattern

Albert221 · 2026-06-19T12:16:22Z

+  * `FieldCubit` → `FieldController`
+  * `TextFieldCubit` → `TextFieldController`
+  * `BooleanFieldCubit` → `BooleanFieldController`
+  * `SingleSelectFieldCubit` → `SingleSelectFieldController`
+  * `MultiSelectFieldCubit` → `MultiSelectFieldController`
+  * `FormGroupCubit` → `FormGroupController`


I'm not a fan of the ...Controller naming. It's too close to TextEditingController. I'd suggest maybe Form...Field like FormBooleanField or FormTextField

PiotrRogulski · 2026-06-19T11:57:07Z

  flutter_test:
    sdk: flutter
-  leancode_lint: ^15.0.0
+  leancode_lint: ^15.0.0


Keep final newline

PiotrRogulski · 2026-06-19T12:00:03Z

+/// to be able to unambiguously detect lack of errors.
+///
+/// If autovalidate is true, the validator will be run after each field change.
+// ignore_for_file: avoid_positional_boolean_parameters


This package depends on leancode_lint 15, which has this lint disabled (in version 14) – no need to ignore it, I think

PiotrRogulski · 2026-06-19T12:00:39Z

+///
+/// Introducing cycles in forms is not supported and not checked against (most
+/// likely will cause a stack overflow somewhere).
+// ignore_for_file: avoid_positional_boolean_parameters


PiotrRogulski · 2026-06-19T12:02:39Z

+/// If autovalidate is true, the validator will be run after each field change.
+// ignore_for_file: avoid_positional_boolean_parameters
+class FieldController<T, E extends Object>
+    extends ValueNotifier<FieldState<T, E>> {


Do we want to extend ValueNotifier directly, instead of e.g. ValueListenable and adding our own value field? ValueNotifier exposes a public setter, so that anyone can create and set arbitrary FieldState values

PiotrRogulski · 2026-06-19T12:03:54Z

+  /// The current state. Alias for [value] kept for readability at call sites
+  /// that previously read `cubit.state`.
+  FieldState<T, E> get state => value;


I wouldn't do that tbh. The entire undertaking is extremely breaking anyway, so I don't see a value in keeping a bloc-related alias

PiotrRogulski · 2026-06-19T12:08:30Z

+            ...controller.deliveryList.map(
+              (e) => ConsumerSubform(
+                key: ValueKey(e.hashCode),
+                form: e,
+                onRemove: controller.removeConsumer,
+              ),
+            ),


Use a for loop

PiotrRogulski · 2026-06-19T12:09:22Z

+      child: SingleChildScrollView(
+        child: Column(


SingleChildScrollView + Column -> ListView?

PiotrRogulski · 2026-06-19T12:14:12Z

  flutter_test:
    sdk: flutter
-  leancode_lint: ^15.0.0
+  leancode_lint: ^6.0.0


Why such a downgrade?

cupofme · 2026-06-19T12:29:36Z

+/// Introducing cycles in forms is not supported and not checked against (most
+/// likely will cause a stack overflow somewhere).
+// ignore_for_file: avoid_positional_boolean_parameters
+class FormGroupController extends ValueNotifier<FormGroupState> {


Why does entity called FormGroupController manages entities called FieldController? Naming looks a bit inconsistent to me

cupofme · 2026-06-19T12:45:50Z

+```dart
+class SimpleFormController extends FormGroupController {
+  SimpleFormController() {
+    registerFields([firstName, email]);


Can it be an abstract getter fields in FormGroupController that needs to be implemented in subclasses? This way it'll be required and therefore one less thing that can be forgotten.

Something like this:

class SimpleFormController extends FormGroupController { SimpleFormController(); @override List<FieldController> get fields => [ firstName, email, ]; ... }

Having registerFields allows dynamically adding fields as needed (for example, conditional fields). Although for that, an unregisterFields method would be needed 🤔

PiotrRogulski · 2026-06-19T14:02:24Z

+    addTearDown(controller.dispose);
+
+    controller.email.setValue('john@email.com');
+    await Future<void>.delayed(const Duration(seconds: 2));


It would be nice to have a way to "await validation"

PiotrRogulski · 2026-06-19T14:07:45Z

+          const ListEquality<FieldController<dynamic, dynamic>>()
+              .equals(fields, other.fields) &&
+          const SetEquality<FormGroupController>()
+              .equals(subforms, other.subforms) &&


Consider using listEquals and setEquals from Flutter

aydinguven-leancode and others added 4 commits June 19, 2026 09:57

[LMG-394] Migration from Cubit to Value Notifier based field state ma…

1f42255

…nagement Migrated from Cubit (Bloc) to value notifier. Removed dependencies: flutter_bloc, rx_dart, equatable, Changes are reflected on examples Changes are reflected on tests

[LMG-404] updated readme.md and changelog entries on LMG-394

b0203ec

Potential fix for pull request finding

c27ab28

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Potential fix for pull request finding

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Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Albert221 reviewed Jun 19, 2026

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PiotrRogulski reviewed Jun 19, 2026

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cupofme reviewed Jun 19, 2026

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PiotrRogulski reviewed Jun 19, 2026

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		Side-by-side snippets showing the same form scenario in three flavors:

		1. 0.1.x (pre-migration) — built on `flutter_bloc` + `rxdart`

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aydinguven-leancode commented Jun 19, 2026

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cupofme Jun 19, 2026 •

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