create-form-data-handling

name	create-form-data-handling
description	Create the form data flow layer: DataProvider (loads entity data for edit form), DataHandler (dispatches commands on create/update), error handling, and service registration. This bridges the form layer with the CQRS layer. Read Component/Forms/CONTEXT.md for conventions. Trigger: "create form data handling for {Domain}".
needs	["create-cqrs-commands","create-cqrs-queries","create-form-type"]
produces	{Domain}FormDataProvider + {Domain}FormDataHandler + DI registration
subagent	optional

create-form-data-handling

Read @.ai/Component/Forms/CONTEXT.md for form conventions (IdentifiableObject pattern, service registration).

1. DataProvider

Create src/Core/Form/IdentifiableObject/DataProvider/{Domain}FormDataProvider.php implementing FormDataProviderInterface:

• getData(int $id): array — dispatch Get{Domain}ForEditing query via query bus, map the result DTO to the form's expected array structure
• getDefaultData(): array — return sensible defaults for the create form (empty strings, null IDs, active => true)
• Both methods must return the same array structure — the form type cannot distinguish create from edit
• Multilingual fields: return arrays keyed by integer language ID

Reference: src/Core/Form/IdentifiableObject/DataProvider/TaxFormDataProvider.php (simple)

2. DataHandler

Create src/Core/Form/IdentifiableObject/DataHandler/{Domain}FormDataHandler.php implementing FormDataHandlerInterface:

• create(array $data): mixed — build Add{Domain}Command from $data, dispatch via command bus, return new entity ID
• update(int $id, array $data): void — build Edit{Domain}Command($id), call fluent setters for each field from $data, dispatch
• Map form array keys to command setters: $command->setName($data['name'])
• Multilingual: $command->setLocalizedNames($data['name']) where value is lang-keyed array
• Sub-resource commands dispatched separately (see Forms/CONTEXT.md for dispatch order)

Reference: src/Core/Form/IdentifiableObject/DataHandler/TaxFormDataHandler.php (simple)

3. Error handling

• When !$form->isValid(), re-render the form — Twig displays errors automatically via {{ form_errors(field) }}
• Error handling conventions (server-side validation as source of truth, tab error nav) are in Forms/CONTEXT.md

4. Service registration

Register in the appropriate DI YAML file:

• {Domain}Type — tagged with form.type (usually auto-discovered)
• {Domain}FormDataProvider — with autowire: true, autoconfigure: true
• {Domain}FormDataHandler — with autowire: true, autoconfigure: true
• Service ID naming convention is in Forms/CONTEXT.md
• Verify: php bin/console debug:container | grep {domain}_form

Rules

Conventions (DataProvider/DataHandler roles, service registration, IdentifiableObject pattern) are in Forms/CONTEXT.md. Skill-specific reminder:

• All three services (type, provider, handler) must be registered before wiring the controller