Symfony 3.4 + FOSUserBundle add Error-Message for new custom Field

Question

I have created a new custom field in the UserEntity and therefore an Assert-Validation with a error message. This Message can be displayed with {{ form_errors(form) }} globally but I haven´t found a way to display the error-message linked to the field without overriding the whole form_theme.

{{ form_errors(form.field_name) }} does not work either

Answer 1

The FOSUserBundle mapps the errors by himself.

My Problem was a typo in the field name in the FormType. It should exactly match the variable name in the Entity

Entity

/**
 * Some Comment
 *
 * @ORM\Column(name="field_name", type="array", nullable=true)
 * @Assert\NotBlank(message = "Please select at least one field_name")
 */
protected $fieldName; // Entity variable name

FormType

    $builder->add(
        'fieldName', // Needs to match Entity variable name
        ChoiceType::class,
        array(
            'choices' => array(
                'Some Choice' => '1',
                'Other Choice' => '2',
                '3rd Choice' => '3',
            ),
            'label' => 'form.register.fieldname',
            'translation_domain' => 'user',
            'multiple' => true,
            'expanded' => true,
            'required' => true,
        )
    );