Return value type error

[pimago]

Description

When the entry form is not filled correctly I get an error page instead of the error list.
I rebuild a simplified version and still get the same error.
It was working fine a few months ago.

This is my simplified code

{# Macro to help output errors: #}
{% macro errorList(errors) %}
	 {% if errors %}
		  {{ ul(errors, { class: 'errors' }) }}
	 {% endif %}
{% endmacro %}

{# Default value for the `entry` variable: #}
{% set guestEntry = guestEntry ?? null %}

<form method="post" action="" accept-charset="UTF-8">
	 {# Hidden inputs required for the form to work: #}
	 {{ csrfInput() }}
	 {{ actionInput('guest-entries/save') }}
	 {% set path = craft.app.request.fullUri %}
	 {{ redirectInput('/' ~ path) }}
	 {{ hiddenInput('sectionHandle', 'entrants') }}

	 {# Entry properties and custom fields: #}
	 <label for="title">Name</label>
	 {{ input('text', 'title', guestEntry ? guestEntry.title, { id: 'title' }) }}
	 {{ guestEntry ? _self.errorList(guestEntry.getErrors('title')) }}

	 <label for="email">Email</label>
	 {{ input('email', 'fields[email]', guestEntry ? guestEntry.email, { id: 'email' }) }}
	 {{ guestEntry ? _self.errorList(guestEntry.getErrors('email')) }}

	 <input id="privacy" type="hidden" name="fields[plainText]" value="1">

	 <button type="submit">Publish</button>
</form>

And this is the error

TypeError: craft\guestentries\controllers\SaveController::_returnError(): Return value must be of type yii\web\Response, null returned in /var/www/html/vendor/craftcms/guest-entries/src/controllers/SaveController.php:192
Stack trace:
#0 /var/www/html/vendor/craftcms/guest-entries/src/controllers/SaveController.php(142): craft\guestentries\controllers\SaveController->_returnError(Object(craft\guestentries\models\Settings), Object(craft\elements\Entry))
#1 [internal function]: craft\guestentries\controllers\SaveController->actionIndex()
#2 /var/www/html/vendor/yiisoft/yii2/base/InlineAction.php(57): call_user_func_array(Array, Array)
#3 /var/www/html/vendor/yiisoft/yii2/base/Controller.php(178): yii\base\InlineAction->runWithParams(Array)
#4 /var/www/html/vendor/yiisoft/yii2/base/Module.php(552): yii\base\Controller->runAction('', Array)
#5 /var/www/html/vendor/craftcms/cms/src/web/Application.php(341): yii\base\Module->runAction('guest-entries/s...', Array)
#6 /var/www/html/vendor/craftcms/cms/src/web/Application.php(642): craft\web\Application->runAction('guest-entries/s...', Array)
#7 /var/www/html/vendor/craftcms/cms/src/web/Application.php(303): craft\web\Application->_processActionRequest(Object(craft\web\Request))
#8 /var/www/html/vendor/yiisoft/yii2/base/Application.php(384): craft\web\Application->handleRequest(Object(craft\web\Request))
#9 /var/www/html/web/index.php(26): yii\base\Application->run()
#10 {main}

Additional info

• Craft version: 4.8.9
• PHP version: 8.0.30
• Database driver & version: MariaDB 10.3.39
• Plugins & versions: Guest Entries 4.0.0

[pimago]

I tested this on a new Craft 5 site. I installed Guest Entries. Copied the Guest Entries usage sample code (minus the body field) to a test template and submitted an empty form. This will get me the same error as above. If I fill out the title field a new entry is created. Turning the Validate setting off or on doesn't seem to make any difference. Am I overlooking something regarding the validation?

[olivierbon]

Thanks for reporting! I just raised a PR with a fix for this.

[angrybrad]

Just released 4.0.1 with this fix. Thanks, all!