bug #6240 Fixed warning in DateTimeFilterType.php (alshenetsky)

This PR was merged into the 4.x branch.

Discussion
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Fixed warning in DateTimeFilterType.php

Fixes #6239

Commits
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c8a4b9f Fixed warning in DateTimeFilterType.php

src/Form/Filter/Type/DateTimeFilterType.php

@@ -33,6 +33,10 @@ public function buildForm(FormBuilderInterface $builder, array $options): void
         $builder->addModelTransformer(new CallbackTransformer(
             static fn ($data) => $data,
             static function ($data) use ($options) {
+                // symfony form will cut off invalid values, so make sure no warnings will be thrown out:
+                $data['value'] ??= null;
+                $data['value2'] ??= null;
+
                 if (ComparisonType::BETWEEN === $data['comparison']) {
                     if (null === $data['value'] || '' === $data['value'] || null === $data['value2'] || '' === $data['value2']) {
                         throw new TransformationFailedException('Two values must be provided when "BETWEEN" comparison is selected.');