bug #6221 Fix InvalidOptionsException when using ChoiceField with zer…

…o choices (alshenetsky)

This PR was merged into the 4.x branch.

Discussion
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Fix InvalidOptionsException when using ChoiceField with zero choices

fix #6220

Commits
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ab54edb fix #6220

src/Field/Configurator/ChoiceConfigurator.php

@@ -65,7 +65,7 @@ public function configure(FieldDto $field, EntityDto $entityDto, AdminContext $c
                 $areChoicesTranslatable = $choicesSupportTranslatableInterface = true;
             }
 
-            if ($allChoicesAreEnums && array_is_list($choices)) {
+            if ($allChoicesAreEnums && array_is_list($choices) && \count($choices) > 0) {
                 $processedEnumChoices = [];
                 foreach ($choices as $choice) {
                     $processedEnumChoices[$choice->name] = $choice;