Allow to customize the string representation of Collection field entries

doc/fields/CollectionField.rst

@@ -145,14 +145,22 @@ used to render the form of each collection entry::
     yield CollectionField::new('...')->setEntryType(SomeType::class);
 
 setEntryToStringMethod
-~~~~~~~~~~~~
+~~~~~~~~~~~~~~~~~~~~~~
 
 By default, items in the collection are represented by a single line showing
-their ``__toString()`` value. The ``setEntryToStringMethod()`` method defines the method
-used to get string value of each item::
+their ``__toString()`` value. Use this option to define how to get the string
+representation of each collection entry::
 
+    // this calls the 'getFullName()' method in the entity
     yield CollectionField::new('...')->setEntryToStringMethod('getFullName');
 
+    // you can also pass a callable to generate the string
+    yield CollectionField::new('...')->setEntryToStringMethod(fn (): string => '...');
+    // your callable receives the entity and the translator service as arguments
+    yield CollectionField::new('...')->setEntryToStringMethod(
+        fn (Category $value, TranslatorInterface $translator): string => $translator->trans($value->getDescription())
+    );
+
 showEntryLabel
 ~~~~~~~~~~~~~~
 

src/Field/CollectionField.php

@@ -84,7 +84,10 @@ public function setEntryType(string $formTypeFqcn): self
         return $this;
     }
 
-    public function setEntryToStringMethod(string $toStringMethod): self
+    /**
+     * @param string|callable $toStringMethod Either a string with the name of the method to call in the entry object or a callable to generate the string representation of the entry. The callable is passed the value as the first argument and the translator service as the second argument.
+     */
+    public function setEntryToStringMethod(string|callable $toStringMethod): self
     {
         $this->setCustomOption(self::OPTION_ENTRY_TO_STRING_METHOD, $toStringMethod);
 

src/Twig/EasyAdminTwigExtension.php

@@ -14,7 +14,6 @@
 use Symfony\Contracts\Translation\TranslatableInterface;
 use Symfony\Contracts\Translation\TranslatorInterface;
 use Twig\Environment;
-use Twig\Error\RuntimeError;
 use Twig\Extension\AbstractExtension;
 use Twig\Extension\GlobalsInterface;
 use Twig\TwigFilter;
@@ -134,8 +133,21 @@ public function applyFilterIfExists(Environment $environment, $value, string $fi
         throw new RuntimeError(sprintf('Invalid callback for filter: "%s"', $filterName));
     }
 
-    public function representAsString($value, ?string $toStringMethod = null): string
+    public function representAsString($value, string|callable|null $toStringMethod = null): string
     {
+        if (null !== $toStringMethod) {
+            if (\is_callable($toStringMethod)) {
+                return $toStringMethod($value, $this->translator);
+            }
+
+            $callable = [$value, $toStringMethod];
+            if (!\is_callable($callable) || !\method_exists($value, $toStringMethod)) {
+                throw new \RuntimeException(sprintf('The method "%s()" does not exist or is not callable in the value of type "%s"', $toStringMethod, is_object($value) ? \get_class($value) : \gettype($value)));
+            }
+
+            return \call_user_func($callable);
+        }
+
         if (null === $value) {
             return '';
         }

tests/Twig/EasyAdminTwigExtensionTest.php

@@ -0,0 +1,75 @@
+<?php
+
+namespace EasyCorp\Bundle\EasyAdminBundle\Tests\Twig;
+
+use EasyCorp\Bundle\EasyAdminBundle\Provider\AdminContextProvider;
+use EasyCorp\Bundle\EasyAdminBundle\Twig\EasyAdminTwigExtension;
+use Symfony\Bundle\FrameworkBundle\Test\KernelTestCase;
+use Symfony\Component\AssetMapper\ImportMap\ImportMapRenderer;
+use Symfony\Component\DependencyInjection\ServiceLocator;
+use Symfony\Component\Security\Csrf\CsrfTokenManagerInterface;
+use Symfony\Contracts\Translation\TranslatableInterface;
+use Symfony\Contracts\Translation\TranslatorInterface;
+
+class EasyAdminTwigExtensionTest extends KernelTestCase
+{
+    /**
+     * @dataProvider provideValuesForRepresentAsString
+     */
+    public function testRepresentAsString($value, $expectedValue, bool $assertRegex = false, string|callable|null $toStringMethod = null): void
+    {
+        $translator = $this->getMockBuilder(TranslatorInterface::class)->disableOriginalConstructor()->getMock();
+        $translator->method('trans')->willReturnCallback(fn($value) => '*'.$value);
+
+        $extension = new EasyAdminTwigExtension(
+            $this->getMockBuilder(ServiceLocator::class)->disableOriginalConstructor()->getMock(),
+            $this->getMockBuilder(AdminContextProvider::class)->disableOriginalConstructor()->getMock(),
+            $this->getMockBuilder(CsrfTokenManagerInterface::class)->disableOriginalConstructor()->getMock(),
+            $this->getMockBuilder(ImportMapRenderer::class)->disableOriginalConstructor()->getMock(),
+            $translator
+        );
+
+        $result = $extension->representAsString($value, $toStringMethod);
+
+        if ($assertRegex) {
+            $this->assertMatchesRegularExpression($expectedValue, $result);
+        } else {
+            $this->assertSame($expectedValue, $result);
+        }
+    }
+
+    public function testRepresentAsStringExcepion()
+    {
+        $this->expectException(\RuntimeException::class);
+        $this->expectExceptionMessageMatches('/The method "someMethod\(\)" does not exist or is not callable in the value of type "class@anonymous.*"/');
+
+        $extension = new EasyAdminTwigExtension(
+            $this->getMockBuilder(ServiceLocator::class)->disableOriginalConstructor()->getMock(),
+            $this->getMockBuilder(AdminContextProvider::class)->disableOriginalConstructor()->getMock(),
+            $this->getMockBuilder(CsrfTokenManagerInterface::class)->disableOriginalConstructor()->getMock(),
+            $this->getMockBuilder(ImportMapRenderer::class)->disableOriginalConstructor()->getMock(),
+            $this->getMockBuilder(TranslatorInterface::class)->disableOriginalConstructor()->getMock()
+        );
+
+        $extension->representAsString(new class {}, 'someMethod');
+    }
+
+    public function provideValuesForRepresentAsString()
+    {
+        yield [null, ''];
+        yield ['foo bar', 'foo bar'];
+        yield [5, '5'];
+        yield [3.14, '3.14'];
+        yield [true, 'true'];
+        yield [false, 'false'];
+        yield [[1, 2, 3], 'Array (3 items)'];
+        yield [new class implements TranslatableInterface { public function trans(TranslatorInterface $translator, string $locale = null): string { return $translator->trans('some value'); } }, '*some value'];
+        yield [new class {}, '/class@anonymous.*/', true];
+        yield [new class { public function __toString() { return 'foo bar'; }}, 'foo bar'];
+        yield [new class { public function getId() { return 1234; }}, '/class@anonymous.* #1234/', true];
+
+        yield ['foo', 'foo bar', false, fn($value) => $value.' bar'];
+        yield ['foo', '*foo bar', false, fn($value, $translator) => $translator->trans($value.' bar')];
+        yield [new class () { public function someMethod() { return 'foo'; }}, 'foo', false, 'someMethod'];
+    }
+}