[Live] Ignore problems with writing bad types for writable paths

The motivating use-case is where you have a writable property that starts
null but the setter method does NOT allow null. When that null is rehydrated later,
we attempt to call the setter with a null value, which explodes.

This makes for a better UX... though with a sprinkle of magic to make it happen.

src/LiveComponent/src/LiveComponentHydrator.php

@@ -159,7 +159,8 @@ public function hydrate(object $component, array $props, array $updatedProps, Li
             );
 
             /*
-             | 2) Set UPDATED "writable paths" data for this LiveProp.
+             | 2) Set ORIGINAL "writable paths" data for this LiveProp.
+             | (which may represent data that was updated on a previous request)
              */
             $originalWritablePaths = $this->calculateWritablePaths($propMetadata, $propertyValue, $dehydratedOriginalProps, $frontendName, \get_class($component));
             $propertyValue = $this->setWritablePaths(
@@ -194,16 +195,12 @@ public function hydrate(object $component, array $props, array $updatedProps, Li
              | 4) Set UPDATED "writable paths" data for this LiveProp.
              */
             $updatedWritablePaths = $this->calculateWritablePaths($propMetadata, $propertyValue, $dehydratedUpdatedProps, $frontendName, \get_class($component));
-            try {
-                $propertyValue = $this->setWritablePaths(
-                    $updatedWritablePaths,
-                    $frontendName,
-                    $propertyValue,
-                    $dehydratedUpdatedProps,
-                );
-            } catch (HydrationException $e) {
-                // swallow this: it's bad data from the user
-            }
+            $propertyValue = $this->setWritablePaths(
+                $updatedWritablePaths,
+                $frontendName,
+                $propertyValue,
+                $dehydratedUpdatedProps,
+            );
 
             try {
                 $this->propertyAccessor->setValue($component, $propMetadata->getName(), $propertyValue);
@@ -316,7 +313,10 @@ private function setWritablePaths(array $writablePaths, string $frontendPropName
                     $writablePathData
                 );
             } catch (PropertyAccessExceptionInterface $exception) {
-                throw new HydrationException(sprintf('The model "%s.%s" was sent for update, but it could not be set: %s', $frontendPropName, $writablePath, $exception->getMessage()), $exception);
+                // The user likely sent bad data (e.g. string for a number field).
+                // Simply fail to set the field and use the previous value
+                // (this can also happen with original, writable data - e.g. if
+                // a property is "null", but the setter method doesn't allow null).
             }
         }
 

src/LiveComponent/tests/Fixtures/Entity/CategoryFixtureEntity.php

@@ -0,0 +1,47 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\UX\LiveComponent\Tests\Fixtures\Entity;
+
+use Doctrine\ORM\Mapping as ORM;
+
+/**
+ * @ORM\Entity
+ */
+class CategoryFixtureEntity
+{
+    /**
+     * @ORM\Id
+     * @ORM\GeneratedValue
+     * @ORM\Column(type="integer")
+     */
+    private ?int $id = null;
+
+    /**
+     * @ORM\Column(type="string")
+     */
+    private ?string $name = null;
+
+    public function getId(): ?int
+    {
+        return $this->id;
+    }
+
+    public function getName(): ?string
+    {
+        return $this->name;
+    }
+
+    public function setName(string $name)
+    {
+        $this->name = $name;
+    }
+}

src/LiveComponent/tests/Integration/LiveComponentHydratorTest.php

@@ -23,6 +23,7 @@
 use Symfony\UX\LiveComponent\Tests\Fixtures\Dto\Embeddable2;
 use Symfony\UX\LiveComponent\Tests\Fixtures\Dto\Money;
 use Symfony\UX\LiveComponent\Tests\Fixtures\Dto\Temperature;
+use Symfony\UX\LiveComponent\Tests\Fixtures\Entity\CategoryFixtureEntity;
 use Symfony\UX\LiveComponent\Tests\Fixtures\Entity\Embeddable1;
 use Symfony\UX\LiveComponent\Tests\Fixtures\Entity\Entity1;
 use Symfony\UX\LiveComponent\Tests\Fixtures\Entity\Entity2;
@@ -1066,6 +1067,19 @@ public function provideInvalidHydrationTests(): iterable
                     $this->assertSame(1, $object->nonNullableInt->value);
                 });
         }, 80100];
+
+        yield 'writable_path_with_type_problem_ignored' => [function () {
+            return HydrationTest::create(new class() {
+                #[LiveProp(writable: ['name'])]
+                public CategoryFixtureEntity $category;
+            })
+                ->mountWith(['category' => new CategoryFixtureEntity()])
+                ->assertObjectAfterHydration(function (object $object) {
+                    // dehydrating category.name=null does not cause issues
+                    // even though setName() does not allow null
+                    $this->assertNull($object->category->getName());
+                });
+        }];
     }
 
     public function testHydrationFailsIfChecksumMissing(): void