Document issue with Gedmo\DoctrineExtensions (dustin10#1582)

Author: craigh

docs/known_issues.md

@@ -39,6 +39,38 @@ class Product
 
 See issue [GH-123](https://github.com/dustin10/VichUploaderBundle/issues/123)
 
+## Uploading files does not trigger Gedmo/DoctrineExtensions events
+
+Similar to the issue above, because VichUploaderBundle relies on Doctrine's `prePersist` and
+`preUpdate` events which occur _after_ Gedmo's use of the `preFlush` event to execute it's own
+handlers, it is not possible to use Gedmo's handlers to track changes for uploaded files. To be
+more specific, you cannot use `Gedmo\Timestampable` to track when a file is uploaded or changed.
+One solution for this is to update your timestamp property in your setters of the file and field
+properties; updating both is necessary to track delete and change actions.
+
+```php
+    #[Vich\UploadableField(mapping: 'custom_file', fileNameProperty: 'myField')]
+    protected ?File $myFile = null;
+
+    #[ORM\Column(type: Types::STRING, length: 255, nullable: true)]
+    protected ?string $myField = null;
+
+    #[ORM\Column(type: Types::DATETIME_MUTABLE, nullable: true)]
+    public private(set) ?\DateTime $myFieldUpdatedAt = null;
+
+    public function setMyFile(?File $file = null): void
+    {
+        $this->myFieldUpdatedAt = new \DateTime();
+        $this->myFile = $file;
+    }
+
+    public function setMyField(?string $myField = null): void
+    {
+        $this->myFieldUpdatedAt = new \DateTime();
+        $this->myField = $myField;
+    }
+```
+
 ## Image not deleted with cascade deletion and Doctrine
 
 Just check the following options: `cascade={"remove"}` and `orphanRemoval=true`.