From f8dbec95d4700c741e793d458ce8e3b0ae3d21eb Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Mon, 15 Jun 2026 11:35:41 +0200
Subject: [PATCH 01/17] Add `DatabaseObjectBuilder` with `TagBuilder`
 implementation

Introduces an abstract builder for creating, updating and deleting database objects with a fluent setter API, batched transactional deletes and an `INSERT IGNORE`-style helper. `TagBuilder` is the first concrete implementation.
---
 .../lib/data/DatabaseObjectBuilder.class.php  | 250 ++++++++++++++++++
 .../files/lib/data/tag/TagBuilder.class.php   |  46 ++++
 2 files changed, 296 insertions(+)
 create mode 100644 wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
 create mode 100644 wcfsetup/install/files/lib/data/tag/TagBuilder.class.php

diff --git a/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php b/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
new file mode 100644
index 0000000000..89ec16810f
--- /dev/null
+++ b/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
@@ -0,0 +1,250 @@
+<?php
+
+namespace wcf\data;
+
+use wcf\system\database\exception\DatabaseQueryExecutionException;
+use wcf\system\database\util\PreparedStatementConditionBuilder;
+use wcf\system\exception\ClassNotFoundException;
+use wcf\system\exception\ImplementationException;
+use wcf\system\WCF;
+
+/**
+ * Abstract builder for creating, updating and deleting database objects.
+ *
+ * @author      Marcel Werk
+ * @copyright   2001-2026 WoltLab GmbH
+ * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @since       6.3
+ *
+ * @template TDatabaseObject of DatabaseObject
+ */
+abstract class DatabaseObjectBuilder
+{
+    /**
+     * @var array<string, string|int|float|null>
+     */
+    protected array $properties = [];
+
+    /**
+     * @var array<string, string|int|float|null>
+     */
+    protected array $customProperties = [];
+
+    /**
+     * Use forCreate() or forUpdate() to obtain a builder instance.
+     *
+     * @param ?TDatabaseObject $object
+     */
+    private function __construct(protected readonly ?DatabaseObject $object = null) {}
+
+    /**
+     * Persists the pending changes and returns the resulting database object.
+     *
+     * @return TDatabaseObject
+     */
+    public function save(): DatabaseObject
+    {
+        return new (static::getBaseClass())($this->fastSave());
+    }
+
+    /**
+     * Persists the pending changes and returns the object's identifier without
+     * instantiating the full database object.
+     */
+    public function fastSave(): int|string
+    {
+        if ($this->object !== null) {
+            $this->update();
+
+            return $this->object->getObjectID();
+        }
+
+        return $this->create();
+    }
+
+    /**
+     * Inserts a new row and returns the primary key of the created object.
+     */
+    private function create(): int|string
+    {
+        $keys = $values = '';
+        $statementParameters = [];
+        foreach (array_merge($this->properties, $this->customProperties) as $key => $value) {
+            if ($keys !== '') {
+                $keys .= ',';
+                $values .= ',';
+            }
+
+            $keys .= $key;
+            $values .= '?';
+            $statementParameters[] = $value;
+        }
+
+        $sql = "INSERT INTO " . static::getBaseClass()::getDatabaseTableName() . "
+                            (" . $keys . ")
+                VALUES      (" . $values . ")";
+        $statement = WCF::getDB()->prepare($sql);
+        $statement->execute($statementParameters);
+
+        if (static::getBaseClass()::getDatabaseTableIndexIsIdentity()) {
+            $id = WCF::getDB()->getInsertID(static::getBaseClass()::getDatabaseTableName(), static::getBaseClass()::getDatabaseTableIndexName());
+        } elseif (isset($this->properties[static::getBaseClass()::getDatabaseTableIndexName()])) {
+            $id = $this->properties[static::getBaseClass()::getDatabaseTableIndexName()];
+        } else {
+            throw new \BadMethodCallException("Missing value for '" . static::getBaseClass()::getDatabaseTableIndexName() . "'");
+        }
+
+        return $id;
+    }
+
+    /**
+     * Writes the pending property changes to the existing row.
+     */
+    private function update(): void
+    {
+        if ($this->properties === [] && $this->customProperties === []) {
+            return;
+        }
+
+        $updateSQL = '';
+        $statementParameters = [];
+        foreach (array_merge($this->properties, $this->customProperties) as $key => $value) {
+            if ($updateSQL !== '') {
+                $updateSQL .= ', ';
+            }
+            $updateSQL .= $key . ' = ?';
+            $statementParameters[] = $value;
+        }
+        $statementParameters[] = $this->object->getObjectID();
+
+        $sql = "UPDATE  " . static::getBaseClass()::getDatabaseTableName() . "
+                SET     " . $updateSQL . "
+                WHERE   " . static::getBaseClass()::getDatabaseTableIndexName() . " = ?";
+        $statement = WCF::getDB()->prepare($sql);
+        $statement->execute($statementParameters);
+    }
+
+    /**
+     * Creates a new object, returns null if the row already exists.
+     *
+     * @return ?TDatabaseObject
+     */
+    public function createOrIgnore(): ?DatabaseObject
+    {
+        if ($this->object !== null) {
+            throw new \BadMethodCallException("createOrIgnore() can only be used with forCreate().");
+        }
+
+        try {
+            return $this->save();
+        } catch (DatabaseQueryExecutionException $e) {
+            // Error code 23000 = duplicate key
+            if (\intval($e->getCode()) === 23000 && $e->getDriverCode() === '1062') {
+                return null;
+            }
+
+            throw $e;
+        }
+    }
+
+    /**
+     * Deletes the given database object.
+     *
+     * @param TDatabaseObject $object
+     */
+    public static function delete(DatabaseObject $object): void
+    {
+        static::deleteAll([$object->getObjectID()]);
+    }
+
+    /**
+     * Deletes the rows identified by the given primary keys in batches inside
+     * a single transaction.
+     *
+     * @param (string|int)[] $objectIDs
+     */
+    public static function deleteAll(array $objectIDs = []): void
+    {
+        if ($objectIDs === []) {
+            return;
+        }
+
+        $itemsPerLoop = 1000;
+        $loopCount = \ceil(\count($objectIDs) / $itemsPerLoop);
+
+        WCF::getDB()->beginTransaction();
+        $committed = false;
+        try {
+            for ($i = 0; $i < $loopCount; $i++) {
+                $batchObjectIDs = \array_slice($objectIDs, $i * $itemsPerLoop, $itemsPerLoop);
+
+                $conditionBuilder = new PreparedStatementConditionBuilder();
+                $conditionBuilder->add(static::getBaseClass()::getDatabaseTableIndexName() . ' IN (?)', [$batchObjectIDs]);
+
+                $sql = "DELETE FROM " . static::getBaseClass()::getDatabaseTableName() . "
+                        " . $conditionBuilder;
+                $statement = WCF::getDB()->prepare($sql);
+                $statement->execute($conditionBuilder->getParameters());
+            }
+            WCF::getDB()->commitTransaction();
+            $committed = true;
+        } finally {
+            if (!$committed) {
+                WCF::getDB()->rollBackTransaction();
+            }
+        }
+    }
+
+    /**
+     * Returns a builder instance for inserting a new row.
+     */
+    public static function forCreate(): static
+    {
+        return new (static::class)();
+    }
+
+    /**
+     * Returns a builder instance for updating an existing database object.
+     *
+     * @param TDatabaseObject $object
+     */
+    public static function forUpdate(DatabaseObject $object): static
+    {
+        return new static($object);
+    }
+
+    /**
+     * Resolves the database object class associated with this builder by
+     * stripping the `Builder` suffix from the current class name.
+     *
+     * @return class-string<DatabaseObject>
+     */
+    public static function getBaseClass(): string
+    {
+        if (!\str_ends_with(static::class, 'Builder')) {
+            throw new \LogicException("Builder class '" . static::class . "' must end with the 'Builder' suffix.");
+        }
+
+        $className = \mb_substr(static::class, 0, -7);
+        if (!\class_exists($className)) {
+            throw new ClassNotFoundException($className);
+        }
+
+        if (!\is_subclass_of($className, DatabaseObject::class)) {
+            throw new ImplementationException($className, DatabaseObject::class);
+        }
+
+        return $className;
+    }
+
+    /**
+     * Sets a custom property value that is written alongside the regular
+     * properties when the object is persisted.
+     */
+    public function setCustomProperty(string $name, string|int|float|null $value): static
+    {
+        $this->customProperties[$name] = $value;
+
+        return $this;
+    }
+}
diff --git a/wcfsetup/install/files/lib/data/tag/TagBuilder.class.php b/wcfsetup/install/files/lib/data/tag/TagBuilder.class.php
new file mode 100644
index 0000000000..882ee6f3de
--- /dev/null
+++ b/wcfsetup/install/files/lib/data/tag/TagBuilder.class.php
@@ -0,0 +1,46 @@
+<?php
+
+namespace wcf\data\tag;
+
+use wcf\data\DatabaseObjectBuilder;
+
+/**
+ * Builder for creating, updating and deleting tags.
+ *
+ * @author      Marcel Werk
+ * @copyright   2001-2026 WoltLab GmbH
+ * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @since       6.3
+ *
+ * @extends DatabaseObjectBuilder<Tag>
+ */
+final class TagBuilder extends DatabaseObjectBuilder
+{
+    public function setTagID(int $tagID): static
+    {
+        $this->properties['tagID'] = $tagID;
+
+        return $this;
+    }
+
+    public function setLanguageID(int $languageID): static
+    {
+        $this->properties['languageID'] = $languageID;
+
+        return $this;
+    }
+
+    public function setName(string $name): static
+    {
+        $this->properties['name'] = $name;
+
+        return $this;
+    }
+
+    public function setSynonymFor(Tag $tag): static
+    {
+        $this->properties['synonymFor'] = $tag->tagID;
+
+        return $this;
+    }
+}

From c1ec3a5666026ff2f8c0085014f74a42e9145a66 Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Thu, 25 Jun 2026 19:51:01 +0200
Subject: [PATCH 02/17] Migrate tag forms to `DatabaseObjectBuilder` with
 command and events

Replace the `TagAction`-based persistence in `TagAddForm`/`TagEditForm` with the new `DatabaseObjectBuilder` flow.
---
 .../files/lib/acp/form/TagAddForm.class.php   |  76 +++--
 .../files/lib/acp/form/TagEditForm.class.php  |   2 +-
 .../files/lib/command/tag/CreateTag.class.php |  32 +++
 .../files/lib/command/tag/UpdateTag.class.php |  32 +++
 .../lib/data/DatabaseObjectBuilder.class.php  |  22 ++
 .../files/lib/data/tag/TagBuilder.class.php   |  69 +++++
 .../files/lib/event/tag/TagCreated.class.php  |  21 ++
 .../files/lib/event/tag/TagUpdated.class.php  |  21 ++
 ...bstractDatabaseObjectBuilderForm.class.php | 262 ++++++++++++++++++
 ...atabaseObjectBuilderFormDocument.class.php |  67 +++++
 .../builder/field/AbstractFormField.class.php |  21 ++
 .../AbstractFormFieldDecorator.class.php      |  14 +
 .../form/builder/field/IFormField.class.php   |  32 +++
 13 files changed, 642 insertions(+), 29 deletions(-)
 create mode 100644 wcfsetup/install/files/lib/command/tag/CreateTag.class.php
 create mode 100644 wcfsetup/install/files/lib/command/tag/UpdateTag.class.php
 create mode 100644 wcfsetup/install/files/lib/event/tag/TagCreated.class.php
 create mode 100644 wcfsetup/install/files/lib/event/tag/TagUpdated.class.php
 create mode 100644 wcfsetup/install/files/lib/form/AbstractDatabaseObjectBuilderForm.class.php
 create mode 100644 wcfsetup/install/files/lib/system/form/builder/DatabaseObjectBuilderFormDocument.class.php

diff --git a/wcfsetup/install/files/lib/acp/form/TagAddForm.class.php b/wcfsetup/install/files/lib/acp/form/TagAddForm.class.php
index 64e8f14f59..09d249ee92 100644
--- a/wcfsetup/install/files/lib/acp/form/TagAddForm.class.php
+++ b/wcfsetup/install/files/lib/acp/form/TagAddForm.class.php
@@ -2,13 +2,17 @@
 
 namespace wcf\acp\form;
 
+use wcf\command\tag\CreateTag;
+use wcf\command\tag\UpdateTag;
+use wcf\data\DatabaseObjectBuilder;
 use wcf\data\IStorableObject;
 use wcf\data\tag\Tag;
-use wcf\data\tag\TagAction;
+use wcf\data\tag\TagBuilder;
 use wcf\data\tag\TagList;
-use wcf\form\AbstractFormBuilderForm;
+use wcf\form\AbstractDatabaseObjectBuilderForm;
 use wcf\system\form\builder\container\FormContainer;
 use wcf\system\form\builder\data\processor\CustomFormDataProcessor;
+use wcf\system\form\builder\field\IFormField;
 use wcf\system\form\builder\field\SingleSelectionFormField;
 use wcf\system\form\builder\field\tag\TagFormField;
 use wcf\system\form\builder\field\TextFormField;
@@ -27,9 +31,9 @@
  * @copyright   2001-2024 WoltLab GmbH
  * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
  *
- * @extends AbstractFormBuilderForm<Tag>
+ * @extends AbstractDatabaseObjectBuilderForm<Tag, TagBuilder>
  */
-class TagAddForm extends AbstractFormBuilderForm
+class TagAddForm extends AbstractDatabaseObjectBuilderForm
 {
     /**
      * @inheritDoc
@@ -49,15 +53,30 @@ class TagAddForm extends AbstractFormBuilderForm
     /**
      * @inheritDoc
      */
-    public $objectActionClass = TagAction::class;
+    public string $objectEditLinkController = TagEditForm::class;
 
-    /**
-     * @inheritDoc
-     */
-    public $objectEditLinkController = TagEditForm::class;
+    #[\Override]
+    protected function getDatabaseObjectBuilder(): TagBuilder
+    {
+        if ($this->formObject !== null) {
+            return TagBuilder::forUpdate($this->formObject);
+        }
+
+        return TagBuilder::forCreate();
+    }
 
     #[\Override]
-    protected function createForm()
+    protected function getCommand(DatabaseObjectBuilder $builder): callable
+    {
+        if ($this->formObject !== null) {
+            return new UpdateTag($builder);
+        }
+
+        return new CreateTag($builder);
+    }
+
+    #[\Override]
+    protected function createForm(): void
     {
         parent::createForm();
 
@@ -70,12 +89,17 @@ protected function createForm()
                         ->label('wcf.global.name')
                         ->required()
                         ->maximumLength(\TAGGING_MAX_TAG_LENGTH)
+                        ->saveValueCallback(
+                            static fn(TagBuilder $builder, IFormField $field) => $builder->setName(
+                                \str_replace(',', '', StringUtil::trim($field->getSaveValue()))
+                            )
+                        )
                         ->addValidator(
                             new FormFieldValidator('duplicateTagValidator', function (TextFormField $field) {
                                 $languageIDFormField = $field->getDocument()->getFormField('languageID');
                                 $languageID = $languageIDFormField->getValue();
 
-                                $tag = Tag::getTag($field->getValue(), $languageID);
+                                $tag = Tag::getTag($field->getValue(), $languageID ?? 0);
                                 if ($tag !== null && $tag->tagID !== $this->formObject?->tagID) {
                                     $field->addValidationError(
                                         new FormFieldValidationError(
@@ -92,10 +116,20 @@ protected function createForm()
                         ->options($contentLanguages)
                         ->value(isset($contentLanguages[WCF::getLanguage()->languageID]) ? WCF::getLanguage()->languageID : null)
                         ->immutable($this->formAction !== 'create')
-                        ->required(),
+                        ->required()
+                        ->saveValueCallback(
+                            static fn(TagBuilder $builder, IFormField $field) => $builder->setLanguageID(
+                                (int)$field->getSaveValue()
+                            )
+                        ),
                     TagFormField::create('synonyms')
                         ->available($this->formObject?->synonymFor === null)
-                        ->label('wcf.acp.tag.synonyms'),
+                        ->label('wcf.acp.tag.synonyms')
+                        ->saveValueCallback(
+                            static fn(TagBuilder $builder, IFormField $field) => $builder->setSynonyms(
+                                $field->getSaveValue() ?? []
+                            )
+                        ),
                     TemplateFormNode::create('tagSynonymFor')
                         ->available($this->formObject?->synonymFor !== null)
                         ->variables([
@@ -107,25 +141,11 @@ protected function createForm()
     }
 
     #[\Override]
-    protected function finalizeForm()
+    protected function finalizeForm(): void
     {
         parent::finalizeForm();
 
         $this->form->getDataHandler()
-            ->addProcessor(
-                new CustomFormDataProcessor(
-                    'tagNameProcessor',
-                    static function (IFormDocument $document, array $parameters) {
-                        $parameters['data']['name'] = \str_replace(
-                            ',',
-                            '',
-                            StringUtil::trim($parameters['data']['name'])
-                        );
-
-                        return $parameters;
-                    }
-                )
-            )
             ->addProcessor(
                 new CustomFormDataProcessor(
                     'synonymsProcessor',
diff --git a/wcfsetup/install/files/lib/acp/form/TagEditForm.class.php b/wcfsetup/install/files/lib/acp/form/TagEditForm.class.php
index 2b53db1058..b79b9828fd 100644
--- a/wcfsetup/install/files/lib/acp/form/TagEditForm.class.php
+++ b/wcfsetup/install/files/lib/acp/form/TagEditForm.class.php
@@ -34,7 +34,7 @@ class TagEditForm extends TagAddForm
     /**
      * @inheritDoc
      */
-    public $formAction = 'edit';
+    public string $formAction = 'edit';
 
     #[\Override]
     public function readParameters()
diff --git a/wcfsetup/install/files/lib/command/tag/CreateTag.class.php b/wcfsetup/install/files/lib/command/tag/CreateTag.class.php
new file mode 100644
index 0000000000..d1610dd668
--- /dev/null
+++ b/wcfsetup/install/files/lib/command/tag/CreateTag.class.php
@@ -0,0 +1,32 @@
+<?php
+
+namespace wcf\command\tag;
+
+use wcf\data\tag\Tag;
+use wcf\data\tag\TagBuilder;
+use wcf\event\tag\TagCreated;
+use wcf\system\event\EventHandler;
+
+/**
+ * Creates a new tag.
+ *
+ * @author      Marcel Werk
+ * @copyright   2001-2026 WoltLab GmbH
+ * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @since       6.3
+ */
+final class CreateTag
+{
+    public function __construct(
+        private readonly TagBuilder $builder,
+    ) {}
+
+    public function __invoke(): Tag
+    {
+        $tag = $this->builder->save();
+
+        EventHandler::getInstance()->fire(new TagCreated($tag));
+
+        return $tag;
+    }
+}
diff --git a/wcfsetup/install/files/lib/command/tag/UpdateTag.class.php b/wcfsetup/install/files/lib/command/tag/UpdateTag.class.php
new file mode 100644
index 0000000000..d98cd76709
--- /dev/null
+++ b/wcfsetup/install/files/lib/command/tag/UpdateTag.class.php
@@ -0,0 +1,32 @@
+<?php
+
+namespace wcf\command\tag;
+
+use wcf\data\tag\Tag;
+use wcf\data\tag\TagBuilder;
+use wcf\event\tag\TagUpdated;
+use wcf\system\event\EventHandler;
+
+/**
+ * Updates a tag.
+ *
+ * @author      Marcel Werk
+ * @copyright   2001-2026 WoltLab GmbH
+ * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @since       6.3
+ */
+final class UpdateTag
+{
+    public function __construct(
+        private readonly TagBuilder $builder,
+    ) {}
+
+    public function __invoke(): Tag
+    {
+        $tag = $this->builder->save();
+
+        EventHandler::getInstance()->fire(new TagUpdated($tag));
+
+        return $tag;
+    }
+}
diff --git a/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php b/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
index 89ec16810f..603b024cdd 100644
--- a/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
+++ b/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
@@ -94,6 +94,8 @@ private function create(): int|string
             throw new \BadMethodCallException("Missing value for '" . static::getBaseClass()::getDatabaseTableIndexName() . "'");
         }
 
+        $this->afterCreate($id);
+
         return $id;
     }
 
@@ -122,6 +124,8 @@ private function update(): void
                 WHERE   " . static::getBaseClass()::getDatabaseTableIndexName() . " = ?";
         $statement = WCF::getDB()->prepare($sql);
         $statement->execute($statementParameters);
+
+        $this->afterUpdate();
     }
 
     /**
@@ -247,4 +251,22 @@ public function setCustomProperty(string $name, string|int|float|null $value): s
 
         return $this;
     }
+
+    /**
+     * This method is called after the creation of a new object.
+     * It can be overriden to handle additional tasks that are not handled by the default implementation.
+     */
+    protected function afterCreate(int|string $id): void
+    {
+        // does nothing
+    }
+
+    /**
+     * This method is called after an update.
+     * It can be overriden to handle additional tasks that are not handled by the default implementation.
+     */
+    protected function afterUpdate(): void
+    {
+        // does nothing
+    }
 }
diff --git a/wcfsetup/install/files/lib/data/tag/TagBuilder.class.php b/wcfsetup/install/files/lib/data/tag/TagBuilder.class.php
index 882ee6f3de..4646ce7ff1 100644
--- a/wcfsetup/install/files/lib/data/tag/TagBuilder.class.php
+++ b/wcfsetup/install/files/lib/data/tag/TagBuilder.class.php
@@ -3,6 +3,7 @@
 namespace wcf\data\tag;
 
 use wcf\data\DatabaseObjectBuilder;
+use wcf\system\WCF;
 
 /**
  * Builder for creating, updating and deleting tags.
@@ -16,6 +17,11 @@
  */
 final class TagBuilder extends DatabaseObjectBuilder
 {
+    /**
+     * @var ?list<string>
+     */
+    private ?array $synonyms = null;
+
     public function setTagID(int $tagID): static
     {
         $this->properties['tagID'] = $tagID;
@@ -43,4 +49,67 @@ public function setSynonymFor(Tag $tag): static
 
         return $this;
     }
+
+    /**
+     * @param list<string> $synonyms
+     */
+    public function setSynonyms(array $synonyms): static
+    {
+        $this->synonyms = $synonyms;
+
+        return $this;
+    }
+
+    #[\Override]
+    protected function afterCreate(int|string $id): void
+    {
+        if ($this->synonyms !== null && $this->synonyms !== []) {
+            $this->saveSynonyms(new Tag($id), $this->synonyms);
+        }
+    }
+
+    #[\Override]
+    protected function afterUpdate(): void
+    {
+        if ($this->synonyms !== null) {
+            $this->removeSynonyms($this->object);
+
+            if ($this->synonyms !== []) {
+                $this->saveSynonyms($this->object, $this->synonyms);
+            }
+        }
+    }
+
+    private function removeSynonyms(Tag $tag): void
+    {
+        $sql = "UPDATE  wcf1_tag
+                SET     synonymFor = ?
+                WHERE   synonymFor = ?";
+        $statement = WCF::getDB()->prepare($sql);
+        $statement->execute([
+            null,
+            $tag->tagID,
+        ]);
+    }
+
+    /**
+     * @param list<string> $synonyms
+     */
+    private function saveSynonyms(Tag $tag, array $synonyms): void
+    {
+        foreach ($synonyms as $synonym) {
+            $synonymObj = Tag::getTag($synonym, $tag->languageID);
+            if ($synonymObj === null) {
+                TagBuilder::forCreate()
+                    ->setName($synonym)
+                    ->setLanguageID($tag->languageID)
+                    ->setSynonymFor($tag)
+                    ->save();
+            } else {
+                TagBuilder::forUpdate($synonymObj)
+                    ->setSynonymFor($tag)
+                    ->save();
+            }
+        }
+    }
 }
diff --git a/wcfsetup/install/files/lib/event/tag/TagCreated.class.php b/wcfsetup/install/files/lib/event/tag/TagCreated.class.php
new file mode 100644
index 0000000000..cc1760b0c6
--- /dev/null
+++ b/wcfsetup/install/files/lib/event/tag/TagCreated.class.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace wcf\event\tag;
+
+use wcf\data\tag\Tag;
+use wcf\event\IPsr14Event;
+
+/**
+ * Indicates that a tag has been created.
+ *
+ * @author      Marcel Werk
+ * @copyright   2001-2026 WoltLab GmbH
+ * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @since       6.3
+ */
+final class TagCreated implements IPsr14Event
+{
+    public function __construct(
+        public readonly Tag $tag
+    ) {}
+}
diff --git a/wcfsetup/install/files/lib/event/tag/TagUpdated.class.php b/wcfsetup/install/files/lib/event/tag/TagUpdated.class.php
new file mode 100644
index 0000000000..bbe312305f
--- /dev/null
+++ b/wcfsetup/install/files/lib/event/tag/TagUpdated.class.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace wcf\event\tag;
+
+use wcf\data\tag\Tag;
+use wcf\event\IPsr14Event;
+
+/**
+ * Indicates that a tag has been updated.
+ *
+ * @author      Marcel Werk
+ * @copyright   2001-2026 WoltLab GmbH
+ * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @since       6.3
+ */
+final class TagUpdated implements IPsr14Event
+{
+    public function __construct(
+        public readonly Tag $tag
+    ) {}
+}
diff --git a/wcfsetup/install/files/lib/form/AbstractDatabaseObjectBuilderForm.class.php b/wcfsetup/install/files/lib/form/AbstractDatabaseObjectBuilderForm.class.php
new file mode 100644
index 0000000000..dc1dee200a
--- /dev/null
+++ b/wcfsetup/install/files/lib/form/AbstractDatabaseObjectBuilderForm.class.php
@@ -0,0 +1,262 @@
+<?php
+
+namespace wcf\form;
+
+use wcf\data\DatabaseObject;
+use wcf\data\DatabaseObjectBuilder;
+use wcf\data\IStorableObject;
+use wcf\system\event\EventHandler;
+use wcf\system\exception\UserInputException;
+use wcf\system\form\builder\DatabaseObjectBuilderFormDocument;
+use wcf\system\form\builder\IFormDocument;
+use wcf\system\request\IRouteController;
+use wcf\system\request\LinkHandler;
+use wcf\system\WCF;
+
+/**
+ * Abstract implementation of a form using the form builder API that persists
+ * its data through a `DatabaseObjectBuilder` and a command instead of a
+ * database object action.
+ *
+ * Deriving classes provide the builder via `getDatabaseObjectBuilder()`. The
+ * form's fields write their save values into the builder by registering a
+ * callback via `IFormField::saveValueCallback()`. Saving is performed by the
+ * command returned by `getCommand()`, which defaults to `SaveDatabaseObject`.
+ *
+ * @author      Marcel Werk
+ * @copyright   2001-2026 WoltLab GmbH
+ * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @since       6.3
+ *
+ * @template TIStorableObject of IStorableObject|null
+ * @template TDatabaseObjectBuilder of DatabaseObjectBuilder
+ */
+abstract class AbstractDatabaseObjectBuilderForm extends AbstractForm
+{
+    public DatabaseObjectBuilderFormDocument $form;
+
+    /**
+     * Action performed by the form by default `create` and `edit` is supported.
+     */
+    public string $formAction = 'create';
+
+    /**
+     * updated object, not relevant for form action `create`
+     * @var ?TIStorableObject
+     */
+    public ?IStorableObject $formObject = null;
+
+    /**
+     * name of the controller for the link to the edit form
+     */
+    public string $objectEditLinkController = '';
+
+    /**
+     * object persisted by the most recent `save()` call
+     */
+    public ?DatabaseObject $object = null;
+
+    /**
+     * Returns the builder used to persist the form data.
+     *
+     * For the `create` action a builder obtained via `forCreate()` is expected,
+     * for the `edit` action a builder obtained via `forUpdate($this->formObject)`.
+     *
+     * @return TDatabaseObjectBuilder
+     */
+    abstract protected function getDatabaseObjectBuilder(): DatabaseObjectBuilder;
+
+    /**
+     * Returns the invokable command that persists the given builder and returns
+     * the resulting database object.
+     *
+     * The default command simply calls `DatabaseObjectBuilder::save()`. Override
+     * this method to wrap saving in a command that performs additional side
+     * effects.
+     *
+     * @param TDatabaseObjectBuilder $builder
+     * @return callable(): DatabaseObject
+     */
+    protected function getCommand(DatabaseObjectBuilder $builder): callable
+    {
+        return static fn() => $builder->save();
+    }
+
+    #[\Override]
+    public function assignVariables()
+    {
+        parent::assignVariables();
+
+        WCF::getTPL()->assign([
+            'action' => $this->formAction === 'create' ? 'add' : 'edit',
+            'form' => $this->form,
+            'formObject' => $this->formObject,
+        ]);
+    }
+
+    /**
+     * Builds the form.
+     */
+    public function buildForm(): void
+    {
+        $classNamePieces = \explode('\\', static::class);
+        $controller = \preg_replace('~Form$~', '', \end($classNamePieces));
+
+        $this->form = DatabaseObjectBuilderFormDocument::create(\lcfirst($controller));
+
+        if ($this->formObject !== null) {
+            $this->form->formMode(IFormDocument::FORM_MODE_UPDATE);
+        }
+
+        $this->createForm();
+
+        EventHandler::getInstance()->fireAction($this, 'createForm');
+
+        $this->form->build();
+
+        $this->finalizeForm();
+
+        EventHandler::getInstance()->fireAction($this, 'buildForm');
+    }
+
+    /**
+     * Creates the form.
+     *
+     * This is the method that is intended to be overwritten by child classes
+     * to add the form containers and fields.
+     */
+    protected function createForm(): void
+    {
+        // does nothing
+    }
+
+    /**
+     * Finalizes the form after it has been successfully built.
+     *
+     * This method can be used to add form field dependencies.
+     */
+    protected function finalizeForm(): void
+    {
+        // does nothing
+    }
+
+    #[\Override]
+    public function readData(): void
+    {
+        if ($this->formObject !== null) {
+            $this->setFormObjectData();
+        } elseif ($this->formAction === 'edit') {
+            throw new \UnexpectedValueException("Missing form object to update.");
+        }
+
+        parent::readData();
+
+        $this->setFormAction();
+    }
+
+    #[\Override]
+    public function readFormParameters(): void
+    {
+        parent::readFormParameters();
+
+        $this->form->readValues();
+    }
+
+    #[\Override]
+    public function save(): void
+    {
+        parent::save();
+
+        $builder = $this->getDatabaseObjectBuilder();
+        $this->form->applyValuesToBuilder($builder);
+
+        foreach ($this->additionalFields as $name => $value) {
+            $builder->setCustomProperty($name, $value);
+        }
+
+        $this->object = ($this->getCommand($builder))();
+
+        $this->saved();
+
+        WCF::getTPL()->assign('success', true);
+
+        if ($this->formAction === 'create' && $this->objectEditLinkController) {
+            WCF::getTPL()->assign(
+                'objectEditLink',
+                LinkHandler::getInstance()->getControllerLink($this->objectEditLinkController, [
+                    'id' => $this->object->getObjectID(),
+                ])
+            );
+        }
+    }
+
+    #[\Override]
+    public function saved(): void
+    {
+        parent::saved();
+
+        // re-build form after having created a new object
+        if ($this->formAction === 'create') {
+            $this->form->cleanup();
+
+            $this->buildForm();
+        }
+
+        $this->form->showSuccessMessage(true);
+    }
+
+    /**
+     * Sets the action of the form.
+     */
+    protected function setFormAction(): void
+    {
+        $parameters = [];
+        if ($this->formObject !== null) {
+            if ($this->formObject instanceof IRouteController) {
+                $parameters['object'] = $this->formObject;
+            } else {
+                $object = $this->formObject;
+                // @phpstan-ignore function.alreadyNarrowedType, instanceof.alwaysTrue
+                \assert($object instanceof IStorableObject);
+
+                $parameters['id'] = $object->{$object::getDatabaseTableIndexName()};
+            }
+        }
+
+        $this->form->action(LinkHandler::getInstance()->getControllerLink(static::class, $parameters));
+    }
+
+    /**
+     * Sets the form data based on the current form object.
+     */
+    protected function setFormObjectData(): void
+    {
+        $this->form->updatedObject($this->formObject, empty($_POST));
+    }
+
+    #[\Override]
+    public function checkPermissions(): void
+    {
+        parent::checkPermissions();
+
+        $this->buildForm();
+    }
+
+    #[\Override]
+    public function validate(): void
+    {
+        parent::validate();
+
+        $this->form->validate();
+
+        if ($this->form->hasValidationErrors()) {
+            throw new UserInputException($this->form->getPrefixedId());
+        }
+    }
+
+    #[\Override]
+    protected function validateSecurityToken(): void
+    {
+        // does nothing, is handled by `IFormDocument` object
+    }
+}
diff --git a/wcfsetup/install/files/lib/system/form/builder/DatabaseObjectBuilderFormDocument.class.php b/wcfsetup/install/files/lib/system/form/builder/DatabaseObjectBuilderFormDocument.class.php
new file mode 100644
index 0000000000..58625d7472
--- /dev/null
+++ b/wcfsetup/install/files/lib/system/form/builder/DatabaseObjectBuilderFormDocument.class.php
@@ -0,0 +1,67 @@
+<?php
+
+namespace wcf\system\form\builder;
+
+use wcf\data\DatabaseObjectBuilder;
+use wcf\system\form\builder\field\IFormField;
+
+/**
+ * Represents a form document whose field values are written into a
+ * `DatabaseObjectBuilder` instead of being collected into a parameters array
+ * for a database object action.
+ *
+ * Fields contribute their value by registering a callback via
+ * `IFormField::saveValueCallback()`:
+ *
+ *     $field->saveValueCallback(
+ *         static fn(DatabaseObjectBuilder $builder, IFormField $formField) => $builder->setName($formField->getSaveValue())
+ *     )
+ *
+ * @author      Marcel Werk
+ * @copyright   2001-2026 WoltLab GmbH
+ * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @since       6.3
+ */
+class DatabaseObjectBuilderFormDocument extends FormDocument
+{
+    /**
+     * Applies the save values of all available form fields that have registered
+     * a save value callback to the given builder and returns the builder.
+     *
+     * @param DatabaseObjectBuilder<*> $builder
+     * @throws \BadMethodCallException if the method is called before `readValues()` is called
+     */
+    public function applyValuesToBuilder(DatabaseObjectBuilder $builder): void
+    {
+        if (!$this->didReadValues()) {
+            throw new \BadMethodCallException("Applying values to a builder is only possible after calling 'readValues()'.");
+        }
+
+        $this->applyNodeValues($this, $builder);
+    }
+
+    /**
+     * Recursively applies the save value callbacks of the given node and its
+     * children to the builder, mirroring the availability and dependency
+     * handling of `DefaultFormDataProcessor`.
+     *
+     * @param DatabaseObjectBuilder<*> $builder
+     */
+    protected function applyNodeValues(IFormNode $node, DatabaseObjectBuilder $builder): void
+    {
+        if (!$node->isAvailable() || !$node->checkDependencies()) {
+            return;
+        }
+
+        if ($node instanceof IFormParentNode) {
+            foreach ($node as $childNode) {
+                $this->applyNodeValues($childNode, $builder);
+            }
+        } elseif ($node instanceof IFormField) {
+            $callback = $node->getSaveValueCallback();
+            if ($callback !== null) {
+                $callback($builder, $node);
+            }
+        }
+    }
+}
diff --git a/wcfsetup/install/files/lib/system/form/builder/field/AbstractFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/AbstractFormField.class.php
index badb8b8a35..a517052d6c 100644
--- a/wcfsetup/install/files/lib/system/form/builder/field/AbstractFormField.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/AbstractFormField.class.php
@@ -71,6 +71,13 @@ abstract class AbstractFormField implements IFormField
      */
     protected $value;
 
+    /**
+     * callback transferring this field's save value into a `DatabaseObjectBuilder`
+     * @var ?\Closure(\wcf\data\DatabaseObjectBuilder<*>, IFormField): mixed
+     * @since 6.3
+     */
+    protected ?\Closure $saveValueCallback = null;
+
     #[\Override]
     public function addValidationError(IFormFieldValidationError $error)
     {
@@ -165,6 +172,20 @@ public function getValue()
         return $this->value;
     }
 
+    #[\Override]
+    public function saveValueCallback(\Closure $callback): static
+    {
+        $this->saveValueCallback = $callback;
+
+        return $this;
+    }
+
+    #[\Override]
+    public function getSaveValueCallback(): ?\Closure
+    {
+        return $this->saveValueCallback;
+    }
+
     #[\Override]
     public function hasValidator(string $validatorId)
     {
diff --git a/wcfsetup/install/files/lib/system/form/builder/field/AbstractFormFieldDecorator.class.php b/wcfsetup/install/files/lib/system/form/builder/field/AbstractFormFieldDecorator.class.php
index 4d00dbea84..0c649ddbe9 100644
--- a/wcfsetup/install/files/lib/system/form/builder/field/AbstractFormFieldDecorator.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/AbstractFormFieldDecorator.class.php
@@ -87,6 +87,20 @@ public function getValue()
         return $this->field->getValue();
     }
 
+    #[\Override]
+    public function saveValueCallback(\Closure $callback): static
+    {
+        $this->field->saveValueCallback($callback);
+
+        return $this;
+    }
+
+    #[\Override]
+    public function getSaveValueCallback(): ?\Closure
+    {
+        return $this->field->getSaveValueCallback();
+    }
+
     #[\Override]
     public function hasValidator(string $validatorId)
     {
diff --git a/wcfsetup/install/files/lib/system/form/builder/field/IFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/IFormField.class.php
index 89330390b2..4197450242 100644
--- a/wcfsetup/install/files/lib/system/form/builder/field/IFormField.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/IFormField.class.php
@@ -2,6 +2,7 @@
 
 namespace wcf\system\form\builder\field;
 
+use wcf\data\DatabaseObjectBuilder;
 use wcf\data\IStorableObject;
 use wcf\system\form\builder\field\validation\IFormFieldValidationError;
 use wcf\system\form\builder\field\validation\IFormFieldValidator;
@@ -94,6 +95,37 @@ public function getValidators();
      */
     public function getValue();
 
+    /**
+     * Sets a callback that transfers this field's save value into a
+     * `DatabaseObjectBuilder` instance and returns this field.
+     *
+     * The callback is invoked by `DatabaseObjectBuilderFormDocument` when the
+     * builder is populated from the form's fields, for example:
+     *
+     *     $field->saveValueCallback(
+     *         static fn(DatabaseObjectBuilder $builder, IFormField $formField) => $builder->setName($formField->getSaveValue())
+     *     )
+     *
+     * The builder type is a template parameter so that the callback may narrow
+     * it to a concrete `DatabaseObjectBuilder` implementation (e.g. `TagBuilder`)
+     * without triggering a contravariance error.
+     *
+     * @template TBuilder of DatabaseObjectBuilder
+     * @param \Closure(TBuilder, IFormField): mixed $callback
+     * @return static this field
+     * @since 6.3
+     */
+    public function saveValueCallback(\Closure $callback): static;
+
+    /**
+     * Returns the callback set via `saveValueCallback()` or `null` if no such
+     * callback has been set.
+     *
+     * @return ?\Closure(DatabaseObjectBuilder<*>, IFormField): mixed
+     * @since 6.3
+     */
+    public function getSaveValueCallback(): ?\Closure;
+
     /**
      * Returns `true` if this field has a validator with the given id and
      * returns `false` otherwise.

From 66329357b5725bcd14a2add6b400116848aaabe9 Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Thu, 25 Jun 2026 23:01:17 +0200
Subject: [PATCH 03/17] Simplify checks in `AbstractDatabaseObjectBuilderForm`

---
 .../lib/form/AbstractDatabaseObjectBuilderForm.class.php     | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/wcfsetup/install/files/lib/form/AbstractDatabaseObjectBuilderForm.class.php b/wcfsetup/install/files/lib/form/AbstractDatabaseObjectBuilderForm.class.php
index dc1dee200a..c83d619f1b 100644
--- a/wcfsetup/install/files/lib/form/AbstractDatabaseObjectBuilderForm.class.php
+++ b/wcfsetup/install/files/lib/form/AbstractDatabaseObjectBuilderForm.class.php
@@ -216,9 +216,6 @@ protected function setFormAction(): void
                 $parameters['object'] = $this->formObject;
             } else {
                 $object = $this->formObject;
-                // @phpstan-ignore function.alreadyNarrowedType, instanceof.alwaysTrue
-                \assert($object instanceof IStorableObject);
-
                 $parameters['id'] = $object->{$object::getDatabaseTableIndexName()};
             }
         }
@@ -231,7 +228,7 @@ protected function setFormAction(): void
      */
     protected function setFormObjectData(): void
     {
-        $this->form->updatedObject($this->formObject, empty($_POST));
+        $this->form->updatedObject($this->formObject, $_POST === []);
     }
 
     #[\Override]

From b90f591680eee894ccbfc7c5f6f8e7cb15ff32f0 Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Fri, 26 Jun 2026 13:46:03 +0200
Subject: [PATCH 04/17] Add `beforeDeleteAll()` hook and seal
 `DatabaseObjectBuilder` API

---
 .../lib/data/DatabaseObjectBuilder.class.php  | 31 +++++++++++++------
 1 file changed, 22 insertions(+), 9 deletions(-)

diff --git a/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php b/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
index 603b024cdd..2da48d4082 100644
--- a/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
+++ b/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
@@ -42,7 +42,7 @@ private function __construct(protected readonly ?DatabaseObject $object = null)
      *
      * @return TDatabaseObject
      */
-    public function save(): DatabaseObject
+    final public function save(): DatabaseObject
     {
         return new (static::getBaseClass())($this->fastSave());
     }
@@ -51,7 +51,7 @@ public function save(): DatabaseObject
      * Persists the pending changes and returns the object's identifier without
      * instantiating the full database object.
      */
-    public function fastSave(): int|string
+    final public function fastSave(): int|string
     {
         if ($this->object !== null) {
             $this->update();
@@ -133,7 +133,7 @@ private function update(): void
      *
      * @return ?TDatabaseObject
      */
-    public function createOrIgnore(): ?DatabaseObject
+    final public function createOrIgnore(): ?DatabaseObject
     {
         if ($this->object !== null) {
             throw new \BadMethodCallException("createOrIgnore() can only be used with forCreate().");
@@ -156,7 +156,7 @@ public function createOrIgnore(): ?DatabaseObject
      *
      * @param TDatabaseObject $object
      */
-    public static function delete(DatabaseObject $object): void
+    final public static function delete(DatabaseObject $object): void
     {
         static::deleteAll([$object->getObjectID()]);
     }
@@ -167,12 +167,14 @@ public static function delete(DatabaseObject $object): void
      *
      * @param (string|int)[] $objectIDs
      */
-    public static function deleteAll(array $objectIDs = []): void
+    final public static function deleteAll(array $objectIDs = []): void
     {
         if ($objectIDs === []) {
             return;
         }
 
+        static::beforeDeleteAll($objectIDs);
+
         $itemsPerLoop = 1000;
         $loopCount = \ceil(\count($objectIDs) / $itemsPerLoop);
 
@@ -202,7 +204,7 @@ public static function deleteAll(array $objectIDs = []): void
     /**
      * Returns a builder instance for inserting a new row.
      */
-    public static function forCreate(): static
+    final public static function forCreate(): static
     {
         return new (static::class)();
     }
@@ -212,7 +214,7 @@ public static function forCreate(): static
      *
      * @param TDatabaseObject $object
      */
-    public static function forUpdate(DatabaseObject $object): static
+    final public static function forUpdate(DatabaseObject $object): static
     {
         return new static($object);
     }
@@ -223,7 +225,7 @@ public static function forUpdate(DatabaseObject $object): static
      *
      * @return class-string<DatabaseObject>
      */
-    public static function getBaseClass(): string
+    final public static function getBaseClass(): string
     {
         if (!\str_ends_with(static::class, 'Builder')) {
             throw new \LogicException("Builder class '" . static::class . "' must end with the 'Builder' suffix.");
@@ -245,7 +247,7 @@ public static function getBaseClass(): string
      * Sets a custom property value that is written alongside the regular
      * properties when the object is persisted.
      */
-    public function setCustomProperty(string $name, string|int|float|null $value): static
+    final public function setCustomProperty(string $name, string|int|float|null $value): static
     {
         $this->customProperties[$name] = $value;
 
@@ -269,4 +271,15 @@ protected function afterUpdate(): void
     {
         // does nothing
     }
+
+    /**
+     * This method is called before the deletion of objects.
+     * It can be overriden to handle additional tasks that are not handled by the default implementation.
+     *
+     * @param (string|int)[] $objectIDs
+     */
+    protected static function beforeDeleteAll(array $objectIDs): void
+    {
+        // does nothing
+    }
 }

From 51cfd925be37a98aea956145795bfa0780669fc2 Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Fri, 26 Jun 2026 13:48:05 +0200
Subject: [PATCH 05/17] Use fully qualified `\array_merge()` calls

---
 .../install/files/lib/data/DatabaseObjectBuilder.class.php    | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php b/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
index 2da48d4082..842e240460 100644
--- a/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
+++ b/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
@@ -69,7 +69,7 @@ private function create(): int|string
     {
         $keys = $values = '';
         $statementParameters = [];
-        foreach (array_merge($this->properties, $this->customProperties) as $key => $value) {
+        foreach (\array_merge($this->properties, $this->customProperties) as $key => $value) {
             if ($keys !== '') {
                 $keys .= ',';
                 $values .= ',';
@@ -110,7 +110,7 @@ private function update(): void
 
         $updateSQL = '';
         $statementParameters = [];
-        foreach (array_merge($this->properties, $this->customProperties) as $key => $value) {
+        foreach (\array_merge($this->properties, $this->customProperties) as $key => $value) {
             if ($updateSQL !== '') {
                 $updateSQL .= ', ';
             }

From a73221e2f82c6ce61f68a77f7f10d8cced1ad4ed Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Fri, 26 Jun 2026 14:10:41 +0200
Subject: [PATCH 06/17] Add `setID()` for explicit ID assignment on create

---
 .../lib/data/DatabaseObjectBuilder.class.php  | 30 +++++++++++++++----
 .../files/lib/data/tag/TagBuilder.class.php   |  7 -----
 2 files changed, 25 insertions(+), 12 deletions(-)

diff --git a/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php b/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
index 842e240460..ed8375c7a2 100644
--- a/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
+++ b/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
@@ -86,10 +86,10 @@ private function create(): int|string
         $statement = WCF::getDB()->prepare($sql);
         $statement->execute($statementParameters);
 
-        if (static::getBaseClass()::getDatabaseTableIndexIsIdentity()) {
-            $id = WCF::getDB()->getInsertID(static::getBaseClass()::getDatabaseTableName(), static::getBaseClass()::getDatabaseTableIndexName());
-        } elseif (isset($this->properties[static::getBaseClass()::getDatabaseTableIndexName()])) {
+        if (isset($this->properties[static::getBaseClass()::getDatabaseTableIndexName()])) {
             $id = $this->properties[static::getBaseClass()::getDatabaseTableIndexName()];
+        } elseif (static::getBaseClass()::getDatabaseTableIndexIsIdentity()) {
+            $id = WCF::getDB()->getInsertID(static::getBaseClass()::getDatabaseTableName(), static::getBaseClass()::getDatabaseTableIndexName());
         } else {
             throw new \BadMethodCallException("Missing value for '" . static::getBaseClass()::getDatabaseTableIndexName() . "'");
         }
@@ -165,7 +165,7 @@ final public static function delete(DatabaseObject $object): void
      * Deletes the rows identified by the given primary keys in batches inside
      * a single transaction.
      *
-     * @param (string|int)[] $objectIDs
+     * @param (int|string)[] $objectIDs
      */
     final public static function deleteAll(array $objectIDs = []): void
     {
@@ -276,10 +276,30 @@ protected function afterUpdate(): void
      * This method is called before the deletion of objects.
      * It can be overriden to handle additional tasks that are not handled by the default implementation.
      *
-     * @param (string|int)[] $objectIDs
+     * @param (int|string)[] $objectIDs
      */
     protected static function beforeDeleteAll(array $objectIDs): void
     {
         // does nothing
     }
+
+    /**
+     * Sets the ID of the object that is being created.
+     *
+     * This method should only be used in cases where the ID needs to be set
+     * explicitly, for example when importing existing records from another
+     * installation, where the ID should be preserved if possible.
+     *
+     * @throws \BadMethodCallException if an existing object is being updated
+     */
+    final public function setID(int|string $id): static
+    {
+        if ($this->object !== null) {
+            throw new \BadMethodCallException('The ID cannot be set when updating an existing object.');
+        }
+
+        $this->properties[static::getBaseClass()::getDatabaseTableIndexName()] = $id;
+
+        return $this;
+    }
 }
diff --git a/wcfsetup/install/files/lib/data/tag/TagBuilder.class.php b/wcfsetup/install/files/lib/data/tag/TagBuilder.class.php
index 4646ce7ff1..5dc775293a 100644
--- a/wcfsetup/install/files/lib/data/tag/TagBuilder.class.php
+++ b/wcfsetup/install/files/lib/data/tag/TagBuilder.class.php
@@ -22,13 +22,6 @@ final class TagBuilder extends DatabaseObjectBuilder
      */
     private ?array $synonyms = null;
 
-    public function setTagID(int $tagID): static
-    {
-        $this->properties['tagID'] = $tagID;
-
-        return $this;
-    }
-
     public function setLanguageID(int $languageID): static
     {
         $this->properties['languageID'] = $languageID;

From eb6cf2be8337bc18e45ec463a7d38beed210f3a3 Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Sun, 28 Jun 2026 16:21:50 +0200
Subject: [PATCH 07/17] Add `loadValueCallback()` to `IFormField` for custom
 value loading

Introduce a counterpart to `saveValueCallback()` that loads a field's value from an `IStorableObject` when an edit form is populated. When set, the callback takes precedence over the default property-based loading in `updatedObject()`, allowing values that must be derived from a related object or an additional query.
---
 .../files/lib/acp/form/TagAddForm.class.php   | 53 ++++++-------------
 .../builder/field/AbstractFormField.class.php | 29 +++++++++-
 .../AbstractFormFieldDecorator.class.php      | 14 +++++
 .../form/builder/field/IFormField.class.php   | 41 ++++++++++++++
 .../builder/field/tag/TagFormField.class.php  |  4 +-
 5 files changed, 102 insertions(+), 39 deletions(-)

diff --git a/wcfsetup/install/files/lib/acp/form/TagAddForm.class.php b/wcfsetup/install/files/lib/acp/form/TagAddForm.class.php
index 09d249ee92..05be1bb548 100644
--- a/wcfsetup/install/files/lib/acp/form/TagAddForm.class.php
+++ b/wcfsetup/install/files/lib/acp/form/TagAddForm.class.php
@@ -5,20 +5,17 @@
 use wcf\command\tag\CreateTag;
 use wcf\command\tag\UpdateTag;
 use wcf\data\DatabaseObjectBuilder;
-use wcf\data\IStorableObject;
 use wcf\data\tag\Tag;
 use wcf\data\tag\TagBuilder;
 use wcf\data\tag\TagList;
 use wcf\form\AbstractDatabaseObjectBuilderForm;
 use wcf\system\form\builder\container\FormContainer;
-use wcf\system\form\builder\data\processor\CustomFormDataProcessor;
 use wcf\system\form\builder\field\IFormField;
 use wcf\system\form\builder\field\SingleSelectionFormField;
 use wcf\system\form\builder\field\tag\TagFormField;
 use wcf\system\form\builder\field\TextFormField;
 use wcf\system\form\builder\field\validation\FormFieldValidationError;
 use wcf\system\form\builder\field\validation\FormFieldValidator;
-use wcf\system\form\builder\IFormDocument;
 use wcf\system\form\builder\TemplateFormNode;
 use wcf\system\language\LanguageFactory;
 use wcf\system\WCF;
@@ -27,8 +24,8 @@
 /**
  * Shows the tag add form.
  *
- * @author      Olaf Braun, Tim Duesterhus
- * @copyright   2001-2024 WoltLab GmbH
+ * @author      Olaf Braun, Tim Duesterhus, Marcel Werk
+ * @copyright   2001-2026 WoltLab GmbH
  * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
  *
  * @extends AbstractDatabaseObjectBuilderForm<Tag, TagBuilder>
@@ -78,8 +75,6 @@ protected function getCommand(DatabaseObjectBuilder $builder): callable
     #[\Override]
     protected function createForm(): void
     {
-        parent::createForm();
-
         $contentLanguages = LanguageFactory::getInstance()->getContentLanguages();
 
         $this->form->appendChildren([
@@ -94,6 +89,9 @@ protected function createForm(): void
                                 \str_replace(',', '', StringUtil::trim($field->getSaveValue()))
                             )
                         )
+                        ->loadValueCallback(static function (Tag $object, IFormField $field) {
+                            $field->value($object->name);
+                        })
                         ->addValidator(
                             new FormFieldValidator('duplicateTagValidator', function (TextFormField $field) {
                                 $languageIDFormField = $field->getDocument()->getFormField('languageID');
@@ -121,7 +119,9 @@ protected function createForm(): void
                             static fn(TagBuilder $builder, IFormField $field) => $builder->setLanguageID(
                                 (int)$field->getSaveValue()
                             )
-                        ),
+                        )->loadValueCallback(static function (Tag $object, IFormField $field) {
+                            $field->value($object->languageID);
+                        }),
                     TagFormField::create('synonyms')
                         ->available($this->formObject?->synonymFor === null)
                         ->label('wcf.acp.tag.synonyms')
@@ -129,7 +129,15 @@ protected function createForm(): void
                             static fn(TagBuilder $builder, IFormField $field) => $builder->setSynonyms(
                                 $field->getSaveValue() ?? []
                             )
-                        ),
+                        )->loadValueCallback(static function (Tag $object, IFormField $field) {
+                            $synonymList = new TagList();
+                            $synonymList->getConditionBuilder()->add('synonymFor = ?', [$object->getObjectID()]);
+                            $synonymList->readObjects();
+                            $field->value(\array_map(
+                                static fn($synonym) => $synonym->name,
+                                $synonymList->getObjects()
+                            ));
+                        }),
                     TemplateFormNode::create('tagSynonymFor')
                         ->available($this->formObject?->synonymFor !== null)
                         ->variables([
@@ -139,31 +147,4 @@ protected function createForm(): void
                 ])
         ]);
     }
-
-    #[\Override]
-    protected function finalizeForm(): void
-    {
-        parent::finalizeForm();
-
-        $this->form->getDataHandler()
-            ->addProcessor(
-                new CustomFormDataProcessor(
-                    'synonymsProcessor',
-                    null,
-                    static function (IFormDocument $document, array $data, IStorableObject $tag) {
-                        \assert($tag instanceof Tag);
-
-                        $synonymList = new TagList();
-                        $synonymList->getConditionBuilder()->add('synonymFor = ?', [$tag->tagID]);
-                        $synonymList->readObjects();
-                        $data['synonyms'] = [];
-                        foreach ($synonymList as $synonym) {
-                            $data['synonyms'][] = $synonym->name;
-                        }
-
-                        return $data;
-                    }
-                )
-            );
-    }
 }
diff --git a/wcfsetup/install/files/lib/system/form/builder/field/AbstractFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/AbstractFormField.class.php
index a517052d6c..73d60f44ba 100644
--- a/wcfsetup/install/files/lib/system/form/builder/field/AbstractFormField.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/AbstractFormField.class.php
@@ -78,6 +78,13 @@ abstract class AbstractFormField implements IFormField
      */
     protected ?\Closure $saveValueCallback = null;
 
+    /**
+     * callback loading this field's value from an `IStorableObject`
+     * @var ?\Closure(\wcf\data\IStorableObject, IFormField): void
+     * @since 6.3
+     */
+    protected ?\Closure $loadValueCallback = null;
+
     #[\Override]
     public function addValidationError(IFormFieldValidationError $error)
     {
@@ -186,6 +193,20 @@ public function getSaveValueCallback(): ?\Closure
         return $this->saveValueCallback;
     }
 
+    #[\Override]
+    public function loadValueCallback(\Closure $callback): static
+    {
+        $this->loadValueCallback = $callback;
+
+        return $this;
+    }
+
+    #[\Override]
+    public function getLoadValueCallback(): ?\Closure
+    {
+        return $this->loadValueCallback;
+    }
+
     #[\Override]
     public function hasValidator(string $validatorId)
     {
@@ -213,8 +234,12 @@ public function updatedObject(array $data, IStorableObject $object, bool $loadVa
             $loadValues = true;
         }
 
-        if ($loadValues && isset($data[$this->getObjectProperty()])) {
-            $this->value($data[$this->getObjectProperty()]);
+        if ($loadValues) {
+            if ($this->loadValueCallback !== null) {
+                ($this->loadValueCallback)($object, $this);
+            } elseif (isset($data[$this->getObjectProperty()])) {
+                $this->value($data[$this->getObjectProperty()]);
+            }
         }
 
         return $this;
diff --git a/wcfsetup/install/files/lib/system/form/builder/field/AbstractFormFieldDecorator.class.php b/wcfsetup/install/files/lib/system/form/builder/field/AbstractFormFieldDecorator.class.php
index 0c649ddbe9..5ed8d4b772 100644
--- a/wcfsetup/install/files/lib/system/form/builder/field/AbstractFormFieldDecorator.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/AbstractFormFieldDecorator.class.php
@@ -101,6 +101,20 @@ public function getSaveValueCallback(): ?\Closure
         return $this->field->getSaveValueCallback();
     }
 
+    #[\Override]
+    public function loadValueCallback(\Closure $callback): static
+    {
+        $this->field->loadValueCallback($callback);
+
+        return $this;
+    }
+
+    #[\Override]
+    public function getLoadValueCallback(): ?\Closure
+    {
+        return $this->field->getLoadValueCallback();
+    }
+
     #[\Override]
     public function hasValidator(string $validatorId)
     {
diff --git a/wcfsetup/install/files/lib/system/form/builder/field/IFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/IFormField.class.php
index 4197450242..c15cf1bc56 100644
--- a/wcfsetup/install/files/lib/system/form/builder/field/IFormField.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/IFormField.class.php
@@ -126,6 +126,47 @@ public function saveValueCallback(\Closure $callback): static;
      */
     public function getSaveValueCallback(): ?\Closure;
 
+    /**
+     * Sets a callback that loads this field's value from an `IStorableObject`
+     * and returns this field.
+     *
+     * This is the counterpart to `saveValueCallback()`: while the save callback
+     * writes the field's value into a builder, this callback reads the value
+     * back out of an existing object when an edit form is populated. It is
+     * invoked by `updatedObject()` and is expected to assign the value via
+     * `$field->value()`, for example:
+     *
+     *     $field->loadValueCallback(
+     *         static function (Tag $object, IFormField $formField) {
+     *             $formField->value($object->name);
+     *         }
+     *     )
+     *
+     * When a callback is set it takes precedence over the default behaviour of
+     * loading the value from the object property named after this field. Use it
+     * when the value cannot be read from a single property, e.g. when it must be
+     * derived from a related object or an additional query.
+     *
+     * The object type is a template parameter so that the callback may narrow it
+     * to a concrete `IStorableObject` implementation (e.g. `Tag`) without
+     * triggering a contravariance error.
+     *
+     * @template TObject of IStorableObject
+     * @param \Closure(TObject, IFormField): void $callback
+     * @return static this field
+     * @since 6.3
+     */
+    public function loadValueCallback(\Closure $callback): static;
+
+    /**
+     * Returns the callback set via `loadValueCallback()` or `null` if no such
+     * callback has been set.
+     *
+     * @return ?\Closure(IStorableObject, IFormField): void
+     * @since 6.3
+     */
+    public function getLoadValueCallback(): ?\Closure;
+
     /**
      * Returns `true` if this field has a validator with the given id and
      * returns `false` otherwise.
diff --git a/wcfsetup/install/files/lib/system/form/builder/field/tag/TagFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/tag/TagFormField.class.php
index 295fca4207..bd6c1fe61a 100644
--- a/wcfsetup/install/files/lib/system/form/builder/field/tag/TagFormField.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/tag/TagFormField.class.php
@@ -66,7 +66,9 @@ public function hasSaveValue()
     public function updatedObject(array $data, IStorableObject $object, bool $loadValues = true)
     {
         if ($loadValues) {
-            if (isset($data[$this->getObjectProperty()])) {
+            if ($this->loadValueCallback !== null) {
+                ($this->loadValueCallback)($object, $this);
+            } elseif (isset($data[$this->getObjectProperty()])) {
                 $this->value($data[$this->getObjectProperty()]);
             } else {
                 $objectID = $object->{$object::getDatabaseTableIndexName()};

From 7f1c07a4dcbb81709030b40ea52d0453de1b05c7 Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Sun, 28 Jun 2026 20:02:54 +0200
Subject: [PATCH 08/17] Return void from save value callbacks

---
 .../files/lib/acp/form/TagAddForm.class.php   | 24 +++++++++----------
 .../builder/field/AbstractFormField.class.php |  2 +-
 .../form/builder/field/IFormField.class.php   |  4 ++--
 3 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/wcfsetup/install/files/lib/acp/form/TagAddForm.class.php b/wcfsetup/install/files/lib/acp/form/TagAddForm.class.php
index 05be1bb548..6760932a7e 100644
--- a/wcfsetup/install/files/lib/acp/form/TagAddForm.class.php
+++ b/wcfsetup/install/files/lib/acp/form/TagAddForm.class.php
@@ -84,11 +84,11 @@ protected function createForm(): void
                         ->label('wcf.global.name')
                         ->required()
                         ->maximumLength(\TAGGING_MAX_TAG_LENGTH)
-                        ->saveValueCallback(
-                            static fn(TagBuilder $builder, IFormField $field) => $builder->setName(
+                        ->saveValueCallback(static function (TagBuilder $builder, IFormField $field) {
+                            $builder->setName(
                                 \str_replace(',', '', StringUtil::trim($field->getSaveValue()))
-                            )
-                        )
+                            );
+                        })
                         ->loadValueCallback(static function (Tag $object, IFormField $field) {
                             $field->value($object->name);
                         })
@@ -115,21 +115,21 @@ protected function createForm(): void
                         ->value(isset($contentLanguages[WCF::getLanguage()->languageID]) ? WCF::getLanguage()->languageID : null)
                         ->immutable($this->formAction !== 'create')
                         ->required()
-                        ->saveValueCallback(
-                            static fn(TagBuilder $builder, IFormField $field) => $builder->setLanguageID(
+                        ->saveValueCallback(static function (TagBuilder $builder, IFormField $field) {
+                            $builder->setLanguageID(
                                 (int)$field->getSaveValue()
-                            )
-                        )->loadValueCallback(static function (Tag $object, IFormField $field) {
+                            );
+                        })->loadValueCallback(static function (Tag $object, IFormField $field) {
                             $field->value($object->languageID);
                         }),
                     TagFormField::create('synonyms')
                         ->available($this->formObject?->synonymFor === null)
                         ->label('wcf.acp.tag.synonyms')
-                        ->saveValueCallback(
-                            static fn(TagBuilder $builder, IFormField $field) => $builder->setSynonyms(
+                        ->saveValueCallback(static function (TagBuilder $builder, IFormField $field) {
+                            $builder->setSynonyms(
                                 $field->getSaveValue() ?? []
-                            )
-                        )->loadValueCallback(static function (Tag $object, IFormField $field) {
+                            );
+                        })->loadValueCallback(static function (Tag $object, IFormField $field) {
                             $synonymList = new TagList();
                             $synonymList->getConditionBuilder()->add('synonymFor = ?', [$object->getObjectID()]);
                             $synonymList->readObjects();
diff --git a/wcfsetup/install/files/lib/system/form/builder/field/AbstractFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/AbstractFormField.class.php
index 73d60f44ba..b0e3860d44 100644
--- a/wcfsetup/install/files/lib/system/form/builder/field/AbstractFormField.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/AbstractFormField.class.php
@@ -73,7 +73,7 @@ abstract class AbstractFormField implements IFormField
 
     /**
      * callback transferring this field's save value into a `DatabaseObjectBuilder`
-     * @var ?\Closure(\wcf\data\DatabaseObjectBuilder<*>, IFormField): mixed
+     * @var ?\Closure(\wcf\data\DatabaseObjectBuilder<*>, IFormField): void
      * @since 6.3
      */
     protected ?\Closure $saveValueCallback = null;
diff --git a/wcfsetup/install/files/lib/system/form/builder/field/IFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/IFormField.class.php
index c15cf1bc56..b5006af21d 100644
--- a/wcfsetup/install/files/lib/system/form/builder/field/IFormField.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/IFormField.class.php
@@ -111,7 +111,7 @@ public function getValue();
      * without triggering a contravariance error.
      *
      * @template TBuilder of DatabaseObjectBuilder
-     * @param \Closure(TBuilder, IFormField): mixed $callback
+     * @param \Closure(TBuilder, IFormField): void $callback
      * @return static this field
      * @since 6.3
      */
@@ -121,7 +121,7 @@ public function saveValueCallback(\Closure $callback): static;
      * Returns the callback set via `saveValueCallback()` or `null` if no such
      * callback has been set.
      *
-     * @return ?\Closure(DatabaseObjectBuilder<*>, IFormField): mixed
+     * @return ?\Closure(DatabaseObjectBuilder<*>, IFormField): void
      * @since 6.3
      */
     public function getSaveValueCallback(): ?\Closure;

From 2056d4e5678318524e2a64db9a57e2a7bd3905d5 Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Tue, 30 Jun 2026 16:38:57 +0200
Subject: [PATCH 09/17] Add `updateCounters()` to `DatabaseObjectBuilder

Provides a static helper to atomically increment or decrement counter columns for a given object, mirroring the behavior of the legacy `DatabaseObjectEditor::updateCounters()`.
---
 .../lib/data/DatabaseObjectBuilder.class.php  | 32 +++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php b/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
index ed8375c7a2..3850c1d8c1 100644
--- a/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
+++ b/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
@@ -302,4 +302,36 @@ final public function setID(int|string $id): static
 
         return $this;
     }
+
+    /**
+     * Updates counters for the given object.
+     *
+     * @param TDatabaseObject $object
+     * @param array<string, int|float> $counters
+     */
+    final public static function updateCounters(DatabaseObject $object, array $counters): void
+    {
+        if ($counters === []) {
+            throw new \InvalidArgumentException("The list of counters to update must not be empty.");
+        }
+
+        \assert($object instanceof (static::getBaseClass()));
+
+        $updateSQL = '';
+        $statementParameters = [];
+        foreach ($counters as $key => $value) {
+            if ($updateSQL !== '') {
+                $updateSQL .= ', ';
+            }
+            $updateSQL .= $key . ' = ' . $key . ' + ?';
+            $statementParameters[] = $value;
+        }
+        $statementParameters[] = $object->getObjectID();
+
+        $sql = "UPDATE  " . static::getBaseClass()::getDatabaseTableName() . "
+                SET     " . $updateSQL . "
+                WHERE   " . static::getBaseClass()::getDatabaseTableIndexName() . " = ?";
+        $statement = WCF::getDB()->prepare($sql);
+        $statement->execute($statementParameters);
+    }
 }

From 3a8cb2fe41820e110d1829e2915e2b61d781e559 Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Tue, 30 Jun 2026 16:51:21 +0200
Subject: [PATCH 10/17] Add `getHtmlInputProcessor()` to `WysiwygFormField`

---
 .../builder/field/wysiwyg/WysiwygFormField.class.php | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/wcfsetup/install/files/lib/system/form/builder/field/wysiwyg/WysiwygFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/wysiwyg/WysiwygFormField.class.php
index 4be0c94a24..8e82c40dad 100644
--- a/wcfsetup/install/files/lib/system/form/builder/field/wysiwyg/WysiwygFormField.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/wysiwyg/WysiwygFormField.class.php
@@ -393,4 +393,16 @@ public function getValue()
         $upcastProcessor->process(parent::getValue() ?? '', $this->getObjectType()->objectType);
         return $upcastProcessor->getHtml();
     }
+
+    /**
+     * @since 6.3
+     */
+    public function getHtmlInputProcessor(): HtmlInputProcessor
+    {
+        if ($this->htmlInputProcessor === null) {
+            throw new \BadMethodCallException("The html input processor is not available before validate() has been called.");
+        }
+
+        return $this->htmlInputProcessor;
+    }
 }

From 73d38c5c04268293f255ce65d61a504ab0fb7ecf Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Tue, 30 Jun 2026 17:09:16 +0200
Subject: [PATCH 11/17] Add `afterSave()` hook and use `DatabaseObject` for the
 form object

---
 ...bstractDatabaseObjectBuilderForm.class.php | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/wcfsetup/install/files/lib/form/AbstractDatabaseObjectBuilderForm.class.php b/wcfsetup/install/files/lib/form/AbstractDatabaseObjectBuilderForm.class.php
index c83d619f1b..6a2c04568f 100644
--- a/wcfsetup/install/files/lib/form/AbstractDatabaseObjectBuilderForm.class.php
+++ b/wcfsetup/install/files/lib/form/AbstractDatabaseObjectBuilderForm.class.php
@@ -4,7 +4,6 @@
 
 use wcf\data\DatabaseObject;
 use wcf\data\DatabaseObjectBuilder;
-use wcf\data\IStorableObject;
 use wcf\system\event\EventHandler;
 use wcf\system\exception\UserInputException;
 use wcf\system\form\builder\DatabaseObjectBuilderFormDocument;
@@ -28,7 +27,7 @@
  * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
  * @since       6.3
  *
- * @template TIStorableObject of IStorableObject|null
+ * @template TDatabaseObject of DatabaseObject|null
  * @template TDatabaseObjectBuilder of DatabaseObjectBuilder
  */
 abstract class AbstractDatabaseObjectBuilderForm extends AbstractForm
@@ -42,9 +41,9 @@ abstract class AbstractDatabaseObjectBuilderForm extends AbstractForm
 
     /**
      * updated object, not relevant for form action `create`
-     * @var ?TIStorableObject
+     * @var ?TDatabaseObject
      */
-    public ?IStorableObject $formObject = null;
+    public ?DatabaseObject $formObject = null;
 
     /**
      * name of the controller for the link to the edit form
@@ -53,6 +52,7 @@ abstract class AbstractDatabaseObjectBuilderForm extends AbstractForm
 
     /**
      * object persisted by the most recent `save()` call
+     * @var ?TDatabaseObject
      */
     public ?DatabaseObject $object = null;
 
@@ -188,6 +188,8 @@ public function save(): void
                 ])
             );
         }
+
+        $this->afterSave();
     }
 
     #[\Override]
@@ -256,4 +258,13 @@ protected function validateSecurityToken(): void
     {
         // does nothing, is handled by `IFormDocument` object
     }
+
+    /**
+     * This method is called after a save.
+     * It can be overriden to handle additional tasks that are not handled by the default implementation.
+     */
+    protected function afterSave(): void
+    {
+        // does nothing
+    }
 }

From 0a42c91fd00d7846b300557d359f02fb36112574 Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Tue, 30 Jun 2026 17:55:05 +0200
Subject: [PATCH 12/17] Drop `DatabaseObjectBuilder::fastSave()`

The method was based on `DatabaseObjectEditor::fastCreate()` which is used very rarely and therefore is not needed in the new API.

The change simplifies the code and allows the DBO to be passed directly as a parameter to `afterCreate()` and `afterUpdate()`
---
 .../lib/data/DatabaseObjectBuilder.class.php  | 89 +++++++++----------
 .../files/lib/data/tag/TagBuilder.class.php   | 11 +--
 2 files changed, 48 insertions(+), 52 deletions(-)

diff --git a/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php b/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
index 3850c1d8c1..0b31fd8044 100644
--- a/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
+++ b/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
@@ -43,20 +43,9 @@ private function __construct(protected readonly ?DatabaseObject $object = null)
      * @return TDatabaseObject
      */
     final public function save(): DatabaseObject
-    {
-        return new (static::getBaseClass())($this->fastSave());
-    }
-
-    /**
-     * Persists the pending changes and returns the object's identifier without
-     * instantiating the full database object.
-     */
-    final public function fastSave(): int|string
     {
         if ($this->object !== null) {
-            $this->update();
-
-            return $this->object->getObjectID();
+            return $this->update();
         }
 
         return $this->create();
@@ -64,8 +53,10 @@ final public function fastSave(): int|string
 
     /**
      * Inserts a new row and returns the primary key of the created object.
+     *
+     * @return TDatabaseObject
      */
-    private function create(): int|string
+    private function create(): DatabaseObject
     {
         $keys = $values = '';
         $statementParameters = [];
@@ -94,38 +85,46 @@ private function create(): int|string
             throw new \BadMethodCallException("Missing value for '" . static::getBaseClass()::getDatabaseTableIndexName() . "'");
         }
 
-        $this->afterCreate($id);
+        $object = new (static::getBaseClass())($id);
+
+        $this->afterCreate($object);
 
-        return $id;
+        return $object;
     }
 
     /**
      * Writes the pending property changes to the existing row.
+     *
+     * @return TDatabaseObject
      */
-    private function update(): void
+    private function update(): DatabaseObject
     {
-        if ($this->properties === [] && $this->customProperties === []) {
-            return;
-        }
-
-        $updateSQL = '';
-        $statementParameters = [];
-        foreach (\array_merge($this->properties, $this->customProperties) as $key => $value) {
-            if ($updateSQL !== '') {
-                $updateSQL .= ', ';
+        if ($this->properties !== [] || $this->customProperties !== []) {
+            $updateSQL = '';
+            $statementParameters = [];
+            foreach (\array_merge($this->properties, $this->customProperties) as $key => $value) {
+                if ($updateSQL !== '') {
+                    $updateSQL .= ', ';
+                }
+                $updateSQL .= $key . ' = ?';
+                $statementParameters[] = $value;
             }
-            $updateSQL .= $key . ' = ?';
-            $statementParameters[] = $value;
-        }
-        $statementParameters[] = $this->object->getObjectID();
+            $statementParameters[] = $this->object->getObjectID();
 
-        $sql = "UPDATE  " . static::getBaseClass()::getDatabaseTableName() . "
+            $sql = "UPDATE  " . static::getBaseClass()::getDatabaseTableName() . "
                 SET     " . $updateSQL . "
                 WHERE   " . static::getBaseClass()::getDatabaseTableIndexName() . " = ?";
-        $statement = WCF::getDB()->prepare($sql);
-        $statement->execute($statementParameters);
+            $statement = WCF::getDB()->prepare($sql);
+            $statement->execute($statementParameters);
+
+            $object = new (static::getBaseClass())($this->object->getObjectID());
+        } else {
+            $object = $this->object;
+        }
+
+        $this->afterUpdate($object);
 
-        $this->afterUpdate();
+        return $object;
     }
 
     /**
@@ -165,14 +164,10 @@ final public static function delete(DatabaseObject $object): void
      * Deletes the rows identified by the given primary keys in batches inside
      * a single transaction.
      *
-     * @param (int|string)[] $objectIDs
+     * @param non-empty-list<int>|non-empty-list<string> $objectIDs
      */
-    final public static function deleteAll(array $objectIDs = []): void
+    final public static function deleteAll(array $objectIDs): void
     {
-        if ($objectIDs === []) {
-            return;
-        }
-
         static::beforeDeleteAll($objectIDs);
 
         $itemsPerLoop = 1000;
@@ -257,8 +252,10 @@ final public function setCustomProperty(string $name, string|int|float|null $val
     /**
      * This method is called after the creation of a new object.
      * It can be overriden to handle additional tasks that are not handled by the default implementation.
+     *
+     * @param TDatabaseObject $object
      */
-    protected function afterCreate(int|string $id): void
+    protected function afterCreate(DatabaseObject $object): void
     {
         // does nothing
     }
@@ -266,8 +263,10 @@ protected function afterCreate(int|string $id): void
     /**
      * This method is called after an update.
      * It can be overriden to handle additional tasks that are not handled by the default implementation.
+     *
+     * @param TDatabaseObject $object
      */
-    protected function afterUpdate(): void
+    protected function afterUpdate(DatabaseObject $object): void
     {
         // does nothing
     }
@@ -276,7 +275,7 @@ protected function afterUpdate(): void
      * This method is called before the deletion of objects.
      * It can be overriden to handle additional tasks that are not handled by the default implementation.
      *
-     * @param (int|string)[] $objectIDs
+     * @param non-empty-list<int>|non-empty-list<string> $objectIDs
      */
     protected static function beforeDeleteAll(array $objectIDs): void
     {
@@ -307,14 +306,10 @@ final public function setID(int|string $id): static
      * Updates counters for the given object.
      *
      * @param TDatabaseObject $object
-     * @param array<string, int|float> $counters
+     * @param non-empty-array<string, int|float> $counters
      */
     final public static function updateCounters(DatabaseObject $object, array $counters): void
     {
-        if ($counters === []) {
-            throw new \InvalidArgumentException("The list of counters to update must not be empty.");
-        }
-
         \assert($object instanceof (static::getBaseClass()));
 
         $updateSQL = '';
diff --git a/wcfsetup/install/files/lib/data/tag/TagBuilder.class.php b/wcfsetup/install/files/lib/data/tag/TagBuilder.class.php
index 5dc775293a..0f0ec75751 100644
--- a/wcfsetup/install/files/lib/data/tag/TagBuilder.class.php
+++ b/wcfsetup/install/files/lib/data/tag/TagBuilder.class.php
@@ -2,6 +2,7 @@
 
 namespace wcf\data\tag;
 
+use wcf\data\DatabaseObject;
 use wcf\data\DatabaseObjectBuilder;
 use wcf\system\WCF;
 
@@ -54,21 +55,21 @@ public function setSynonyms(array $synonyms): static
     }
 
     #[\Override]
-    protected function afterCreate(int|string $id): void
+    protected function afterCreate(DatabaseObject $object): void
     {
         if ($this->synonyms !== null && $this->synonyms !== []) {
-            $this->saveSynonyms(new Tag($id), $this->synonyms);
+            $this->saveSynonyms($object, $this->synonyms);
         }
     }
 
     #[\Override]
-    protected function afterUpdate(): void
+    protected function afterUpdate(DatabaseObject $object): void
     {
         if ($this->synonyms !== null) {
-            $this->removeSynonyms($this->object);
+            $this->removeSynonyms($object);
 
             if ($this->synonyms !== []) {
-                $this->saveSynonyms($this->object, $this->synonyms);
+                $this->saveSynonyms($object, $this->synonyms);
             }
         }
     }

From 43b15ffd387fbba91e1a9af0f920185baf7e91ab Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Tue, 30 Jun 2026 21:55:15 +0200
Subject: [PATCH 13/17] Add `getObject()` to `DatabaseObjectBuilder`

---
 .../files/lib/data/DatabaseObjectBuilder.class.php        | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php b/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
index 0b31fd8044..6ad5805667 100644
--- a/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
+++ b/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
@@ -329,4 +329,12 @@ final public static function updateCounters(DatabaseObject $object, array $count
         $statement = WCF::getDB()->prepare($sql);
         $statement->execute($statementParameters);
     }
+
+    /**
+     * @return ?TDatabaseObject
+     */
+    public function getObject(): ?DatabaseObject
+    {
+        return $this->object;
+    }
 }

From e81a35141ecae1dddcbd59d4631d1baa2fa86192 Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Tue, 30 Jun 2026 21:57:16 +0200
Subject: [PATCH 14/17] Allow accessing wysiwyg and attachment fields before
 the form is built

---
 .../wysiwyg/WysiwygFormContainer.class.php         | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/wcfsetup/install/files/lib/system/form/builder/container/wysiwyg/WysiwygFormContainer.class.php b/wcfsetup/install/files/lib/system/form/builder/container/wysiwyg/WysiwygFormContainer.class.php
index b474225179..89eb0757a7 100644
--- a/wcfsetup/install/files/lib/system/form/builder/container/wysiwyg/WysiwygFormContainer.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/container/wysiwyg/WysiwygFormContainer.class.php
@@ -250,14 +250,11 @@ public function enablePreviewButton(bool $enablePreviewButton = true)
      * Returns the form field handling attachments.
      *
      * @return  WysiwygAttachmentFormField
-     * @throws  \BadMethodCallException     if the form field container has not been populated yet/form has not been built yet
      */
     public function getAttachmentField()
     {
         if ($this->attachmentField === null) {
-            throw new \BadMethodCallException(
-                "Wysiwyg form field can only be requested after the form has been built for container '{$this->getId()}'."
-            );
+            $this->attachmentField = WysiwygAttachmentFormField::create($this->wysiwygId . 'Attachments');
         }
 
         return $this->attachmentField;
@@ -345,14 +342,11 @@ public function getSmiliesContainer()
      * Returns the wysiwyg form field handling the actual text.
      *
      * @return  WysiwygFormField
-     * @throws  \BadMethodCallException     if the form field container has not been populated yet/form has not been built yet
      */
     public function getWysiwygField()
     {
         if ($this->wysiwygField === null) {
-            throw new \BadMethodCallException(
-                "Wysiwyg form field can only be requested after the form has been built for container '{$this->getId()}'."
-            );
+            $this->wysiwygField = WysiwygFormField::create($this->wysiwygId);
         }
 
         return $this->wysiwygField;
@@ -469,7 +463,7 @@ public function populate()
     {
         parent::populate();
 
-        $this->wysiwygField = WysiwygFormField::create($this->wysiwygId)
+        $this->wysiwygField = $this->getWysiwygField()
             ->objectType($this->messageObjectType)
             ->minimumLength($this->getMinimumLength())
             ->maximumLength($this->getMaximumLength())
@@ -480,7 +474,7 @@ public function populate()
             ->wysiwygId($this->getWysiwygId())
             ->label('wcf.message.smilies')
             ->available($this->supportSmilies);
-        $this->attachmentField = WysiwygAttachmentFormField::create($this->wysiwygId . 'Attachments')
+        $this->attachmentField = $this->getAttachmentField()
             ->wysiwygId($this->getWysiwygId());
         $this->settingsContainer = FormContainer::create($this->wysiwygId . 'SettingsContainer')
             ->appendChildren($this->settingsNodes);

From ed0fadd7fa3874e09459cce88938d43a1cd49800 Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Tue, 30 Jun 2026 21:57:45 +0200
Subject: [PATCH 15/17] Use a dedicated template for the form field in
 save/load callback types

---
 .../lib/system/form/builder/field/IFormField.class.php      | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/wcfsetup/install/files/lib/system/form/builder/field/IFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/IFormField.class.php
index b5006af21d..44b2daacc7 100644
--- a/wcfsetup/install/files/lib/system/form/builder/field/IFormField.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/IFormField.class.php
@@ -111,7 +111,8 @@ public function getValue();
      * without triggering a contravariance error.
      *
      * @template TBuilder of DatabaseObjectBuilder
-     * @param \Closure(TBuilder, IFormField): void $callback
+     * @template TIFormField of IFormField
+     * @param \Closure(TBuilder, TIFormField): void $callback
      * @return static this field
      * @since 6.3
      */
@@ -152,7 +153,8 @@ public function getSaveValueCallback(): ?\Closure;
      * triggering a contravariance error.
      *
      * @template TObject of IStorableObject
-     * @param \Closure(TObject, IFormField): void $callback
+     * @template TIFormField of IFormField
+     * @param \Closure(TObject, TIFormField): void $callback
      * @return static this field
      * @since 6.3
      */

From a5569f38d37576a4b067e15deb6eafba0e8dca9e Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Tue, 30 Jun 2026 21:58:13 +0200
Subject: [PATCH 16/17] Honor `loadValueCallback` in
 `TI18nFormField::updatedObject()`

---
 .../builder/field/TI18nFormField.class.php    | 24 +++++++++++--------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/wcfsetup/install/files/lib/system/form/builder/field/TI18nFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/TI18nFormField.class.php
index cbec854598..0523a612f9 100644
--- a/wcfsetup/install/files/lib/system/form/builder/field/TI18nFormField.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/TI18nFormField.class.php
@@ -279,16 +279,20 @@ public function updatedObject(array $data, IStorableObject $object, bool $loadVa
             $loadValues = true;
         }
 
-        if ($loadValues && isset($data[$this->getObjectProperty()])) {
-            $value = $data[$this->getObjectProperty()];
-
-            if ($this->isI18n()) {
-                // do not use `I18nHandler::setOptions()` because then `I18nHandler` only
-                // reads the values when assigning the template variables and the values
-                // are not available in this class via `getValue()`
-                $this->setStringValue($value);
-            } else {
-                $this->value = $value;
+        if ($loadValues) {
+            if ($this->loadValueCallback !== null) {
+                ($this->loadValueCallback)($object, $this);
+            } elseif (isset($data[$this->getObjectProperty()])) {
+                $value = $data[$this->getObjectProperty()];
+
+                if ($this->isI18n()) {
+                    // do not use `I18nHandler::setOptions()` because then `I18nHandler` only
+                    // reads the values when assigning the template variables and the values
+                    // are not available in this class via `getValue()`
+                    $this->setStringValue($value);
+                } else {
+                    $this->value = $value;
+                }
             }
         }
 

From 0aaf82d85985b45bb3a0780bfdb456a08cb1bdd0 Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Wed, 1 Jul 2026 13:50:19 +0200
Subject: [PATCH 17/17] Validate required properties in
 `DatabaseObjectBuilder::create()`

---
 .../lib/data/DatabaseObjectBuilder.class.php  | 32 +++++++++++++++++++
 .../files/lib/data/tag/TagBuilder.class.php   |  6 ++++
 2 files changed, 38 insertions(+)

diff --git a/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php b/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
index 6ad5805667..0302b3f574 100644
--- a/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
+++ b/wcfsetup/install/files/lib/data/DatabaseObjectBuilder.class.php
@@ -58,6 +58,8 @@ final public function save(): DatabaseObject
      */
     private function create(): DatabaseObject
     {
+        $this->validateCreate();
+
         $keys = $values = '';
         $statementParameters = [];
         foreach (\array_merge($this->properties, $this->customProperties) as $key => $value) {
@@ -92,6 +94,36 @@ private function create(): DatabaseObject
         return $object;
     }
 
+    /**
+     * Validates that the pending changes are sufficient to create a new object.
+     *
+     * @throws \BadMethodCallException if no properties are set or a required property is missing
+     */
+    private function validateCreate(): void
+    {
+        if ($this->properties === [] && $this->customProperties === []) {
+            throw new \BadMethodCallException("Cannot create an object without any properties.");
+        }
+
+        foreach ($this->getRequiredProperties() as $property) {
+            if (!\array_key_exists($property, $this->properties)) {
+                throw new \BadMethodCallException("Missing value for required property '{$property}'.");
+            }
+        }
+    }
+
+    /**
+     * Returns the names of the properties that must be set when creating a new
+     * object. Subclasses can override this method to enforce that required
+     * values are provided before the object is persisted.
+     *
+     * @return list<string>
+     */
+    protected function getRequiredProperties(): array
+    {
+        return [];
+    }
+
     /**
      * Writes the pending property changes to the existing row.
      *
diff --git a/wcfsetup/install/files/lib/data/tag/TagBuilder.class.php b/wcfsetup/install/files/lib/data/tag/TagBuilder.class.php
index 0f0ec75751..41fc70d62a 100644
--- a/wcfsetup/install/files/lib/data/tag/TagBuilder.class.php
+++ b/wcfsetup/install/files/lib/data/tag/TagBuilder.class.php
@@ -106,4 +106,10 @@ private function saveSynonyms(Tag $tag, array $synonyms): void
             }
         }
     }
+
+    #[\Override]
+    protected function getRequiredProperties(): array
+    {
+        return ['name'];
+    }
 }