Deprecate string default expressions

UPGRADE.md

@@ -29,6 +29,95 @@ and directly start using native lazy objects.
 
 # Upgrade to 3.6
 
+## Deprecate using string expression for default values in mappings
+
+Using a string expression for default values in field mappings is deprecated.
+Use `Doctrine\DBAL\Schema\DefaultExpression` instances instead.
+
+Here is how to address this deprecation when mapping entities using PHP attributes:
+
+```diff
+ use DateTime;
++use Doctrine\DBAL\Schema\DefaultExpression\CurrentDate;
++use Doctrine\DBAL\Schema\DefaultExpression\CurrentTime;
++use Doctrine\DBAL\Schema\DefaultExpression\CurrentTimestamp;
+ use Doctrine\ORM\Mapping as ORM;
+
+ #[ORM\Entity]
+ final class TimeEntity
+ {
+     #[ORM\Id]
+     #[ORM\Column]
+     public int $id;
+
+-    #[ORM\Column(options: ['default' => 'CURRENT_TIMESTAMP'], insertable: false, updatable: false)]
++    #[ORM\Column(options: ['default' => new CurrentTimestamp()], insertable: false, updatable: false)]
+     public DateTime $createdAt;
+
+-    #[ORM\Column(options: ['default' => 'CURRENT_TIME'], insertable: false, updatable: false)]
++    #[ORM\Column(options: ['default' => new CurrentTime()], insertable: false, updatable: false)]
+     public DateTime $createdTime;
+
+-    #[ORM\Column(options: ['default' => 'CURRENT_DATE'], insertable: false, updatable: false)]
++    #[ORM\Column(options: ['default' => new CurrentDate()], insertable: false, updatable: false)]
+     public DateTime $createdDate;
+ }
+```
+
+Here is how to do the same when mapping entities using XML:
+
+```diff
+ <?xml version="1.0" encoding="UTF-8"?>
+
+ <doctrine-mapping xmlns="http://doctrine-project.org/schemas/orm/doctrine-mapping"
+                   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+                   xsi:schemaLocation="http://doctrine-project.org/schemas/orm/doctrine-mapping
+                           https://www.doctrine-project.org/schemas/orm/doctrine-mapping.xsd">
+
+     <entity name="Doctrine\Tests\ORM\Functional\XmlTimeEntity">
+         <id name="id" type="integer" column="id">
+             <generator strategy="AUTO"/>
+         </id>
+
+         <field name="createdAt" type="datetime" insertable="false" updatable="false">
+             <options>
+-                <option name="default">CURRENT_TIMESTAMP</option>
++                <option name="default">
++                    <object class="Doctrine\DBAL\Schema\DefaultExpression\CurrentTimestamp"/>
++                </option>
+             </options>
+         </field>
+
+         <field name="createdAtImmutable" type="datetime_immutable" insertable="false" updatable="false">
+             <options>
+-                <option name="default">CURRENT_TIMESTAMP</option>
++                <option name="default">
++                    <object class="Doctrine\DBAL\Schema\DefaultExpression\CurrentTimestamp"/>
++                </option>
+             </options>
+         </field>
+
+         <field name="createdTime" type="time" insertable="false" updatable="false">
+             <options>
+-                <option name="default">CURRENT_TIME</option>
++                <option name="default">
++                    <object class="Doctrine\DBAL\Schema\DefaultExpression\CurrentTime"/>
++                </option>
+             </options>
+         </field>
+         <field name="createdDate" type="date" insertable="false" updatable="false">
+             <options>
+-                <option name="default">CURRENT_DATE</option>
++                <option name="default">
++                    <object class="Doctrine\DBAL\Schema\DefaultExpression\CurrentDate"/>
++                </option>
+             </options>
+         </field>
+     </entity>
+ </doctrine-mapping>
+```
+
+
 ## Deprecate `FieldMapping::$default`
 
 The `default` property of `Doctrine\ORM\Mapping\FieldMapping` is deprecated and

docs/en/reference/basic-mapping.rst

@@ -190,6 +190,22 @@ PHP class, Doctrine also allows you to specify default values for
 database columns using the ``default`` key in the ``options`` array of
 the ``Column`` attribute.
 
+When using XML, you can specify object instances using the ``<object>``
+element:
+
+.. code-block:: xml
+
+    <field name="createdAt" type="datetime" insertable="false" updatable="false">
+        <options>
+            <option name="default">
+                <object class="Doctrine\DBAL\Schema\DefaultExpression\CurrentTimestamp"/>
+            </option>
+        </options>
+    </field>
+
+The ``<object>`` element requires a ``class`` attribute specifying the
+fully qualified class name to instantiate.
+
 .. configuration-block::
    .. literalinclude:: basic-mapping/DefaultValues.php
        :language: attribute

docs/en/reference/basic-mapping/DefaultValues.php

@@ -4,6 +4,8 @@
 
 namespace App\Entity;
 
+use DateTime;
+use Doctrine\DBAL\Schema\DefaultExpression\CurrentTimestamp;
 use Doctrine\ORM\Mapping\Column;
 use Doctrine\ORM\Mapping\Entity;
 
@@ -12,4 +14,7 @@ class Message
 {
     #[Column(options: ['default' => 'Hello World!'])]
     private string $text;
+
+    #[Column(options: ['default' => new CurrentTimestamp()], insertable: false, updatable: false)]
+    private DateTime $createdAt;
 }

docs/en/reference/basic-mapping/default-values.xml

@@ -5,5 +5,12 @@
         <option name="default">Hello World!</option>
       </options>
     </field>
+    <field name="createdAt" insertable="false" updatable="false">
+      <options>
+        <option name="default">
+            <object class="Doctrine\DBAL\Schema\DefaultExpression\CurrentTimestamp"/>
+        </option>
+      </options>
+    </field>
   </entity>
 </doctrine-mapping>

doctrine-mapping.xsd

@@ -155,10 +155,20 @@
     </xs:restriction>
   </xs:simpleType>
 
+  <xs:complexType name="object">
+    <xs:attribute name="class" type="xs:string" use="required"/>
+    <xs:anyAttribute namespace="##other"/>
+  </xs:complexType>
+
   <xs:complexType name="option" mixed="true">
-    <xs:choice minOccurs="0" maxOccurs="unbounded">
-      <xs:element name="option" type="orm:option"/>
-      <xs:any minOccurs="0" maxOccurs="unbounded" namespace="##other"/>
+    <xs:choice minOccurs="0" maxOccurs="1">
+      <xs:element name="object" type="orm:object"/>
+      <xs:sequence>
+        <xs:choice minOccurs="0" maxOccurs="unbounded">
+          <xs:element name="option" type="orm:option"/>
+          <xs:any minOccurs="0" maxOccurs="unbounded" namespace="##other"/>
+        </xs:choice>
+      </xs:sequence>
     </xs:choice>
     <xs:attribute name="name" type="xs:NMTOKEN" use="required"/>
     <xs:anyAttribute namespace="##other"/>

phpstan-baseline.neon

@@ -1441,7 +1441,7 @@ parameters:
 			path: src/Mapping/Driver/XmlDriver.php
 
 		-
-			message: '#^Parameter \#1 \$columnDef of method Doctrine\\ORM\\Mapping\\ClassMetadata\<T of object\>\:\:setDiscriminatorColumn\(\) expects array\{name\: string\|null, fieldName\?\: string\|null, type\?\: string\|null, length\?\: int\|null, columnDefinition\?\: string\|null, enumType\?\: class\-string\<BackedEnum\>\|null, options\?\: array\<string, mixed\>\|null\}\|Doctrine\\ORM\\Mapping\\DiscriminatorColumnMapping\|null, array\{name\: string\|null, type\: string, length\: int, columnDefinition\: string\|null, enumType\: string\|null, options\?\: array\<int\|string, array\<int\|string, mixed\>\|bool\|string\>\} given\.$#'
+			message: '#^Parameter \#1 \$columnDef of method Doctrine\\ORM\\Mapping\\ClassMetadata\<T of object\>\:\:setDiscriminatorColumn\(\) expects array\{name\: string\|null, fieldName\?\: string\|null, type\?\: string\|null, length\?\: int\|null, columnDefinition\?\: string\|null, enumType\?\: class\-string\<BackedEnum\>\|null, options\?\: array\<string, mixed\>\|null\}\|Doctrine\\ORM\\Mapping\\DiscriminatorColumnMapping\|null, array\{name\: string\|null, type\: string, length\: int, columnDefinition\: string\|null, enumType\: string\|null, options\?\: array\<int\|string, array\<int\|string, mixed\>\|bool\|object\|string\>\} given\.$#'
 			identifier: argument.type
 			count: 1
 			path: src/Mapping/Driver/XmlDriver.php
@@ -1471,7 +1471,7 @@ parameters:
 			path: src/Mapping/Driver/XmlDriver.php
 
 		-
-			message: '#^Property Doctrine\\ORM\\Mapping\\ClassMetadata\<T of object\>\:\:\$table \(array\{name\: string, schema\?\: string, indexes\?\: array, uniqueConstraints\?\: array, options\?\: array\<string, mixed\>, quoted\?\: bool\}\) does not accept array\{name\: string, schema\?\: string, indexes\?\: array, uniqueConstraints\?\: array, options\: array\<int\|string, array\<int\|string, mixed\>\|bool\|string\>, quoted\?\: bool\}\.$#'
+			message: '#^Property Doctrine\\ORM\\Mapping\\ClassMetadata\<T of object\>\:\:\$table \(array\{name\: string, schema\?\: string, indexes\?\: array, uniqueConstraints\?\: array, options\?\: array\<string, mixed\>, quoted\?\: bool\}\) does not accept array\{name\: string, schema\?\: string, indexes\?\: array, uniqueConstraints\?\: array, options\: array\<int\|string, array\<int\|string, mixed\>\|bool\|object\|string\>, quoted\?\: bool\}\.$#'
 			identifier: assign.propertyType
 			count: 1
 			path: src/Mapping/Driver/XmlDriver.php

src/Mapping/Driver/XmlDriver.php

@@ -16,6 +16,7 @@
 use SimpleXMLElement;
 
 use function assert;
+use function class_exists;
 use function constant;
 use function count;
 use function defined;
@@ -656,15 +657,30 @@ public function loadMetadataForClass($className, PersistenceClassMetadata $metad
      * Parses (nested) option elements.
      *
      * @return mixed[] The options array.
-     * @phpstan-return array<int|string, array<int|string, mixed|string>|bool|string>
+     * @phpstan-return array<int|string, array<int|string, mixed|string>|bool|string|object>
      */
     private function parseOptions(SimpleXMLElement|null $options): array
     {
         $array = [];
 
         foreach ($options ?? [] as $option) {
+            $value = null;
             if ($option->count()) {
-                $value = $this->parseOptions($option->children());
+                // Check if this option contains an <object> element
+                $children         = $option->children();
+                $hasObjectElement = false;
+
+                foreach ($children as $child) {
+                    if ($child->getName() === 'object') {
+                        $value            = $this->parseObjectElement($child);
+                        $hasObjectElement = true;
+                        break;
+                    }
+                }
+
+                if (! $hasObjectElement) {
+                    $value = $this->parseOptions($children);
+                }
             } else {
                 $value = (string) $option;
             }
@@ -684,6 +700,33 @@ private function parseOptions(SimpleXMLElement|null $options): array
         return $array;
     }
 
+    /**
+     * Parses an <object> element and returns the instantiated object.
+     *
+     * @param SimpleXMLElement $objectElement The XML element.
+     *
+     * @return object The instantiated object.
+     *
+     * @throws MappingException If the object specification is invalid.
+     * @throws InvalidArgumentException If the class does not exist.
+     */
+    private function parseObjectElement(SimpleXMLElement $objectElement): object
+    {
+        $attributes = $objectElement->attributes();
+
+        if (! isset($attributes->class)) {
+            throw MappingException::missingRequiredOption('object', 'class');
+        }
+
+        $className = (string) $attributes->class;
+
+        if (! class_exists($className)) {
+            throw new InvalidArgumentException(sprintf('Class "%s" does not exist', $className));
+        }
+
+        return new $className();
+    }
+
     /**
      * Constructs a joinColumn mapping array based on the information
      * found in the given SimpleXMLElement.

src/Tools/SchemaTool.php

@@ -23,6 +23,7 @@
 use Doctrine\DBAL\Schema\Schema;
 use Doctrine\DBAL\Schema\Table;
 use Doctrine\DBAL\Types\Types;
+use Doctrine\Deprecations\Deprecation;
 use Doctrine\ORM\EntityManagerInterface;
 use Doctrine\ORM\Mapping\AssociationMapping;
 use Doctrine\ORM\Mapping\ClassMetadata;
@@ -507,20 +508,50 @@ private function gatherColumn(
                 ], true)
                 && $options['default'] === $this->platform->getCurrentTimestampSQL()
             ) {
+                Deprecation::trigger(
+                    'doctrine/orm',
+                    'https://github.com/doctrine/orm/issues/12252',
+                    <<<'DEPRECATION'
+                    Using "%s" as a default value for datetime fields is deprecated and
+                    will not be supported in Doctrine ORM 4.0.
+                    Pass a `Doctrine\DBAL\Schema\DefaultExpression\CurrentTimestamp` instance instead.
+                    DEPRECATION,
+                    $this->platform->getCurrentTimestampSQL(),
+                );
                 $options['default'] = new CurrentTimestamp();
             }
 
             if (
                 in_array($mapping->type, [Types::TIME_MUTABLE, Types::TIME_IMMUTABLE], true)
                 && $options['default'] === $this->platform->getCurrentTimeSQL()
             ) {
+                Deprecation::trigger(
+                    'doctrine/orm',
+                    'https://github.com/doctrine/orm/issues/12252',
+                    <<<'DEPRECATION'
+                    Using "%s" as a default value for time fields is deprecated and
+                    will not be supported in Doctrine ORM 4.0.
+                    Pass a `Doctrine\DBAL\Schema\DefaultExpression\CurrentTime` instance instead.
+                    DEPRECATION,
+                    $this->platform->getCurrentTimeSQL(),
+                );
                 $options['default'] = new CurrentTime();
             }
 
             if (
                 in_array($mapping->type, [Types::DATE_MUTABLE, Types::DATE_IMMUTABLE], true)
                 && $options['default'] === $this->platform->getCurrentDateSQL()
             ) {
+                Deprecation::trigger(
+                    'doctrine/orm',
+                    'https://github.com/doctrine/orm/issues/12252',
+                    <<<'DEPRECATION'
+                    Using "%s" as a default value for date fields is deprecated and
+                    will not be supported in Doctrine ORM 4.0.
+                    Pass a `Doctrine\DBAL\Schema\DefaultExpression\CurrentDate` instance instead.
+                    DEPRECATION,
+                    $this->platform->getCurrentDateSQL(),
+                );
                 $options['default'] = new CurrentDate();
             }
         }