feat(OCP): Consumable vs. Implementable public API

build/psalm/OcpSinceChecker.php

@@ -20,7 +20,18 @@ public static function afterClassLikeVisit(AfterClassLikeVisitEvent $event): voi
 		$classLike = $event->getStmt();
 		$statementsSource = $event->getStatementsSource();
 
-		self::checkClassComment($classLike, $statementsSource);
+		if (!str_contains($statementsSource->getFilePath(), '/lib/public/')) {
+			return;
+		}
+
+		$isTesting = str_contains($statementsSource->getFilePath(), '/lib/public/Notification/')
+			|| str_contains($statementsSource->getFilePath(), 'CalendarEventStatus');
+
+		if ($isTesting) {
+			self::checkStatementAttributes($classLike, $statementsSource);
+		} else {
+			self::checkClassComment($classLike, $statementsSource);
+		}
 
 		foreach ($classLike->stmts as $stmt) {
 			if ($stmt instanceof ClassConst) {
@@ -32,11 +43,64 @@ public static function afterClassLikeVisit(AfterClassLikeVisitEvent $event): voi
 			}
 
 			if ($stmt instanceof EnumCase) {
-				self::checkStatementComment($stmt, $statementsSource, 'enum');
+				if ($isTesting) {
+					self::checkStatementAttributes($classLike, $statementsSource);
+				} else {
+					self::checkStatementComment($stmt, $statementsSource, 'enum');
+				}
 			}
 		}
 	}
 
+	private static function checkStatementAttributes(ClassLike $stmt, FileSource $statementsSource): void {
+		$hasAppFrameworkAttribute = false;
+		$mustBeConsumable = false;
+		$isConsumable = false;
+		foreach ($stmt->attrGroups as $attrGroup) {
+			foreach ($attrGroup->attrs as $attr) {
+				if (in_array($attr->name->getLast(), [
+					'Catchable',
+					'Consumable',
+					'Dispatchable',
+					'Implementable',
+					'Listenable',
+					'Throwable',
+				], true)) {
+					$hasAppFrameworkAttribute = true;
+					self::checkAttributeHasValidSinceVersion($attr, $statementsSource);
+				}
+				if (in_array($attr->name->getLast(), [
+					'Catchable',
+					'Consumable',
+					'Listenable',
+				], true)) {
+					$isConsumable = true;
+				}
+				if ($attr->name->getLast() === 'ExceptionalImplementable') {
+					$mustBeConsumable = true;
+				}
+			}
+		}
+
+		if ($mustBeConsumable && !$isConsumable) {
+			IssueBuffer::maybeAdd(
+				new InvalidDocblock(
+					'Attribute OCP\\AppFramework\\Attribute\\ExceptionalImplementable is only valid on classes that also have OCP\\AppFramework\\Attribute\\Consumable',
+					new CodeLocation($statementsSource, $stmt)
+				)
+			);
+		}
+
+		if (!$hasAppFrameworkAttribute) {
+			IssueBuffer::maybeAdd(
+				new InvalidDocblock(
+					'At least one of the OCP\\AppFramework\\Attribute attributes is required',
+					new CodeLocation($statementsSource, $stmt)
+				)
+			);
+		}
+	}
+
 	private static function checkClassComment(ClassLike $stmt, FileSource $statementsSource): void {
 		$docblock = $stmt->getDocComment();
 
@@ -124,4 +188,28 @@ private static function checkStatementComment(Stmt $stmt, FileSource $statements
 			);
 		}
 	}
+
+	private static function checkAttributeHasValidSinceVersion(\PhpParser\Node\Attribute $stmt, FileSource $statementsSource): void {
+		foreach ($stmt->args as $arg) {
+			if ($arg->name?->name === 'since') {
+				if (!$arg->value instanceof \PhpParser\Node\Scalar\String_) {
+					IssueBuffer::maybeAdd(
+						new InvalidDocblock(
+							'Attribute since argument is not a valid version string',
+							new CodeLocation($statementsSource, $stmt)
+						)
+					);
+				} else {
+					if (!preg_match('/^[1-9][0-9]*(\.[0-9]+){0,3}$/', $arg->value->value)) {
+						IssueBuffer::maybeAdd(
+							new InvalidDocblock(
+								'Attribute since argument is not a valid version string',
+								new CodeLocation($statementsSource, $stmt)
+							)
+						);
+					}
+				}
+			}
+		}
+	}
 }

lib/composer/composer/autoload_classmap.php

@@ -58,6 +58,14 @@
     'OCP\\Activity\\ISetting' => $baseDir . '/lib/public/Activity/ISetting.php',
     'OCP\\AppFramework\\ApiController' => $baseDir . '/lib/public/AppFramework/ApiController.php',
     'OCP\\AppFramework\\App' => $baseDir . '/lib/public/AppFramework/App.php',
+    'OCP\\AppFramework\\Attribute\\ASince' => $baseDir . '/lib/public/AppFramework/Attribute/ASince.php',
+    'OCP\\AppFramework\\Attribute\\Catchable' => $baseDir . '/lib/public/AppFramework/Attribute/Catchable.php',
+    'OCP\\AppFramework\\Attribute\\Consumable' => $baseDir . '/lib/public/AppFramework/Attribute/Consumable.php',
+    'OCP\\AppFramework\\Attribute\\Dispatchable' => $baseDir . '/lib/public/AppFramework/Attribute/Dispatchable.php',
+    'OCP\\AppFramework\\Attribute\\ExceptionalImplementable' => $baseDir . '/lib/public/AppFramework/Attribute/ExceptionalImplementable.php',
+    'OCP\\AppFramework\\Attribute\\Implementable' => $baseDir . '/lib/public/AppFramework/Attribute/Implementable.php',
+    'OCP\\AppFramework\\Attribute\\Listenable' => $baseDir . '/lib/public/AppFramework/Attribute/Listenable.php',
+    'OCP\\AppFramework\\Attribute\\Throwable' => $baseDir . '/lib/public/AppFramework/Attribute/Throwable.php',
     'OCP\\AppFramework\\AuthPublicShareController' => $baseDir . '/lib/public/AppFramework/AuthPublicShareController.php',
     'OCP\\AppFramework\\Bootstrap\\IBootContext' => $baseDir . '/lib/public/AppFramework/Bootstrap/IBootContext.php',
     'OCP\\AppFramework\\Bootstrap\\IBootstrap' => $baseDir . '/lib/public/AppFramework/Bootstrap/IBootstrap.php',

lib/composer/composer/autoload_static.php

@@ -99,6 +99,14 @@ class ComposerStaticInit749170dad3f5e7f9ca158f5a9f04f6a2
         'OCP\\Activity\\ISetting' => __DIR__ . '/../../..' . '/lib/public/Activity/ISetting.php',
         'OCP\\AppFramework\\ApiController' => __DIR__ . '/../../..' . '/lib/public/AppFramework/ApiController.php',
         'OCP\\AppFramework\\App' => __DIR__ . '/../../..' . '/lib/public/AppFramework/App.php',
+        'OCP\\AppFramework\\Attribute\\ASince' => __DIR__ . '/../../..' . '/lib/public/AppFramework/Attribute/ASince.php',
+        'OCP\\AppFramework\\Attribute\\Catchable' => __DIR__ . '/../../..' . '/lib/public/AppFramework/Attribute/Catchable.php',
+        'OCP\\AppFramework\\Attribute\\Consumable' => __DIR__ . '/../../..' . '/lib/public/AppFramework/Attribute/Consumable.php',
+        'OCP\\AppFramework\\Attribute\\Dispatchable' => __DIR__ . '/../../..' . '/lib/public/AppFramework/Attribute/Dispatchable.php',
+        'OCP\\AppFramework\\Attribute\\ExceptionalImplementable' => __DIR__ . '/../../..' . '/lib/public/AppFramework/Attribute/ExceptionalImplementable.php',
+        'OCP\\AppFramework\\Attribute\\Implementable' => __DIR__ . '/../../..' . '/lib/public/AppFramework/Attribute/Implementable.php',
+        'OCP\\AppFramework\\Attribute\\Listenable' => __DIR__ . '/../../..' . '/lib/public/AppFramework/Attribute/Listenable.php',
+        'OCP\\AppFramework\\Attribute\\Throwable' => __DIR__ . '/../../..' . '/lib/public/AppFramework/Attribute/Throwable.php',
         'OCP\\AppFramework\\AuthPublicShareController' => __DIR__ . '/../../..' . '/lib/public/AppFramework/AuthPublicShareController.php',
         'OCP\\AppFramework\\Bootstrap\\IBootContext' => __DIR__ . '/../../..' . '/lib/public/AppFramework/Bootstrap/IBootContext.php',
         'OCP\\AppFramework\\Bootstrap\\IBootstrap' => __DIR__ . '/../../..' . '/lib/public/AppFramework/Bootstrap/IBootstrap.php',

lib/public/AppFramework/Attribute/ASince.php

@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\AppFramework\Attribute;
+
+use Attribute;
+
+/**
+ * Abstract base attribute to declare an API's stability.
+ *
+ * @since 32.0.0
+ */
+#[Consumable(since: '32.0.0')]
+abstract class ASince {
+	/**
+	 * @param string $since For shipped apps and server code such as core/ and lib/,
+	 *                      this should be the server version. For other apps it
+	 *                      should be the semantic app version.
+	 */
+	public function __construct(
+		protected string $since,
+	) {
+	}
+
+	public function getSince(): string {
+		return $this->since;
+	}
+}

lib/public/AppFramework/Attribute/Catchable.php

@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\AppFramework\Attribute;
+
+use Attribute;
+
+/**
+ * Attribute to declare that the exception is "catchable" by apps.
+ *
+ * @since 32.0.0
+ */
+#[Attribute(Attribute::TARGET_ALL | Attribute::IS_REPEATABLE)]
+#[Consumable(since: '32.0.0')]
+#[Implementable(since: '32.0.0')]
+class Catchable extends ASince {
+}

lib/public/AppFramework/Attribute/Consumable.php

@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\AppFramework\Attribute;
+
+use Attribute;
+
+/**
+ * Attribute to declare that the API stability is limited to "consuming" the
+ * class, interface, enum, etc. Apps are not allowed to implement or replace them.
+ *
+ * For events use @see \OCP\AppFramework\Attribute\Listenable
+ * For exceptions use @see \OCP\AppFramework\Attribute\Catchable
+ *
+ * @since 32.0.0
+ */
+#[Attribute(Attribute::TARGET_ALL | Attribute::IS_REPEATABLE)]
+#[Consumable(since: '32.0.0')]
+#[Implementable(since: '32.0.0')]
+class Consumable extends ASince {
+}

lib/public/AppFramework/Attribute/Dispatchable.php

@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\AppFramework\Attribute;
+
+use Attribute;
+
+/**
+ * Attribute to declare that the event is "dispatchable" by apps.
+ *
+ * @since 32.0.0
+ */
+#[Attribute(Attribute::TARGET_ALL | Attribute::IS_REPEATABLE)]
+#[Consumable(since: '32.0.0')]
+#[Implementable(since: '32.0.0')]
+class Dispatchable extends ASince {
+}

lib/public/AppFramework/Attribute/ExceptionalImplementable.php

@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\AppFramework\Attribute;
+
+use Attribute;
+
+/**
+ * Attribute to declare that the API marked as Consumable/Listenable/Catchable
+ * has an exception and is Implementable/Dispatchable/Throwable by a dedicated
+ * app. Changes to such an API have to be communicated to the affected app maintainers.
+ *
+ * @since 32.0.0
+ */
+#[Attribute(Attribute::TARGET_ALL | Attribute::IS_REPEATABLE)]
+#[Consumable(since: '32.0.0')]
+#[Implementable(since: '32.0.0')]
+class ExceptionalImplementable {
+	public function __construct(
+		protected string $app,
+		protected ?string $class = null,
+	) {
+	}
+
+	public function getApp(): string {
+		return $this->app;
+	}
+
+	public function getClass(): ?string {
+		return $this->class;
+	}
+}

lib/public/AppFramework/Attribute/Implementable.php

@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\AppFramework\Attribute;
+
+use Attribute;
+
+/**
+ * Attribute to declare that the API stability is limited to "implementing" the
+ * class, interface, enum, etc.
+ *
+ * For events use @see \OCP\AppFramework\Attribute\Dispatchable
+ * For exceptions use @see \OCP\AppFramework\Attribute\Throwable
+ *
+ * @since 32.0.0
+ */
+#[Attribute(Attribute::TARGET_ALL | Attribute::IS_REPEATABLE)]
+#[Consumable(since: '32.0.0')]
+#[Implementable(since: '32.0.0')]
+class Implementable extends ASince {
+}

lib/public/AppFramework/Attribute/Listenable.php

@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\AppFramework\Attribute;
+
+use Attribute;
+
+/**
+ * Attribute to declare that the event is "listenable" by apps.
+ *
+ * @since 32.0.0
+ */
+#[Attribute(Attribute::TARGET_ALL | Attribute::IS_REPEATABLE)]
+#[Consumable(since: '32.0.0')]
+#[Implementable(since: '32.0.0')]
+class Listenable extends ASince {
+}

lib/public/AppFramework/Attribute/Throwable.php

@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\AppFramework\Attribute;
+
+use Attribute;
+
+/**
+ * Attribute to declare that the exception is "throwable" by apps.
+ *
+ * @since 32.0.0
+ */
+#[Attribute(Attribute::TARGET_ALL | Attribute::IS_REPEATABLE)]
+#[Consumable(since: '32.0.0')]
+#[Implementable(since: '32.0.0')]
+class Throwable extends ASince {
+}

lib/public/Calendar/CalendarEventStatus.php

@@ -7,11 +7,9 @@
  */
 namespace OCP\Calendar;
 
-/**
- * The status of a calendar event.
- *
- * @since 32.0.0
- */
+use OCP\AppFramework\Attribute\Listenable;
+
+#[Listenable(since: '32.0.0')]
 enum CalendarEventStatus: string {
 	case TENTATIVE = 'TENTATIVE';
 	case CONFIRMED = 'CONFIRMED';

lib/public/Notification/AlreadyProcessedException.php

@@ -8,9 +8,9 @@
  */
 namespace OCP\Notification;
 
-/**
- * @since 17.0.0
- */
+use OCP\AppFramework\Attribute\Throwable;
+
+#[Throwable(since: '17.0.0')]
 class AlreadyProcessedException extends \RuntimeException {
 	/**
 	 * @since 17.0.0