fix: promote re-shares when deleting the parent share

apps/files/lib/Service/OwnershipTransferService.php

@@ -147,16 +147,6 @@ public function transfer(
 			$output
 		);
 
-		$destinationPath = $finalTarget . '/' . $path;
-		// restore the shares
-		$this->restoreShares(
-			$sourceUid,
-			$destinationUid,
-			$destinationPath,
-			$shares,
-			$output
-		);
-
 		// transfer the incoming shares
 		if ($transferIncomingShares === true) {
 			$sourceShares = $this->collectIncomingShares(
@@ -181,6 +171,16 @@ public function transfer(
 				$move
 			);
 		}
+
+		$destinationPath = $finalTarget . '/' . $path;
+		// restore the shares
+		$this->restoreShares(
+			$sourceUid,
+			$destinationUid,
+			$destinationPath,
+			$shares,
+			$output
+		);
 	}
 
 	private function sanitizeFolderName(string $name): string {

apps/files_sharing/tests/EtagPropagationTest.php

@@ -277,7 +277,8 @@ public function testOwnerUnshares(): void {
 			self::TEST_FILES_SHARING_API_USER2,
 		]);
 
-		$this->assertAllUnchanged();
+		$this->assertEtagsNotChanged([self::TEST_FILES_SHARING_API_USER1, self::TEST_FILES_SHARING_API_USER2, self::TEST_FILES_SHARING_API_USER3]);
+		$this->assertEtagsChanged([self::TEST_FILES_SHARING_API_USER4]);
 	}
 
 	public function testOwnerUnsharesFlatReshares(): void {

lib/private/Share20/Manager.php

@@ -18,6 +18,7 @@
 use OCP\Files\IRootFolder;
 use OCP\Files\Mount\IMountManager;
 use OCP\Files\Node;
+use OCP\Files\NotFoundException;
 use OCP\HintException;
 use OCP\IConfig;
 use OCP\IDateTimeZone;
@@ -782,6 +783,7 @@ public function createShare(IShare $share) {
 	 * @param IShare $share
 	 * @return IShare The share object
 	 * @throws \InvalidArgumentException
+	 * @throws GenericShareException
 	 */
 	public function updateShare(IShare $share) {
 		$expirationDateUpdated = false;
@@ -1039,6 +1041,81 @@ protected function deleteChildren(IShare $share) {
 		return $deletedShares;
 	}
 
+	/** Promote re-shares into direct shares so that target user keeps access */
+	protected function promoteReshares(IShare $share): void {
+		try {
+			$node = $share->getNode();
+		} catch (NotFoundException) {
+			/* Skip if node not found */
+			return;
+		}
+
+		$userIds = [];
+
+		if ($share->getShareType() === IShare::TYPE_USER) {
+			$userIds[] = $share->getSharedWith();
+		} elseif ($share->getShareType() === IShare::TYPE_GROUP) {
+			$group = $this->groupManager->get($share->getSharedWith());
+			$users = $group?->getUsers() ?? [];
+
+			foreach ($users as $user) {
+				/* Skip share owner */
+				if ($user->getUID() === $share->getShareOwner() || $user->getUID() === $share->getSharedBy()) {
+					continue;
+				}
+				$userIds[] = $user->getUID();
+			}
+		} else {
+			/* We only support user and group shares */
+			return;
+		}
+
+		$reshareRecords = [];
+		$shareTypes = [
+			IShare::TYPE_GROUP,
+			IShare::TYPE_USER,
+			IShare::TYPE_LINK,
+			IShare::TYPE_REMOTE,
+			IShare::TYPE_EMAIL,
+		];
+
+		foreach ($userIds as $userId) {
+			foreach ($shareTypes as $shareType) {
+				$provider = $this->factory->getProviderForType($shareType);
+				$shares = $provider->getSharesBy($userId, $shareType, $node, false, -1, 0);
+				foreach ($shares as $child) {
+					$reshareRecords[] = $child;
+				}
+			}
+
+			if ($node instanceof Folder) {
+				$sharesInFolder = $this->getSharesInFolder($userId, $node, false);
+
+				foreach ($sharesInFolder as $shares) {
+					foreach ($shares as $child) {
+						$reshareRecords[] = $child;
+					}
+				}
+			}
+		}
+
+		foreach ($reshareRecords as $child) {
+			try {
+				/* Check if the share is still valid (means the resharer still has access to the file through another mean) */
+				$this->generalCreateChecks($child);
+			} catch (GenericShareException $e) {
+				/* The check is invalid, promote it to a direct share from the sharer of parent share */
+				$this->logger->debug('Promote reshare because of exception ' . $e->getMessage(), ['exception' => $e, 'fullId' => $child->getFullId()]);
+				try {
+					$child->setSharedBy($share->getSharedBy());
+					$this->updateShare($child);
+				} catch (GenericShareException|\InvalidArgumentException $e) {
+					$this->logger->warning('Failed to promote reshare because of exception ' . $e->getMessage(), ['exception' => $e, 'fullId' => $child->getFullId()]);
+				}
+			}
+		}
+	}
+
 	/**
 	 * Delete a share
 	 *
@@ -1063,6 +1140,9 @@ public function deleteShare(IShare $share) {
 		$provider->delete($share);
 
 		$this->dispatcher->dispatchTyped(new ShareDeletedEvent($share));
+
+		// Promote reshares of the deleted share
+		$this->promoteReshares($share);
 	}
 
 

tests/lib/Share20/ManagerTest.php

@@ -46,6 +46,7 @@
 use OCP\Share\Events\ShareDeletedEvent;
 use OCP\Share\Events\ShareDeletedFromSelfEvent;
 use OCP\Share\Exceptions\AlreadySharedException;
+use OCP\Share\Exceptions\GenericShareException;
 use OCP\Share\Exceptions\ShareNotFound;
 use OCP\Share\IManager;
 use OCP\Share\IProviderFactory;
@@ -227,7 +228,7 @@ public function dataTestDelete() {
 	 */
 	public function testDelete($shareType, $sharedWith): void {
 		$manager = $this->createManagerMock()
-			->setMethods(['getShareById', 'deleteChildren'])
+			->setMethods(['getShareById', 'deleteChildren', 'promoteReshares'])
 			->getMock();
 
 		$manager->method('deleteChildren')->willReturn([]);
@@ -245,6 +246,7 @@ public function testDelete($shareType, $sharedWith): void {
 			->setTarget('myTarget');
 
 		$manager->expects($this->once())->method('deleteChildren')->with($share);
+		$manager->expects($this->once())->method('promoteReshares')->with($share);
 
 		$this->defaultProvider
 			->expects($this->once())
@@ -269,7 +271,7 @@ public function testDelete($shareType, $sharedWith): void {
 
 	public function testDeleteLazyShare(): void {
 		$manager = $this->createManagerMock()
-			->setMethods(['getShareById', 'deleteChildren'])
+			->setMethods(['getShareById', 'deleteChildren', 'promoteReshares'])
 			->getMock();
 
 		$manager->method('deleteChildren')->willReturn([]);
@@ -288,6 +290,7 @@ public function testDeleteLazyShare(): void {
 		$this->rootFolder->expects($this->never())->method($this->anything());
 
 		$manager->expects($this->once())->method('deleteChildren')->with($share);
+		$manager->expects($this->once())->method('promoteReshares')->with($share);
 
 		$this->defaultProvider
 			->expects($this->once())
@@ -312,7 +315,7 @@ public function testDeleteLazyShare(): void {
 
 	public function testDeleteNested(): void {
 		$manager = $this->createManagerMock()
-			->setMethods(['getShareById'])
+			->setMethods(['getShareById', 'promoteReshares'])
 			->getMock();
 
 		$path = $this->createMock(File::class);
@@ -469,6 +472,115 @@ public function testDeleteChildren(): void {
 		$this->assertSame($shares, $result);
 	}
 
+	public function testPromoteReshareWhenUserHasOneShare(): void {
+		$manager = $this->createManagerMock()
+			->setMethods(['updateShare', 'getSharesInFolder', 'generalCreateChecks'])
+			->getMock();
+
+		$folder = $this->createMock(Folder::class);
+
+		$share = $this->createMock(IShare::class);
+		$share->method('getShareType')->willReturn(IShare::TYPE_USER);
+		$share->method('getNodeType')->willReturn('folder');
+		$share->method('getSharedWith')->willReturn('UserB');
+		$share->method('getNode')->willReturn($folder);
+
+		$reShare = $this->createMock(IShare::class);
+		$reShare->method('getSharedBy')->willReturn('UserB');
+		$reShare->method('getSharedWith')->willReturn('UserC');
+		$reShare->method('getNode')->willReturn($folder);
+
+		$reShareInSubFolder = $this->createMock(IShare::class);
+		$reShareInSubFolder->method('getSharedBy')->willReturn('UserB');
+
+		$manager->method('getSharesInFolder')->willReturn([$reShareInSubFolder]);
+		$manager->method('generalCreateChecks')->willThrowException(new GenericShareException());
+
+		$this->defaultProvider->method('getSharesBy')
+			->willReturn([$reShare]);
+
+		$manager->expects($this->atLeast(2))->method('updateShare')->withConsecutive([$reShare], [$reShareInSubFolder]);
+
+		self::invokePrivate($manager, 'promoteReshares', [$share]);
+	}
+
+	public function testPromoteReshareWhenUserHasAnotherShare(): void {
+		$manager = $this->createManagerMock()
+			->setMethods(['updateShare', 'getSharesInFolder', 'getSharedWith', 'generalCreateChecks'])
+			->getMock();
+
+		$folder = $this->createMock(Folder::class);
+
+		$share = $this->createMock(IShare::class);
+		$share->method('getShareType')->willReturn(IShare::TYPE_USER);
+		$share->method('getNodeType')->willReturn('folder');
+		$share->method('getSharedWith')->willReturn('UserB');
+		$share->method('getNode')->willReturn($folder);
+
+		$reShare = $this->createMock(IShare::class);
+		$reShare->method('getShareType')->willReturn(IShare::TYPE_USER);
+		$reShare->method('getNodeType')->willReturn('folder');
+		$reShare->method('getSharedBy')->willReturn('UserB');
+		$reShare->method('getNode')->willReturn($folder);
+
+		$this->defaultProvider->method('getSharesBy')->willReturn([$reShare]);
+		$manager->method('getSharesInFolder')->willReturn([]);
+		$manager->method('generalCreateChecks')->willReturn(true);
+
+		$manager->expects($this->never())->method('updateShare');
+
+		self::invokePrivate($manager, 'promoteReshares', [$share]);
+	}
+
+	public function testPromoteReshareOfUsersInGroupShare(): void {
+		$manager = $this->createManagerMock()
+			->setMethods(['updateShare', 'getSharesInFolder', 'getSharedWith', 'generalCreateChecks'])
+			->getMock();
+
+		$folder = $this->createMock(Folder::class);
+
+		$userA = $this->createMock(IUser::class);
+		$userA->method('getUID')->willReturn('userA');
+
+		$share = $this->createMock(IShare::class);
+		$share->method('getShareType')->willReturn(IShare::TYPE_GROUP);
+		$share->method('getNodeType')->willReturn('folder');
+		$share->method('getSharedWith')->willReturn('Group');
+		$share->method('getNode')->willReturn($folder);
+		$share->method('getShareOwner')->willReturn($userA);
+
+		$reShare1 = $this->createMock(IShare::class);
+		$reShare1->method('getShareType')->willReturn(IShare::TYPE_USER);
+		$reShare1->method('getNodeType')->willReturn('folder');
+		$reShare1->method('getSharedBy')->willReturn('UserB');
+		$reShare1->method('getNode')->willReturn($folder);
+
+		$reShare2 = $this->createMock(IShare::class);
+		$reShare2->method('getShareType')->willReturn(IShare::TYPE_USER);
+		$reShare2->method('getNodeType')->willReturn('folder');
+		$reShare2->method('getSharedBy')->willReturn('UserC');
+		$reShare2->method('getNode')->willReturn($folder);
+
+		$userB = $this->createMock(IUser::class);
+		$userB->method('getUID')->willReturn('userB');
+		$userC = $this->createMock(IUser::class);
+		$userC->method('getUID')->willReturn('userC');
+		$group = $this->createMock(IGroup::class);
+		$group->method('getUsers')->willReturn([$userB, $userC]);
+		$this->groupManager->method('get')->with('Group')->willReturn($group);
+
+		$this->defaultProvider->method('getSharesBy')
+			->willReturn([]);
+		$manager->method('generalCreateChecks')->willThrowException(new GenericShareException());
+
+		$manager->method('getSharedWith')->willReturn([]);
+		$manager->expects($this->exactly(2))->method('getSharesInFolder')->willReturnOnConsecutiveCalls([[$reShare1]], [[$reShare2]]);
+
+		$manager->expects($this->exactly(2))->method('updateShare')->withConsecutive([$reShare1], [$reShare2]);
+
+		self::invokePrivate($manager, 'promoteReshares', [$share]);
+	}
+
 	public function testGetShareById(): void {
 		$share = $this->createMock(IShare::class);