fix(user_status): make setUserStatus() idempotent for concurrent duplicate requests

When two automated events of the same type fire simultaneously (e.g. a
calendar webhook is delivered twice, or two Talk clients both trigger a
call status at the same time), both requests race through setUserStatus().

The first request succeeds: it creates a backup of the user's previous
status and sets the new automated status. The second request finds the
backup slot already occupied (unique constraint on user_id), so
backupCurrentStatus() returns false. Previously this caused setUserStatus()
to return null, which the caller interpreted as a failure even though the
desired status was already correctly set by the first request.

Fix: after backupCurrentStatus() returns false, re-read the current active
status row. If it already carries the same messageId that we were trying to
set, the operation is effectively complete — return the existing status
instead of null. If it carries a different messageId (a higher-priority
automated status is active), we still return null to abort as before.

This also covers the meeting-with-call scenario: if a calendar BUSY status
is active and a Talk call starts, the call correctly overrides it via the
priority shortcut path. If the calendar fires a duplicate webhook while the
call is already active, the re-read finds MESSAGE_CALL ≠ MESSAGE_CALENDAR_BUSY
and correctly aborts rather than overriding the ongoing call.

AI-Assisted-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Anna Larch <anna@nextcloud.com>

Author: miaulalala

apps/user_status/lib/Service/StatusService.php

@@ -284,7 +284,18 @@ public function setUserStatus(string $userId,
 
 		if ($createBackup) {
 			if ($this->backupCurrentStatus($userId) === false) {
-				return null; // Already a status set automatically => abort.
+				// A backup already exists, meaning another automated status is active.
+				// If the active status already carries the same messageId, this is a
+				// duplicate/concurrent request for the same event — treat it as success.
+				try {
+					$currentStatus = $this->mapper->findByUserId($userId);
+					if ($currentStatus->getMessageId() === $messageId) {
+						return $currentStatus;
+					}
+				} catch (DoesNotExistException) {
+					// No active status row exists, fall through to abort
+				}
+				return null; // A different automated status is active => abort.
 			}
 
 			// If we just created the backup

apps/user_status/tests/Unit/Service/StatusServiceTest.php

@@ -802,7 +802,7 @@ public function testSetUserStatus(string $messageId, string $oldMessageId, bool
 		$previous->setUserId('john');
 		$previous->setIsBackup(false);
 
-		$this->mapper->expects($this->once())
+		$this->mapper->expects($this->exactly($expectedUpdateShortcut ? 1 : 2))
 			->method('findByUserId')
 			->with('john')
 			->willReturn($previous);
@@ -825,4 +825,36 @@ public function testSetUserStatus(string $messageId, string $oldMessageId, bool
 
 		$this->service->setUserStatus('john', IUserStatus::DND, $messageId, true);
 	}
+
+	public function testSetUserStatusIdempotentOnConcurrentDuplicateRequest(): void {
+		$existing = new UserStatus();
+		$existing->setId(1);
+		$existing->setStatus(IUserStatus::DND);
+		$existing->setStatusTimestamp(1337);
+		$existing->setIsUserDefined(true);
+		$existing->setMessageId(IUserStatus::MESSAGE_CALL);
+		$existing->setUserId('john');
+		$existing->setIsBackup(false);
+
+		$this->mapper->expects($this->exactly(2))
+			->method('findByUserId')
+			->with('john')
+			->willReturn($existing);
+
+		/** @var MockObject&Exception $exception */
+		$exception = $this->createMock(Exception::class);
+		$exception->method('getReason')->willReturn(Exception::REASON_UNIQUE_CONSTRAINT_VIOLATION);
+		$this->mapper->expects($this->once())
+			->method('createBackupStatus')
+			->willThrowException($exception);
+
+		$this->predefinedStatusService->expects($this->once())
+			->method('isValidId')
+			->with(IUserStatus::MESSAGE_CALL)
+			->willReturn(true);
+
+		// Active status already has MESSAGE_CALL — concurrent duplicate request should succeed
+		$result = $this->service->setUserStatus('john', IUserStatus::DND, IUserStatus::MESSAGE_CALL, true);
+		$this->assertSame($existing, $result);
+	}
 }