`occ user:sync-account-data` without function

[SystemKeeper]

• Noticed while working on fix: Make User_Proxy IGetDisplayNameBackend complient #57452

The command occ user:sync-account-data currently updates the displayname, when the backend implements IGetDisplayNameBackend:

server/core/Command/User/SyncAccountDataCommand.php

Lines 58 to 75 in d341c20

	if ($user->getBackend() instanceof IGetDisplayNameBackend) {
	try {
	$displayNameProperty = $account->getProperty(IAccountManager::PROPERTY_DISPLAYNAME);
	} catch (PropertyDoesNotExistException) {
	$displayNameProperty = null;
	}
	if (!$displayNameProperty || $displayNameProperty->getValue() !== $user->getDisplayName()) {
	$output->writeln($user->getUID() . ' - updating changed display name');
	$account->setProperty(
	IAccountManager::PROPERTY_DISPLAYNAME,
	$user->getDisplayName(),
	$displayNameProperty ? $displayNameProperty->getScope() : IAccountManager::SCOPE_PRIVATE,
	$displayNameProperty ? $displayNameProperty->getVerified() : IAccountManager::NOT_VERIFIED,
	$displayNameProperty ? $displayNameProperty->getVerificationData() : ''
	);
	$changed = true;
	}
	}

But the account data that is used to compare the displayname, always return the up-to-date displayname:

server/lib/private/Accounts/AccountManager.php

Lines 664 to 667 in d341c20

	if ($user->getBackend() instanceof IGetDisplayNameBackend) {
	$property = $account->getProperty(self::PROPERTY_DISPLAYNAME);
	$account->setProperty(self::PROPERTY_DISPLAYNAME, $user->getDisplayName(), $property->getScope(), $property->getVerified());
	}

(implemented at #39770)

So if I am not mistaken, occ user:sync-account-data is basically a NOP?

CC @juliusknorr as creator of the occ command.