Support onlyoffice connector >= 10.1 and fix PHP 8.4 nullable deprecations

[NSO73]

What

Two fixes that let documentserver_community run with the current ONLYOFFICE connector on recent PHP / Nextcloud.

1. Support ONLYOFFICE connector >= 10.1 (AppConfig constructor change)

The onlyoffice connector 10.1 changed OCA\Onlyoffice\AppConfig::__construct from

(string $appName, IConfig, LoggerInterface, ICacheFactory)            // <= 10.0

to

(string $appName, IAppConfig, IConfig, IUserConfig, LoggerInterface, ICacheFactory)   // >= 10.1

With the old 4-argument call the app no longer boots:

TypeError: OCA\Onlyoffice\AppConfig::__construct(): Argument #2 ($appConfig)
must be of type OCP\IAppConfig, OC\AllConfig given

buildAppConfig() now detects the constructor arity at runtime and passes the
matching arguments, so it keeps working with both the old (<= 10.0) and the new
(>= 10.1) connector — and the Nextcloud versions that ship them (OCP\Config\IUserConfig
only exists on the newer ones).

2. PHP 8.4 — explicit nullable parameter types

PHP 8.4 deprecates implicitly nullable parameters (Type $x = null). Made the
nullable explicit (?Type) for the $password parameters in DocumentConverter,
ConverterBinary and DocumentStore. No behaviour change; removes the deprecation
warnings logged on every document conversion.

Testing

Verified on Nextcloud 33.0.5 / PHP 8.4 with onlyoffice connector 10.1.0: the app
boots, /healthcheck returns 200, documents open and convert.

[audioanton]

I have this exact issue too. The PR looks like a sensible fix.

[sjs6776]

Note the fix on line 96 of my file below, this allows docserver to work on NC34.
Credit to @defame-flagstick for the code to fix getConfig() being deprecated
Application.php

[NSO73]

Thanks @sjs6776 (and @defame-flagstick) — I've folded the getConfig() fix into the PR (commit c230ddf): \OC::$server->getConfig() → \OC::$server->get(\OCP\IConfig::class), so it now also covers NC34.

Heads-up: I've since migrated to a native EuroOffice setup, so I won't be actively testing/maintaining this on my side anymore. I'm leaving the PR open in case it's useful to others and a maintainer wants to pick it up.

[blueforce]

This PR is also required for Nextcloud 34, not only for connector >= 10.1 — that might be worth reflecting in the title, since it's easy to miss.

On NC 34, OC\Server::getConfig() no longer exists. The two new AppConfig('onlyoffice', \OC::$server->getConfig(), ...) calls in Application.php therefore make the app fail to boot on every request:

Could not boot documentserver_community: Call to undefined method OC\Server::getConfig()

The visible result is HTTP 500 on /apps/documentserver_community/healthcheck, and the admin page shows "Error when trying to connect". Once that is fixed, the 6-parameter AppConfig constructor in connector 10.1.2 is the next blocker — which is exactly what buildAppConfig() here handles.

I ran into both on a production instance:

• Nextcloud 34.0.1
• PHP 8.3.31
• onlyoffice connector 10.1.2
• documentserver_community 0.2.4

To confirm the diagnosis I applied the equivalent change by hand (\OC::$server->get(\OCP\IConfig::class) plus the 6-argument constructor), not this exact branch. With that in place the app boots cleanly, /healthcheck returns true, and the boot errors disappear from the log. So I can confirm the root cause and that the fix direction is correct — but to be precise about scope: I have not run this branch verbatim, and I have not done a full editor regression test on NC 34.

One gap this PR doesn't cover: appinfo/info.xml still declares max-version="33", so even after this is merged the app won't be offered on NC 34 without a version bump.

[blueforce]

Update: I've now verified the editor itself on the same instance (Nextcloud 34.0.1, PHP 8.3.31, onlyoffice connector 10.1.2) — opening and editing .docx and .xlsx works cleanly, no errors in the log. The earlier caveat about the editor being untested no longer applies.

Still accurate: I'm running the equivalent fix applied by hand, not this branch verbatim.