Refactor lib/private

[shdehnavi]

Summary

The required adjustments have been made to the following classes under /lib/private namespace:

• PreviewManager.php
• Repair.php
• RedisFactory.php
• Search.php
• Server.php
• ServerContainer.php

The improvements:

• Using PHP8's constructor property promotion
• Adding return types
• Adding types to properties
• Updating doc blocks
• Converting if (isset(...)) to null coalescing operator

Checklist

• Code is properly formatted
• Sign-off message is added to all commits

[fsamapoor]

Could you please resolve the conflicts?

[come-nc]

Suggested change

	protected function getEnabledDefaultProvider(): ?array {
	protected function getEnabledDefaultProvider(): array {

I do not see where it returns null?
Docblock @return should be reverted to array as well or removed.

[come-nc]

This cannot work because the property is not instanciated in constructor.
Most likely should be changed to:

Suggested change

	private \Redis|\RedisCluster $instance;
	private \Redis|\RedisCluster|null $instance;

And then the class should be adapted so that psalm is happy. The create method is used for creating the object.
The instanceof test in getInstance looks wrong as it does not test cluster.

[come-nc]

Not sure it makes sense to strong type these obsolete methods.

[nickvergessen]

deprecated since 20 means we can even remove it when not actively used in shipped apps or server :P

[come-nc]

Suggested change

	public function getBruteForceThrottler(): Throttler {
	public function getBruteForceThrottler(): IThrottler {