Add cache for un-changed files

[TomasVotruba]

Depends on #3197

Enable in Config

# rector.yaml
parameters:
    is_cache_enabled: true # false by default

• add feature flag, disabled by default for testing

Without cache (~ 18 seconds on 200 files)

With cache (~ 1 second on 200 files)

Ref #3110

Notes

How to approach rules, that needs more scope for analysis, like:

• PrivatizeLocalOnlyMethodRector
• RemoveUnusedClassConstantRector

etc. Extend dependency files resolver? Probably best would be:

[ruudboon]

Nice work!

[ruudboon]

Lgtm

[bendavies]

phpstan and psalm both do dependency tracking for caching, which sounds like you want to do.

[TomasVotruba]

@bendavies This PR uses part of PHPStan dependency resolver. It works quite well.

Rector just sometimes needs full scope of the application, e.g. for unused public class method. For that I came up with interface that needs full cache clear. I wonder if that can be done in some better way. Ideas?

[Aerendir]

Wow, great work Tomas!

I will try to understand the implementation, but in those days it is really complex for me due to Covid limitations: I'm forced at home with my wife and my three years old son: it is really really complex to work...

[TomasVotruba]

@Aerendir Oh, I can't imagine how you're feeling while coding in this environment. I wish we all survive this in both physical and mental health. I sometime go for a run in the park or coding there. It helps me to lay of some steam from lockdown. Also hangouting or calling with friends. If you want one, we can do :)

Anyway, if you find something you don't understand, just go for it and write a comment. It's a first draft and I believe most of it can be written much better way. That's why appreciate feedback so much.

[TomasVotruba]

Let's 🚢 it!