Fix MemoryCache discovery and DX

One small comment on the MR but overall looks like a good improvement to me.

What about using 'memory' instead of 'static' in the various places this is wired up. There's potential confusion with APCu or even memcache, but less confusion with PHP statics.

Did a quick look to the best of my ability with caching.

Believe we may have to do the backward compatibility dance now right?

Also may need a change record for the new parameter.

Not sure if there is concern for contrib that could be using Drupal\Core\Cache\MemoryCache\MemoryCache and not the interface?

Thanks for following up on my thread.

So don't need a change record for the new parameter but imagine for the new MemoryCacheFactory? For other contrib modules can take advantage.

CR reads well.

In regards to the book rename, think you can open a ticket for the book module and put into postponed. Then when book is deprecated that ticket will be brought over.

I'm interpreting catch's latest comment on the MR as if we should add the typehint here as it's new code

Yes sorry that's what I meant - even though it's inconsistent within the class, it is much easier to add when it's new, than trying to add retrospectively, which we are only just figuring out how to do at all.

I found one more small issue in the MR (which I was planning to commit until I spotted it) - I think it is just removing that part of the comment so should be straightforward to resolve - nearly did it on commit but wasn't sure exactly the best place to snip it from.

Yes I think that's good!

Committed/pushed to 11.x (which is also still 10.3.x at the moment), thanks!

I'm a bit confused by this change.

  # Cache.
  cache.jsonapi_memory:
    class: Drupal\Core\Cache\MemoryCache\MemoryCacheInterface
    tags:
      - { name: cache.bin.memory, default_backend: cache.backend.memory.memory }
    factory: ['@cache_factory', 'get']
    arguments: [jsonapi_memory]

  cache.jsonapi_resource_types:
    class: Drupal\Core\Cache\BackendChain
    calls:
      - [appendBackend, ['@cache.jsonapi_memory']]
      - [appendBackend, ['@cache.default']]
    tags: [{ name: cache.bin.memory }]

BackendChain passes cache tag invalidations through to the inner bins. That means any cache tag invalidations are now processed twice by cache.jsonapi_memory.

I can see that \Drupal\Core\Test\RefreshVariablesTrait::refreshVariables() calls a special reset() method that is not on the interface and only some memory implementations have that, but couldn't we have "just" implemented that on BackendChain and pass it through as well?

This made cache.jsonapi_memory public but that feels wrong to me as it never should be used directly, only through the chain?