EZP-30689: Registered Query Types for automatic configuration

[alongosz]

Question	Answer
JIRA issue	EZP-30689
Required by	#2651
Bug/Improvement	yes
New feature	no
Target version	master (8.0@dev) for eZ Platform v3.0
BC breaks	yes
Tests pass	yes
Doc needed	yes

This PR both provides an improvement and fixes broken behat test for Query Types by providing automatic configuration for them (autoconfigure: true causing auto-tagging of the services which implement \eZ\Publish\Core\QueryType\QueryType with ezpublish.query_type).

The reason for doing it now is unblocking Travis for #2651 to proceed with QA.

Breaking changes

Traversing through bundles to automatically register Query Types by the naming convention <Bundle>\QueryType\*QueryType has been dropped.

This convention imposed on a Developer specific directory structure, which is Symfony 2 mindset. Instead we provided automatic configuration for all services which implement QueryType interface.
It might seem like an additional setup step, but in fact, when we look at the services.yaml shipped with Symfony 4, we can see that the entire src directory has been mapped to App\* services with auto-configuration. It means that just placing that class in developer-chosen "autoconfigured" namespace is enough. It yields the same DX as it used to, without 50 lines of our code.

Doc

If the changes are accepted, the section "By convention" needs to be dropped or rephrased. The replacement convention now is auto-configuring service. The following section "Using a service tag" needs to be adjusted.
DIC config examples:

Recommended:

    App\Query\LatestContent:
        autoconfigure: true

By Service Tag:

    App\Query\LatestContent:
        tags:
            - {name: ezpublish.query_type}

By explicit alias instead of name (might be required in the future, if your QueryType needs to be lazy):

    App\Query\LatestContent:
        tags:
            - { name: ezpublish.query_type, alias: LatestContent }

TODO:

• Register instances of \eZ\Publish\Core\QueryType\QueryType for auto-configuration.
• Drop traversing through bundles to find Query Types (in favor of ^ auto-conf).
• Implement DI tests.
• Extract ezpublish.query_type" to a constant.
• Fix Behat Query Types Feature scenario.
• See if Behat test passes.
• Fix new code according to Coding Standards ($ composer fix-cs).
• Ask for Code Review.

[bdunogier]

As long as the developer experience is the same in the end, I'm fine with the change.

[alongosz]

As long as the developer experience is the same in the end, I'm fine with the change.

For e.g. Demo no change is required, which proves my point :)
Because in Sf4 all services are by default autoconfigured (the whole App\ namespace is mapped), I'd say experience is exactly the same. Unless someone has different setup, but we have no control over that (the same way we didn't have control over where developers have put their QueryTypes classes anyway).

[bdunogier]

There is one thing that breaks: if you define query types in bundles other than App. Such as bundles an integrator would reuse over projects. Do we have ways to warn in 2.x that relying on the path alone is deprecated ?

[alongosz]

There is one thing that breaks: if you define query types in bundles other than App. Such as bundles an integrator would reuse over projects.

Properly written bundle should register those as services anyway, but...

Do we have ways to warn in 2.x that relying on the path alone is deprecated ?

We could add that, reported it already as a bug (EZP-31064) because this PR is going to be merged in a moment to unblock QA on #2651.

[alongosz]

QA will be done on #2651.

[bdunogier]

Properly written bundle should register those as services anyway, but...
Yes, "but.."
We did provide an alternative way to do so. Maybe it wasn't a smart move, but it was official. So maybe we can at least warn users upfront that they should modify their configuration and add autoconfigure to their querytypes ?

[alongosz]

Yes, therefore added EZP-31064.