[DependencyInjection] Add documentation for service locator changes

[codedmonkey]

Adds documentation for PR symfony/symfony#28571

[codedmonkey]

Code has been merged :)

[javiereguiluz]

@codedmonkey for this kind of features, we always add some comments and examples in the code samples, to make it easier to understand. Could you please my reword to do that? Thanks!

[javiereguiluz]

@codedmonkey the current YAML example that I added is wrong:

# config/services.yaml
services:
    app.command_handler_locator:
        class: Symfony\Component\DependencyInjection\ServiceLocator
        arguments:
           -
               App\FooCommand: '@app.command_handler.foo'
               App\BarCommand: '@app.command_handler.bar'
               # if the element has no key, the ID of the original service is used
               '@app.command_handler.baz'

It says:

(<unknown>): could not find expected ':' while scanning a simple key
at line 10 column 16

What's the correct syntax for YAML? Or maybe this feature is not supported in YAML? Thanks!

[javiereguiluz]

Anyone knows if this feature works with YAML config? @xabbuh? @nicolas-grekas? If it works, which is the syntax? Thanks!

[codedmonkey]

My apologies for the late response.

It looks like combining collections aand arrays in YAML is indeed a no-go, symfony/symfony#23664. It's possible to do either

        arguments:
           -
               - '@app.command_handler.foo'
               - '@app.command_handler.bar'
               - '@app.command_handler.baz'

or

        arguments:
           -
               App\FooCommand: '@app.command_handler.foo'
               App\BarCommand: '@app.command_handler.bar'
               App\BazCommand: '@app.command_handler.baz'

but not a combination of the two. Trying to add the feature would just increase complexity. Any ideas how best to address this in the docs?

[xabbuh]

That's correct, a collection in YAML is either a sequence or a mapping. I would just add a second example like this:

# config/services.yaml
services:
    app.command_handler_locator:
        class: Symfony\Component\DependencyInjection\ServiceLocator
        arguments:
           -
               App\FooCommand: '@app.command_handler.foo'
               App\BarCommand: '@app.command_handler.bar'

    # or if the element has no key, the ID of the original service is used
    app.another_command_handler_locator:
        class: Symfony\Component\DependencyInjection\ServiceLocator
        arguments:
           -
               - '@app.command_handler.baz'

[OskarStark]

Please add a blank line after the directive

[javiereguiluz]

It took us forever ... but this is finally merged. Thank you all for your help and contributions.