Add note about default values as parameters in Configuration component

[Koc]

More information here symfony/symfony#9558

[wouterj]

I'm not sure where to put this, as we don't have config articles in the framework docs (only in the component docs)

[xabbuh]

We could add it to one or more of the cookbook articles.

[stof]

@wouterj I would say in the cookbook article about providing semantic config for bundles. What do you think ?

[wouterj]

Ok, I think we should create a new cookbook article in cookbook/configuration which explains people:

• What the %...% syntax actually does (getting service parameter values, linking to the service book article)
• Where you can use that syntax (config, routing, service config, and maybe more?)
• How to handle that in the Configuration class (see issue [Configuration] Default value from parameter for BooleanNode works incorrectly symfony#9558 )

Then a couple articles should link to it:

• /cookbook/bundles/extension
• /cookbook/routing/service_container_parameters

[cordoval]

please add a hasPR label

[wouterj]

@cordoval the hasPR label is only used in preperation of a hackday.

[cordoval]

thought we were preparing for one 👍 when do you think we can make one?