Feature: #107837 - Route enhancers in site sets

Description

Site sets can now define route enhancers in a dedicated route-enhancers.yaml file. This allows extensions to provide route enhancers as part of their site set configuration, which are automatically merged into the site configuration when the set is used as a dependency.

The route enhancers from site sets are applied as presets. This means that site-level route enhancer configuration takes precedence and can override set-defined enhancers.

Usage

Create a route-enhancers.yaml file in your site set directory alongside the config.yaml:

EXT:my_extension/Configuration/Sets/MySet/
├── config.yaml
└── route-enhancers.yaml

The file must contain a routeEnhancers key with the route enhancer definitions:

EXT:my_extension/Configuration/Sets/MySet/route-enhancers.yaml

routeEnhancers:
  MyEnhancer:
    type: Simple
    routePath: '/my-path/{param}'
    aspects:
      param:
        type: StaticValueMapper
        map:
          value1: '1'
          value2: '2'

The route enhancers file supports YAML imports, allowing you to split configuration across multiple files:

EXT:my_extension/Configuration/Sets/MySet/route-enhancers.yaml

imports:
  - { resource: 'route-enhancers/*.yaml' }

routeEnhancers:
  # Additional enhancers can be defined here

Merging behavior

Route enhancers from site sets are merged in dependency order. When a site uses multiple sets, enhancers from earlier dependencies are loaded first, and later sets can override them.

Site-level route enhancer configuration always takes precedence over set-defined enhancers. This allows sites to customize or override preset configurations from sets.

Example

Given a site set with:

EXT:my_extension/Configuration/Sets/MySet/route-enhancers.yaml

routeEnhancers:
  PageType:
    type: PageType
    default: '0'
    map:
      feed.xml: '100'

And a site configuration with:

config/sites/my-site/config.yaml

dependencies:
  - my_extension/my-set

routeEnhancers:
  PageType:
    type: PageType
    default: '100'
    map:
      rss.xml: '200'

The resulting configuration will be:

routeEnhancers:
  PageType:
    type: PageType
    default: '100'
    map:
      feed.xml: '100'
      rss.xml: '200'

Scalar values from the site configuration override set-defined values, while new keys are appended.

Impact

Extensions can now ship route enhancers as part of their site sets, providing a streamlined way to configure routing for extension functionality. This is particularly useful for extensions that require specific URL patterns, such as sitemap extensions or API endpoints.

Invalid route enhancer configurations are handled gracefully: sets with invalid route-enhancers.yaml files are skipped and logged, similar to other set validation errors.