Unable to publish/preview new assets when quick publish from tools config page editor

[srikanthgurram-17]

This is to solve the issue wcm-io/io.wcm.caconfig.editor#47.

• Right now the ConfigurationReferenceProvider is called when we try to publish the page using tools --> config page
• The ConfigurationReferenceProvider class is responsible to identify all the ca config references in a page
• In future we need to support all the assets type referenced in ca config as well as ca config type reference we need to provide asset references which are outdated or newly added.
• I have updated this class so that it finds both types.

[srikanthgurram-17]

@stefanseifert Can you review this MR please?

[srikanthgurram-17]

@stefanseifert gentle reminder, As I am away after this Friday until next year to do any changes.

[stefanseifert]

thanks for the contribution!

there are some sonar findings (which unfortunately are not visible for external PRs directly in the PR comments), please have a look at https://sonarcloud.io/summary/new_code?id=wcm-io_io.wcm.caconfig.extensions&branch=feature%2Fassetreferences-publishing-support

overall this is the right approach, but there are some open issues.

[stefanseifert]

i've refactored the code to cover more edge cases:

• detect asset references in configuration collections and nested configurations (stored as nested resources)
• detect asset references not only in string properties, but also in string array properties
• de-duplicate list of collected assets in case the same asset is references multiple times

i also moved the actual reference detection logic to a separate class to not clutter the main class too much, and make the edge cases testable independent of the other (complex) parts of the reference provider.

additionally, i added a new OSGi configuration option which allows to enable the detection of asset, but is disabled by default. so, we can test it a bit if it has performance impact, before enable it for everyone maybe in a later release.