Don't use mode="merge" in filter.xml

[ericvangeem]

Expected Behaviour

Any rules in the filter.xml files using mode="merge" should instead be using mode="merge_properties". Per Jackrabbit FileVault's documentation, the merge property is deprecated in favor of merge_properties as merge is "not handled consistently".

Actual Behaviour

Currently, the generated filter.xml files are using mode="merge"

Reproduce Scenario (including but not limited to)

Create a new AEM project from aem-project-archetype, observe various rules in filter.xml (most notably in ui.content) are using mode="merge"

We have observed severe content/data loss in an AEM 6.5+ environment as a result of using this merge property that comes with the aem-project-archetype. Specifically during the scenario where we have been continuously deploying a 1.0.0-SNAPSHOT maven version of our codebase (all bundles have same version including ui.content bundle), then once we deployed a maven release version of the codebase (1.0.0), Jackrabbit FileVault reverted a significant amount of content in the production environment resulting in large content loss. It is believed that the existence of mode="merge"within our ui.content/filter.xml for the common content paths such as /conf/mysite and /content/mysite caused these paths to be impacted in the production instance upon bundle installation.

Platform and Version

AEM 6.5+ & AEMaaCS

Sample Code that illustrates the problem

https://github.com/adobe/aem-project-archetype/blob/develop/src/main/archetype/ui.content/src/main/content/META-INF/vault/filter.xml