Problem/Motivation
When the core_version_requirement line was added to Drupal core it immediately caused thousands of Drupal 8 modules and themes to no longer be compatible with core. While community effort has gone a good way towards making all modules and themes compatible, there are still thousands of them which have not been made compatible yet. Multiple projects (#3168047, #3227031) have looked at automating the process of making D8 projects compatible with D9, but even with that there would still be a sizable effort required by the community to manage the projects. There might be a better way of handling the total volume of work required of the community to make these under/un-maintained projects compatible with Drupal 9.
Related to this we would need a separate change to the Composer facade which would make the default composer.json generated for modules to declare compatibility with both Drupal 8 and 9 instead of just 8, allowing all modules to be added to a Drupal 9 codebase if either a composer.json file is not present that declares a core requirement, or the info.yml file(s) do not declare a core_version_requirement line.
Proposed resolution
Ignore the "core" attribute from info.yml files completely, including when running tests.
Change how the core_version_requirement setting in info.yml files is interpretted:
- If the core_version_requirement line is not present in a project, assume it is compatible with the current core version.
- If the core_version_requirement line is present in a project, process it as normal.
Remaining tasks
Reach agreement on the proposed plan.
Build the necessary changes.
User interface changes
TBD
API changes
TBD
Data model changes
TBD
Release notes snippet
TBD