Deprecate facade magic for removal with D13
Migrated issue
Reported by: cmlara
Problem/Motivation
The composer facade for packages.drupal.org currently performs backend 'magic' of interpreting various files including the info.yml and adding records into the composer metadata for a published package.
This feature was very useful when composer was just being deployed and the ecosystem needed to add support to all modules without any maintainer interaction.
Recently, as has happened in the past, we have begun to see core modules that have been moved to contrib change composer dependencies (as the facade recalculates dependencies) and break existing supported deployments.
I propose that for any module that supports D13 (in info.yml or composer.json) that the facade cease making any change to existing composer.json files and require that modules must have a composer.json.
We already require for any module with dependencies a composer.json be added to allow GitLabCI to function. This has not been a significant burden for maintainers. This would just extend the requirement to all modules including those without dependencies.
D13 chosen as some modules have already released claims to D12 support.
Steps to reproduce
composer show -a drupal/s3fs 3.10.0
Observe that core requirements have been added even though the composer.json in the repository fails to include them.
Proposed resolution
For any module that supports D13 or newer render the composer.json exactly as included in the repository.
Optionally: Fail the build (or at least warn before building) if the composer.json does not include a drupal/core requirement.