As release engineering I want the correct versions of libraries to be running in production as required by deployed extensions in order to ensure the stability of the product.
As a developer I want to be able to use the newer features provided by version 4.0.0 in order to continue cleanup and development.

Details

List of dependants can be found at https://packagist.org/packages/serialization/serialization/dependents
The release notes for 4.0.0 can be found at https://github.com/wmde/Serialization/releases/tag/4.0.0

As of 18/08/2018 the components that need to be updated are as follows:

• composer library: data-values/serialization (version 1.2.2 can be installed with 4.0)
• composer library: wikibase/data-model-serialization (version 2.8.0 can be installed with 4.0)
• composer library: wikibase/internal-serialization (version 2.8.0 can be installed with 4.0)
• extension: WikibaseLexeme
• extension: WikibaseMediaInfo
• extension: WikibaseQuality
• extension: WikibaseQualityConstraints
• wmf: mediawiki-vendor

Note: Since april WMF production has actually already been running with version 4.0.0 despite the extensions not specifying that they are compatible with it.. See:

• https://gerrit.wikimedia.org/r/#/c/mediawiki/vendor/+/423736/ (already merged patches making mediawiki-vendor use 4.0.0)
• https://gerrit.wikimedia.org/r/#/c/mediawiki/vendor/+/453581/ (reverting it back to 3.2.2 which is allowed per the various specified requirements)

The cleanup of what is currently deployed should probably be merged first...
The extensions should be updated first and all patches merged before the patch for mediawiki-vendor is merged.

Impact & priority

Currently there does not seem to be any development blocked on using the new version so this would be a low priority until such a task that is blocked by this appears.
On the flip side out deployment of this library is currently a bit out of whack and in production we are currently already running with version 4.0.0 despite our extensions not specifying that they allow it, we should clean this up otherwise it might cause us some unexpected surprise.

Task

Convert all listed extensions to be installable using serialization/serialization 4.0.0.

Acceptance criteria

• All listed components can be installed with serialization/serialization ~4.0|~3.0
• The wmf mediawiki-vendor directory has been updated to load serialization/serialization 4.0.0
• All extensions should have their patches merged before updating mediawiki-vendor