Upgrading to Scala 2.13

[rtyley]

Base assumption: Project is already on Scala 2.12

Examples

• Media Atom Maker PRs, concluding Upgrade to Scala v2.13 media-atom-maker#1147
• MAPI PRs, concluding https://github.com/guardian/mobile-apps-api/pull/2654
• Ophan PRs, concluding https://github.com/guardian/ophan/pull/3658

Useful resources

• Scalafix
• rtyley/scala-collection-plus - handle Scala 2.13's deprecation of .mapValues() with .mapV()

Dependency support for Scala 2.13

In most cases you should be able to use the Scaladex to find the minimum version needed, eg, for content-api-client. Also look for the Scaladex badge on the project ReadMe, it should tell you everything you need to know, eg:

Minimum library versions

• Editorial permissions library 2.7
  • Upgrade Editorial permissions library to latest version media-atom-maker#1142
• pan-domain-authentication 1.0.4
• Scanamo 1.0.0-M11
  • Upgrading to Scanamo v1 #6

Libraries without support

• play-iteratees
  • https://github.com/guardian/mobile-apps-api/pull/2595
  • Remove play-iteratees frontend#25176
  • https://github.com/guardian/presence-indicator/pull/186
• bizzabo/diff ("ai.x" %% "diff")
  • Drop unmaintained diff library for logging MediaAtom changes media-atom-maker#1141
• bizzabo/play-json-extensions ("ai.x" %% "play-json-extensions")
  • Note, this can be replaced, if necessary, with guardian/play-json-extensions ("com.gu" %% "play-json-extensions")