Silverstripe-framework: PHP 8 Compatibility across core

[Cheddam]

We've made a start on this with the merging in of support in silverstripe/framework, but need to expand this to the rest of the core modules. Our current target for shipping this compatibility is the CMS 4.7.0 release. PHP 8 support in CMS 3.x is out of scope, due to its limited support status.

Each module needs a CI matrix entry for PHP 8 (php: nightly), and will have to adopt the sminnee/phpunit fork for that build to pass. We've also been using these PRs to add a --prefer-lowest build for better coverage, and applying PHP compatibility to individual modules (7.1 || ^8.)

Tasks

recipe/core

• [x] Verified compatibility in silverstripe/assets - https://github.com/silverstripe/silverstripe-assets/pull/424
• [x] Verified compatibility in silverstripe/config - https://github.com/silverstripe/silverstripe-config/pull/46
• [x] Verified compatibility in silverstripe/framework - #9665
• [x] Verified compatibility in silverstripe/mimevalidator - https://github.com/silverstripe/silverstripe-mimevalidator/pull/42

recipe/cms

• [x] Verified compatibility in silverstripe/admin - https://github.com/silverstripe/silverstripe-admin/pull/1118
• [x] Verified compatibility in silverstripe/asset-admin - https://github.com/silverstripe/silverstripe-asset-admin/pull/1140
• [x] Verified compatibility in silverstripe/campaign-admin - https://github.com/silverstripe/silverstripe-campaign-admin/pull/179
• [x] Verified compatibility in silverstripe/cms - https://github.com/silverstripe/silverstripe-cms/pull/2595
• [x] Verified compatibility in silverstripe/errorpage - https://github.com/silverstripe/silverstripe-errorpage/pull/57
• [x] Verified compatibility in silverstripe/graphql - https://github.com/silverstripe/silverstripe-graphql/pull/302
• [x] Verified compatibility in silverstripe/reports - https://github.com/silverstripe/silverstripe-reports/pull/131
• [x] Verified compatibility in silverstripe/siteconfig - https://github.com/silverstripe/silverstripe-siteconfig/pull/115
• [x] Verified compatibility in silverstripe/versioned - https://github.com/silverstripe/silverstripe-versioned/pull/303
• [x] Verified compatibility in silverstripe/versioned-admin - https://github.com/silverstripe/silverstripe-versioned-admin/pull/179

Final steps

• [x] Verified compatibility in silverstripe/recipe-plugin (no CI or tests, needs smoke testing)
• [x] Verified compatibility in recipes
  
  
  
  • [x] silverstripe/recipe-core - https://github.com/silverstripe/recipe-core/pull/61
  
  
  • [x] silverstripe/recipe-cms - https://github.com/silverstripe/recipe-cms/pull/39
  
  
  • [x] silverstripe/installer - https://github.com/silverstripe/silverstripe-installer/pull/290
  
  
• [x] Official PHP support bumped to ^7.1 || ^8 in silverstripe/framework
• [x] (STRETCH GOAL) Run behat against PHP 8 build - see note below
• [x] Smoke test has been performed with silverstripe-installer

Behat on PHP8

• Not possible at this stage without forking the behat/behat module as it's not compatible with PHP8
• Did a write up here https://github.com/silverstripeltd/product-issues/issues/267
• Team agreed to stick with PHP7 for behat for now and reassess in 2021

[Cheddam]

All PHP 8 compatibility PRs have been merged (aside from a small fix to ClassInfo), and smoke testing went well, so I'm closing this out 🎉

[robbieaverill]

Nice work @Cheddam and everyone else involved!

[sminnee]

Whoo! I look forward to running a PHP8 prod stack in the near future :-)