Remove deprecated govuk-main-wrapper mixins

[NickColley]

What

Remove a deprecated feature: govuk-main-wrapper and govuk-main-wrapper--l mixins. Instead, people should replace this mixin with more direct references to the spacing mixins

Why

The govuk-main-wrapper and govuk-main-wrapper--l mixins were marked as deprecated in v3.0.0

We're not sure these are useful, so these will be removed in a future release, if you are using either of these please let us know.

Who needs to know about this

Developers, Tech Writer

Done when

• govuk-main-wrapper mixin has been removed
• govuk-main-wrapper--l mixin has been removed
• Does any existing documentation refer to these mixins?
• "Details of breaking change" section below completed to help with writing release notes

Details of breaking change

• which users are affected: anyone using the govuk-main-wrapper or govuk-main-wrapper--l mixins in their Sass
• the change that’s been made: we've removed the govuk-main-wrapper and govuk-main-wrapper--l Sass mixins
• changes users will have to make: if they're using these mixins, they need to remove them. They can replace them with direct calls to our spacing mixins
• impact of users not making those changes: if they're using these mixins and don't remove them, their Sass will start erroring because it won't be able to find the mixins anymore.

[NickColley]

Wonder if we should use @warn directives on these before 4.0.0 @36degrees ?

[EoinShaughnessy]

Will we need to update the spacing mixins guidance? Or just tell users in the release notes?

[vanitabarrett]

Thanks @EoinShaughnessy , good shout. I don't think the spacing mixins guidance needs updating, but it looks like we do reference these mixins in https://design-system.service.gov.uk/styles/layout/#page-wrappers

[vanitabarrett]

@EoinShaughnessy Having had another look at the design system, I don't think any guidance on there needs updating as we only refer to the govuk-main-wrapper and govuk-main-wrapper--l classes which will continue to exist after this change has been made. We are only removing the mixins.

The Frontend Docs does reference these mixins, but that should automatically update once we release v4.0.0 and update the frontend docs repo to use that version.

[EoinShaughnessy]

@vanitabarrett Ah great, thanks - good to know!