MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/199305+s <!-- NOTE: For context on MR heading, see: https://handbook.gitlab.com/handbook/engineering/devops/dev/create/remote-development/index.html#relationship-of-issues-to-mrs --> ## Description ### Overview Add devfile validation to explicitly disallow usage of `mountSources` and `sourceMapping` until we support them. See [this comment](https://gitlab.com/gitlab-org/gitlab/-/issues/553096#note_2644681323) on https://gitlab.com/gitlab-org/gitlab/-/issues/553096+s for context. ### Details We don't seem to be handling at all the devfile standards for `mountSources` and `sourceMapping`. * https://devfile.io/docs/2.3.0/devfile-schema#components-container-mount-sources * https://devfile.io/docs/2.3.0/devfile-schema#components-container-source-mapping We should explicitly disable them in the devfile validation until we can add support for them. ## Acceptance criteria - [x] If `mountSources` or `sourceMapping` appears in a devfile, the validation should fail - [ ] User-facing documentation should be updated accordingly ## Implementation plan - These changes will be added to `ee/lib/remote_development/devfile_operations/restrictions_enforcer.rb` - Doc updates will be made in `doc/user/workspace/_index.md` <!-- NOTE: Feel free to expand with more sections and headers as needed --> <!-- DO NOT TOUCH BELOW -->