gitlab-org--gitlab-foss/doc/development/limit_ee_conflicts.md

Limit conflicts with EE when developing on CE

This guide contains best-practices for avoiding conflicts between CE and EE.

Context

Usually, GitLab Community Edition is merged into the Enterprise Edition once a week. During these merges, it's very common to get conflicts when some changes in CE do not apply cleanly to EE.

There are a few things that can help you as a developer to:

• know when your merge request to CE will conflict when merged to EE
• avoid such conflicts in the first place
• ease future conflict resolutions if conflict is inevitable

Check the rake ee_compat_check in your merge requests

For each commit (except on master), the rake ee_compat_check CI job tries to detect if the current branch's changes will conflict during the CE->EE merge.

The job reports what files are conflicting and how to setup a merge request against EE. Here is roughly how it works:

1. Generates the diff between your branch and current CE master
2. Tries to apply it to current EE master
3. If it applies cleanly, the job succeeds, otherwise...
4. Detects a branch with the -ee suffix in EE
5. If it exists, generate the diff between this branch and current EE master
6. Tries to apply it to current EE master
7. If it applies cleanly, the job succeeds

In the case where the job fails, it means you should create a <ce_branch>-ee branch, push it to EE and open a merge request against EE master. At this point if you retry the failing job in your CE merge request, it should now pass.

Notes:

• This task is not a silver-bullet, its current goal is to bring awareness to developers that their work needs to be ported to EE.
• Community contributors shouldn't submit merge requests against EE, but reviewers should take actions by either creating such EE merge request or asking a GitLab developer to do it once the merge request is merged.
• If you branch is more than 500 commits behind master, the job will fail and you should rebase your branch upon latest master.

Possible type of conflicts

Controllers

List or arrays are augmented in EE

In controllers, the most common type of conflict is with before_action that has a list of actions in CE but EE adds some actions to that list.

The same problem often occurs for params.require / params.permit calls.

Mitigations

Separate CE and EE actions/keywords. For instance for params.require in ProjectsController:

def project_params
  params.require(:project).permit(project_params_ce)
  # On EE, this is always:
  # params.require(:project).permit(project_params_ce << project_params_ee)
end

# Always returns an array of symbols, created however best fits the use case.
# It _should_ be sorted alphabetically.
def project_params_ce
  %i[
    description
    name
    path
  ]
end

# (On EE)
def project_params_ee
  %i[
    approvals_before_merge
    approver_group_ids
    approver_ids
    ...
  ]
end

Additional condition(s) in EE

For instance for LDAP:

    def destroy
      @key = current_user.keys.find(params[:id])
 -    @key.destroy
 +    @key.destroy unless @key.is_a? LDAPKey

      respond_to do |format|

Or for Geo:

def after_sign_out_path_for(resource)
-    current_application_settings.after_sign_out_path.presence || new_user_session_path
+    if Gitlab::Geo.secondary?
+      Gitlab::Geo.primary_node.oauth_logout_url(@geo_logout_state)
+    else
+      current_application_settings.after_sign_out_path.presence || new_user_session_path
+    end
end

Or even for audit log:

def approve_access_request
-    Members::ApproveAccessRequestService.new(membershipable, current_user, params).execute
+    member = Members::ApproveAccessRequestService.new(membershipable, current_user, params).execute
+
+    log_audit_event(member, action: :create)

  redirect_to polymorphic_url([membershipable, :members])
end

Views

Additional view code in EE

A block of code added in CE conflicts because there is already another block at the same place in EE

Mitigations

Blocks of code that are EE-specific should be moved to partials as much as possible to avoid conflicts with big chunks of HAML code that that are not fun to resolve when you add the indentation to the equation.

For instance this kind of thing:

- if can?(current_user, :"admin_#{issuable.to_ability_name}", issuable.project)
  - has_due_date = issuable.has_attribute?(:due_date)
  %hr
  .row
    %div{ class: (has_due_date ? "col-lg-6" : "col-sm-12") }
      .form-group.issue-assignee
        = f.label :assignee_id, "Assignee", class: "control-label #{"col-lg-4" if has_due_date}"
        .col-sm-10{ class: ("col-lg-8" if has_due_date) }
          .issuable-form-select-holder
            - if issuable.assignee_id
              = f.hidden_field :assignee_id
            = dropdown_tag(user_dropdown_label(issuable.assignee_id, "Assignee"), options: { toggle_class: "js-dropdown-keep-input js-user-search js-issuable-form-dropdown js-assignee-search", title: "Select assignee", filter: true, dropdown_class: "dropdown-menu-user dropdown-menu-selectable dropdown-menu-assignee js-filter-submit",
              placeholder: "Search assignee", data: { first_user: current_user.try(:username), null_user: true, current_user: true, project_id: project.try(:id), selected: issuable.assignee_id, field_name: "#{issuable.class.model_name.param_key}[assignee_id]", default_label: "Assignee"} })
      .form-group.issue-milestone
        = f.label :milestone_id, "Milestone", class: "control-label #{"col-lg-4" if has_due_date}"
        .col-sm-10{ class: ("col-lg-8" if has_due_date) }
          .issuable-form-select-holder
            = render "shared/issuable/milestone_dropdown", selected: issuable.milestone, name: "#{issuable.class.model_name.param_key}[milestone_id]", show_any: false, show_upcoming: false, extra_class: "js-issuable-form-dropdown js-dropdown-keep-input", dropdown_title: "Select milestone"
      .form-group
        - has_labels = @labels && @labels.any?
        = f.label :label_ids, "Labels", class: "control-label #{"col-lg-4" if has_due_date}"
        = f.hidden_field :label_ids, multiple: true, value: ''
        .col-sm-10{ class: "#{"col-lg-8" if has_due_date} #{'issuable-form-padding-top' if !has_labels}" }
          .issuable-form-select-holder
            = render "shared/issuable/label_dropdown", classes: ["js-issuable-form-dropdown"], selected: issuable.labels, data_options: { field_name: "#{issuable.class.model_name.param_key}[label_ids][]", show_any: false, show_menu_above: 'true' }, dropdown_title: "Select label"

      - if issuable.respond_to?(:weight)
        .form-group
          = f.label :label_ids, class: "control-label #{"col-lg-4" if has_due_date}" do
            Weight
          .col-sm-10{ class: ("col-lg-8" if has_due_date) }
            = f.select :weight, issues_weight_options(issuable.weight, edit: true), { include_blank: true },
              { class: 'select2 js-select2', data: { placeholder: "Select weight" }}

    - if has_due_date
      .col-lg-6
        .form-group
          = f.label :due_date, "Due date", class: "control-label"
          .col-sm-10
            .issuable-form-select-holder
              = f.text_field :due_date, id: "issuable-due-date", class: "datepicker form-control", placeholder: "Select due date"

could be simplified by using partials:

= render 'metadata_form', issuable: issuable

and then the _metadata_form.html.haml could be as follows:

- return unless can?(current_user, :"admin_#{issuable.to_ability_name}", issuable.project)

- has_due_date = issuable.has_attribute?(:due_date)
%hr
.row
  %div{ class: (has_due_date ? "col-lg-6" : "col-sm-12") }
    .form-group.issue-assignee
      = f.label :assignee_id, "Assignee", class: "control-label #{"col-lg-4" if has_due_date}"
      .col-sm-10{ class: ("col-lg-8" if has_due_date) }
        .issuable-form-select-holder
          - if issuable.assignee_id
            = f.hidden_field :assignee_id
          = dropdown_tag(user_dropdown_label(issuable.assignee_id, "Assignee"), options: { toggle_class: "js-dropdown-keep-input js-user-search js-issuable-form-dropdown js-assignee-search", title: "Select assignee", filter: true, dropdown_class: "dropdown-menu-user dropdown-menu-selectable dropdown-menu-assignee js-filter-submit",
            placeholder: "Search assignee", data: { first_user: current_user.try(:username), null_user: true, current_user: true, project_id: project.try(:id), selected: issuable.assignee_id, field_name: "#{issuable.class.model_name.param_key}[assignee_id]", default_label: "Assignee"} })
    .form-group.issue-milestone
      = f.label :milestone_id, "Milestone", class: "control-label #{"col-lg-4" if has_due_date}"
      .col-sm-10{ class: ("col-lg-8" if has_due_date) }
        .issuable-form-select-holder
          = render "shared/issuable/milestone_dropdown", selected: issuable.milestone, name: "#{issuable.class.model_name.param_key}[milestone_id]", show_any: false, show_upcoming: false, extra_class: "js-issuable-form-dropdown js-dropdown-keep-input", dropdown_title: "Select milestone"
    .form-group
      - has_labels = @labels && @labels.any?
      = f.label :label_ids, "Labels", class: "control-label #{"col-lg-4" if has_due_date}"
      = f.hidden_field :label_ids, multiple: true, value: ''
      .col-sm-10{ class: "#{"col-lg-8" if has_due_date} #{'issuable-form-padding-top' if !has_labels}" }
        .issuable-form-select-holder
          = render "shared/issuable/label_dropdown", classes: ["js-issuable-form-dropdown"], selected: issuable.labels, data_options: { field_name: "#{issuable.class.model_name.param_key}[label_ids][]", show_any: false, show_menu_above: 'true' }, dropdown_title: "Select label"

    = render 'weight_form', issuable: issuable, has_due_date: has_due_date

  - if has_due_date
    .col-lg-6
      .form-group
        = f.label :due_date, "Due date", class: "control-label"
        .col-sm-10
          .issuable-form-select-holder
            = f.text_field :due_date, id: "issuable-due-date", class: "datepicker form-control", placeholder: "Select due date"

and then the _weight_form.html.haml could be as follows:

- return unless issuable.respond_to?(:weight)

- has_due_date = issuable.has_attribute?(:due_date)

.form-group
  = f.label :label_ids, class: "control-label #{"col-lg-4" if has_due_date}" do
    Weight
  .col-sm-10{ class: ("col-lg-8" if has_due_date) }
    = f.select :weight, issues_weight_options(issuable.weight, edit: true), { include_blank: true },
      { class: 'select2 js-select2', data: { placeholder: "Select weight" }}

Note:

• The safeguards at the top allow to get rid of an unneccessary indentation level
• Here we only moved the 'Weight' code to a partial since this is the only EE-specific code in that view, so it's the most likely to conflict, but you are encouraged to use partials even for code that's in CE to logically split big views into several smaller files.

Indentation issue

Sometimes a code block is indented more or less in EE because there's an additional condition.

Mitigations

Blocks of code that are EE-specific should be moved to partials as much as possible to avoid conflicts with big chunks of HAML code that that are not fun to resolve when you add the indentation in the equation.

---

Return to Development documentation