Merge branch 'improve-share-locking-feature-for-subgroups' into 'master'

Improve "Share with group lock" feature for subgroups

Closes #30550

See merge request !13944

20 files changed, 861 insertions, 134 deletions

diff --git a/app/helpers/groups_helper.rb b/app/helpers/groups_helper.rb
index eab1feb8a1f..36b79da1bde 100644
--- a/app/helpers/groups_helper.rb
+++ b/app/helpers/groups_helper.rb
@@ -3,6 +3,10 @@ module GroupsHelper
     can?(current_user, :change_visibility_level, group)
   end
 
+  def can_change_share_with_group_lock?(group)
+    can?(current_user, :change_share_with_group_lock, group)
+  end
+
   def group_icon(group)
     if group.is_a?(String)
       group = Group.find_by_full_path(group)
@@ -65,6 +69,20 @@ module GroupsHelper
       { group_name: group.name }
   end
 
+  def share_with_group_lock_help_text(group)
+    return default_help unless group.parent&.share_with_group_lock?
+
+    if group.share_with_group_lock?
+      if can?(current_user, :change_share_with_group_lock, group.parent)
+        ancestor_locked_but_you_can_override(group)
+      else
+        ancestor_locked_so_ask_the_owner(group)
+      end
+    else
+      ancestor_locked_and_has_been_overridden(group)
+    end
+  end
+
   private
 
   def group_title_link(group, hidable: false, show_avatar: false)
@@ -80,4 +98,45 @@ module GroupsHelper
       output.html_safe
     end
   end
+
+  def ancestor_group(group)
+    ancestor = oldest_consecutively_locked_ancestor(group)
+    if can?(current_user, :read_group, ancestor)
+      link_to ancestor.name, group_path(ancestor)
+    else
+      ancestor.name
+    end
+  end
+
+  def remove_the_share_with_group_lock_from_ancestor(group)
+    ancestor = oldest_consecutively_locked_ancestor(group)
+    text = s_("GroupSettings|remove the share with group lock from %{ancestor_group_name}") % { ancestor_group_name: ancestor.name }
+    if can?(current_user, :admin_group, ancestor)
+      link_to text, edit_group_path(ancestor)
+    else
+      text
+    end
+  end
+
+  def oldest_consecutively_locked_ancestor(group)
+    group.ancestors.find do |group|
+      !group.has_parent? || !group.parent.share_with_group_lock?
+    end
+  end
+
+  def default_help
+    s_("GroupSettings|This setting will be applied to all subgroups unless overridden by a group owner.")
+  end
+
+  def ancestor_locked_but_you_can_override(group)
+    s_("GroupSettings|This setting is applied on %{ancestor_group}. You can override the setting or %{remove_ancestor_share_with_group_lock}.").html_safe % { ancestor_group: ancestor_group(group), remove_ancestor_share_with_group_lock: remove_the_share_with_group_lock_from_ancestor(group) }
+  end
+
+  def ancestor_locked_so_ask_the_owner(group)
+    s_("GroupSettings|This setting is applied on %{ancestor_group}. To share projects in this group with another group, ask the owner to override the setting or %{remove_ancestor_share_with_group_lock}.").html_safe % { ancestor_group: ancestor_group(group), remove_ancestor_share_with_group_lock: remove_the_share_with_group_lock_from_ancestor(group) }
+  end
+
+  def ancestor_locked_and_has_been_overridden(group)
+    s_("GroupSettings|This setting is applied on %{ancestor_group} and has been overridden on this subgroup.").html_safe % { ancestor_group: ancestor_group(group) }
+  end
 end
diff --git a/app/models/namespace.rb b/app/models/namespace.rb
index e7cbc5170e8..4a9a23fea1f 100644
--- a/app/models/namespace.rb
+++ b/app/models/namespace.rb
@@ -44,6 +44,10 @@ class Namespace < ActiveRecord::Base
 
   after_commit :refresh_access_of_projects_invited_groups, on: :update, if: -> { previous_changes.key?('share_with_group_lock') }
 
+  before_create :sync_share_with_group_lock_with_parent
+  before_update :sync_share_with_group_lock_with_parent, if: :parent_changed?
+  after_update :force_share_with_group_lock_on_descendants, if: -> { share_with_group_lock_changed? && share_with_group_lock? }
+
   # Legacy Storage specific hooks
 
   after_update :move_dir, if: :path_changed?
@@ -219,4 +223,14 @@ class Namespace < ActiveRecord::Base
       errors.add(:parent_id, "has too deep level of nesting")
     end
   end
+
+  def sync_share_with_group_lock_with_parent
+    if parent&.share_with_group_lock?
+      self.share_with_group_lock = true
+    end
+  end
+
+  def force_share_with_group_lock_on_descendants
+    descendants.update_all(share_with_group_lock: true)
+  end
 end
diff --git a/app/policies/group_policy.rb b/app/policies/group_policy.rb
index 8ada661e571..d9fd6501419 100644
--- a/app/policies/group_policy.rb
+++ b/app/policies/group_policy.rb
@@ -15,6 +15,11 @@ class GroupPolicy < BasePolicy
 
   condition(:nested_groups_supported, scope: :global) { Group.supports_nested_groups? }
 
+  condition(:has_parent, scope: :subject) { @subject.has_parent? }
+  condition(:share_with_group_locked, scope: :subject) { @subject.share_with_group_lock? }
+  condition(:parent_share_with_group_locked, scope: :subject) { @subject.parent&.share_with_group_lock? }
+  condition(:can_change_parent_share_with_group_lock) { can?(:change_share_with_group_lock, @subject.parent) }
+
   condition(:has_projects) do
     GroupProjectsFinder.new(group: @subject, current_user: @user).execute.any?
   end
@@ -54,6 +59,8 @@ class GroupPolicy < BasePolicy
   rule { ~can?(:view_globally) }.prevent   :request_access
   rule { has_access }.prevent              :request_access
 
+  rule { owner & (~share_with_group_locked | ~has_parent | ~parent_share_with_group_locked | can_change_parent_share_with_group_lock) }.enable :change_share_with_group_lock
+
   def access_level
     return GroupMember::NO_ACCESS if @user.nil?
 
diff --git a/app/services/concerns/update_visibility_level.rb b/app/services/concerns/update_visibility_level.rb
new file mode 100644
index 00000000000..536fcc6acce
--- /dev/null
+++ b/app/services/concerns/update_visibility_level.rb
@@ -0,0 +1,15 @@
+module UpdateVisibilityLevel
+  def valid_visibility_level_change?(target, new_visibility)
+    # check that user is allowed to set specified visibility_level
+    if new_visibility && new_visibility.to_i != target.visibility_level
+      unless can?(current_user, :change_visibility_level, target) &&
+          Gitlab::VisibilityLevel.allowed_for?(current_user, new_visibility)
+
+        deny_visibility_level(target, new_visibility)
+        return false
+      end
+    end
+
+    true
+  end
+end
diff --git a/app/services/groups/update_service.rb b/app/services/groups/update_service.rb
index 1d65c76d282..08e3efb96e3 100644
--- a/app/services/groups/update_service.rb
+++ b/app/services/groups/update_service.rb
@@ -1,18 +1,13 @@
 module Groups
   class UpdateService < Groups::BaseService
+    include UpdateVisibilityLevel
+
     def execute
       reject_parent_id!
 
-      # check that user is allowed to set specified visibility_level
-      new_visibility = params[:visibility_level]
-      if new_visibility && new_visibility.to_i != group.visibility_level
-        unless can?(current_user, :change_visibility_level, group) &&
-            Gitlab::VisibilityLevel.allowed_for?(current_user, new_visibility)
+      return false unless valid_visibility_level_change?(group, params[:visibility_level])
 
-          deny_visibility_level(group, new_visibility)
-          return group
-        end
-      end
+      return false unless valid_share_with_group_lock_change?
 
       group.assign_attributes(params)
 
@@ -30,5 +25,19 @@ module Groups
     def reject_parent_id!
       params.except!(:parent_id)
     end
+
+    def valid_share_with_group_lock_change?
+      return true unless changing_share_with_group_lock?
+      return true if can?(current_user, :change_share_with_group_lock, group)
+
+      group.errors.add(:share_with_group_lock, s_('GroupSettings|cannot be disabled when the parent group "Share with group lock" is enabled, except by the owner of the parent group'))
+      false
+    end
+
+    def changing_share_with_group_lock?
+      return false if params[:share_with_group_lock].nil?
+
+      params[:share_with_group_lock] != group.share_with_group_lock
+    end
   end
 end
diff --git a/app/services/projects/update_service.rb b/app/services/projects/update_service.rb
index cf69007bc3b..cb4ffcab778 100644
--- a/app/services/projects/update_service.rb
+++ b/app/services/projects/update_service.rb
@@ -1,7 +1,9 @@
 module Projects
   class UpdateService < BaseService
+    include UpdateVisibilityLevel
+
     def execute
-      unless visibility_level_allowed?
+      unless valid_visibility_level_change?(project, params[:visibility_level])
         return error('New visibility level not allowed!')
       end
 
@@ -28,22 +30,6 @@ module Projects
 
     private
 
-    def visibility_level_allowed?
-      # check that user is allowed to set specified visibility_level
-      new_visibility = params[:visibility_level]
-
-      if new_visibility && new_visibility.to_i != project.visibility_level
-        unless can?(current_user, :change_visibility_level, project) &&
-            Gitlab::VisibilityLevel.allowed_for?(current_user, new_visibility)
-
-          deny_visibility_level(project, new_visibility)
-          return false
-        end
-      end
-
-      true
-    end
-
     def renaming_project_with_container_registry_tags?
       new_path = params[:path]
 
diff --git a/app/views/groups/edit.html.haml b/app/views/groups/edit.html.haml
index 839f23e69fd..0d3308833b7 100644
--- a/app/views/groups/edit.html.haml
+++ b/app/views/groups/edit.html.haml
@@ -28,17 +28,20 @@
         .col-sm-offset-2.col-sm-10
           = render 'shared/allow_request_access', form: f
 
-      = render 'group_admin_settings', f: f
-
       .form-group
-        %hr
-        = f.label :share_with_group_lock, class: 'control-label' do
-          Share with group lock
+        %label.control-label
+          = s_("GroupSettings|Share with group lock")
         .col-sm-10
           .checkbox
-            = f.check_box :share_with_group_lock
-            %span.descr Prevent sharing a project with another group within this group
+            = f.label :share_with_group_lock do
+              = f.check_box :share_with_group_lock, disabled: !can_change_share_with_group_lock?(@group)
+              %strong
+                - group_link = link_to @group.name, group_path(@group)
+                = s_("GroupSettings|Prevent sharing a project within %{group} with other groups").html_safe % { group: group_link }
+              %br
+              %span.descr= share_with_group_lock_help_text(@group)
 
+      = render 'group_admin_settings', f: f
 
       .form-actions
         = f.submit 'Save group', class: "btn btn-save"
diff --git a/changelogs/unreleased/improve-share-locking-feature-for-subgroups.yml b/changelogs/unreleased/improve-share-locking-feature-for-subgroups.yml
new file mode 100644
index 00000000000..ec0d1b245e4
--- /dev/null
+++ b/changelogs/unreleased/improve-share-locking-feature-for-subgroups.yml
@@ -0,0 +1,6 @@
+---
+title: '"Share with group lock" now applies to subgroups, but owner can override setting
+  on subgroups'
+merge_request: 13944
+author:
+type: changed
diff --git a/doc/user/group/img/share_with_group_lock.png b/doc/user/group/img/share_with_group_lock.png
index 8df41bf9465..c0f25389eaf 100644
--- a/doc/user/group/img/share_with_group_lock.png
+++ b/doc/user/group/img/share_with_group_lock.png
diff --git a/doc/user/group/index.md b/doc/user/group/index.md
index fbc05261a32..db0242f1324 100644
--- a/doc/user/group/index.md
+++ b/doc/user/group/index.md
@@ -168,8 +168,7 @@ GitLab administrators can use the admin interface to move any project to any nam
 You can [share your projects with a group](../project/members/share_project_with_groups.md)
 and give your group members access to the project all at once.
 
-Alternatively, with [GitLab Enterprise Edition Starter](https://about.gitlab.com/gitlab-ee/),
-you can [lock the sharing with group feature](#share-with-group-lock-ees-eep).
+Alternatively, you can [lock the sharing with group feature](#share-with-group-lock).
 
 ## Manage group memberships via LDAP
 
@@ -191,10 +190,28 @@ access further configurations for your group.
 
 #### Enforce 2FA to group members
 
-Add a secury layer to your group by
+Add a security layer to your group by
 [enforcing two-factor authentication (2FA)](../../security/two_factor_authentication.md#enforcing-2fa-for-all-users-in-a-group)
 to all group members.
 
+#### Share with group lock
+
+Prevent projects in a group from [sharing
+a project with another group](../project/members/share_project_with_groups.md).
+This allows for tighter control over project access.
+
+For example, consider you have two distinct teams (Group A and Group B)
+working together in a project.
+To inherit the group membership, you share the project between the
+two groups A and B. **Share with group lock** prevents any project within
+the group from being shared with another group. By doing so, you
+guarantee only the right group members have access to that projects.
+
+To enable this feature, navigate to the group settings page. Select
+**Share with group lock** and **Save the group**.
+
+![Checkbox for share with group lock](img/share_with_group_lock.png)
+
 #### Member Lock (EES/EEP)
 
 Available in [GitLab Enterprise Edition Starter](https://about.gitlab.com/gitlab-ee/),
@@ -203,15 +220,6 @@ level of members in group.
 
 Learn more about [Member Lock](https://docs.gitlab.com/ee/user/group/index.html#member-lock-ees-eep).
 
-#### Share with group lock (EES/EEP)
-
-In [GitLab Enterprise Edition Starter](https://about.gitlab.com/gitlab-ee/)
-it is possible to prevent projects in a group from [sharing
-a project with another group](../project/members/share_project_with_groups.md).
-This allows for tighter control over project access.
-
-Learn more about [Share with group lock](https://docs.gitlab.com/ee/user/group/index.html#share-with-group-lock-ees-eep).
-
 ### Advanced settings
 
 - **Projects**: view all projects within that group, add members to each project,
diff --git a/doc/user/project/members/share_project_with_groups.md b/doc/user/project/members/share_project_with_groups.md
index 25e5b897825..f5c748a03b3 100644
--- a/doc/user/project/members/share_project_with_groups.md
+++ b/doc/user/project/members/share_project_with_groups.md
@@ -22,7 +22,7 @@ To share 'Project Acme' with the 'Engineering' group, go to the project settings
 
 Then select the 'Share with group' tab by clicking it.
 
-Now you can add the 'Engineering' group with the maximum access level of your choice. Click 'Share' to share it. 
+Now you can add the 'Engineering' group with the maximum access level of your choice. Click 'Share' to share it.
 
 ![share project with groups tab](img/share_project_with_groups_tab.png)
 
@@ -34,11 +34,10 @@ After sharing 'Project Acme' with 'Engineering', the project will be listed on t
 
 In the example above, the maximum access level of 'Developer' for members from 'Engineering' means that users with higher access levels in 'Engineering' ('Master' or 'Owner') will only have 'Developer' access to 'Project Acme'.
 
-## Share project with group lock (EES/EEP)
+## Share project with group lock
 
-In [GitLab Enterprise Edition Starter](https://about.gitlab.com/gitlab-ee/)
-it is possible to prevent projects in a group from [sharing
+It is possible to prevent projects in a group from [sharing
 a project with another group](../members/share_project_with_groups.md).
 This allows for tighter control over project access.
 
-Learn more about [Share with group lock](https://docs.gitlab.com/ee/user/group/index.html#share-with-group-lock-ees-eep).
+Learn more about [Share with group lock](../../group/index.html#share-with-group-lock).
diff --git a/spec/features/groups/share_lock_spec.rb b/spec/features/groups/share_lock_spec.rb
new file mode 100644
index 00000000000..8842d1391aa
--- /dev/null
+++ b/spec/features/groups/share_lock_spec.rb
@@ -0,0 +1,62 @@
+require 'spec_helper'
+
+feature 'Group share with group lock' do
+  given(:root_owner) { create(:user) }
+  given(:root_group) { create(:group) }
+
+  background do
+    root_group.add_owner(root_owner)
+    sign_in(root_owner)
+  end
+
+  context 'with a subgroup', :nested_groups do
+    given!(:subgroup) { create(:group, parent: root_group) }
+
+    context 'when enabling the parent group share with group lock' do
+      scenario 'the subgroup share with group lock becomes enabled' do
+        visit edit_group_path(root_group)
+        check 'group_share_with_group_lock'
+
+        click_on 'Save group'
+
+        expect(subgroup.reload.share_with_group_lock?).to be_truthy
+      end
+    end
+
+    context 'when disabling the parent group share with group lock (which was already enabled)' do
+      background do
+        visit edit_group_path(root_group)
+        check 'group_share_with_group_lock'
+        click_on 'Save group'
+      end
+
+      context 'and the subgroup share with group lock is enabled' do
+        scenario 'the subgroup share with group lock does not change' do
+          visit edit_group_path(root_group)
+          uncheck 'group_share_with_group_lock'
+
+          click_on 'Save group'
+
+          expect(subgroup.reload.share_with_group_lock?).to be_truthy
+        end
+      end
+
+      context 'but the subgroup share with group lock is disabled' do
+        background do
+          visit edit_group_path(subgroup)
+          uncheck 'group_share_with_group_lock'
+          click_on 'Save group'
+        end
+
+        scenario 'the subgroup share with group lock does not change' do
+          visit edit_group_path(root_group)
+          uncheck 'group_share_with_group_lock'
+
+          click_on 'Save group'
+
+          expect(subgroup.reload.share_with_group_lock?).to be_falsey
+        end
+      end
+    end
+  end
+end
diff --git a/spec/features/projects/group_links_spec.rb b/spec/features/projects/group_links_spec.rb
deleted file mode 100644
index 5195d027a9f..00000000000
--- a/spec/features/projects/group_links_spec.rb
+++ /dev/null
@@ -1,77 +0,0 @@
-require 'spec_helper'
-
-feature 'Project group links', :js do
-  include Select2Helper
-
-  let(:master) { create(:user) }
-  let(:project) { create(:project) }
-  let!(:group) { create(:group) }
-
-  background do
-    project.add_master(master)
-    sign_in(master)
-  end
-
-  context 'setting an expiration date for a group link' do
-    before do
-      visit project_settings_members_path(project)
-
-      click_on 'share-with-group-tab'
-
-      select2 group.id, from: '#link_group_id'
-      fill_in 'expires_at_groups', with: (Time.current + 4.5.days).strftime('%Y-%m-%d')
-      page.find('body').click
-      find('.btn-create').trigger('click')
-    end
-
-    it 'shows the expiration time with a warning class' do
-      page.within('.project-members-groups') do
-        expect(page).to have_content('Expires in 4 days')
-        expect(page).to have_selector('.text-warning')
-      end
-    end
-  end
-
-  context 'nested group project' do
-    let!(:nested_group) { create(:group, parent: group) }
-    let!(:another_group) { create(:group) }
-    let!(:project) { create(:project, namespace: nested_group) }
-
-    background do
-      group.add_master(master)
-      another_group.add_master(master)
-    end
-
-    it 'does not show ancestors', :nested_groups do
-      visit project_settings_members_path(project)
-
-      click_on 'share-with-group-tab'
-      click_link 'Search for a group'
-
-      page.within '.select2-drop' do
-        expect(page).to have_content(another_group.name)
-        expect(page).not_to have_content(group.name)
-      end
-    end
-  end
-
-  describe 'the groups dropdown' do
-    before do
-      group_two = create(:group)
-      group.add_owner(master)
-      group_two.add_owner(master)
-
-      visit project_settings_members_path(project)
-      execute_script 'GroupsSelect.PER_PAGE = 1;'
-      open_select2 '#link_group_id'
-    end
-
-    it 'should infinitely scroll' do
-      expect(find('.select2-drop .select2-results')).to have_selector('.select2-result', count: 1)
-
-      scroll_select2_to_bottom('.select2-drop .select2-results:visible')
-
-      expect(find('.select2-drop .select2-results')).to have_selector('.select2-result', count: 2)
-    end
-  end
-end
diff --git a/spec/features/projects/members/group_links_spec.rb b/spec/features/projects/members/groups_with_access_list_spec.rb
index 1c348b987d4..9950272af08 100644
--- a/spec/features/projects/members/group_links_spec.rb
+++ b/spec/features/projects/members/groups_with_access_list_spec.rb
@@ -1,6 +1,6 @@
 require 'spec_helper'
 
-feature 'Projects > Members > Anonymous user sees members', js: true do
+feature 'Projects > Members > Groups with access list', js: true do
   let(:user) { create(:user) }
   let(:group) { create(:group, :public) }
   let(:project) { create(:project, :public) }
@@ -13,7 +13,7 @@ feature 'Projects > Members > Anonymous user sees members', js: true do
     visit project_settings_members_path(project)
   end
 
-  it 'updates group access level' do
+  scenario 'updates group access level' do
     click_button @group_link.human_access
 
     page.within '.dropdown-menu' do
@@ -27,7 +27,7 @@ feature 'Projects > Members > Anonymous user sees members', js: true do
     expect(first('.group_member')).to have_content('Guest')
   end
 
-  it 'updates expiry date' do
+  scenario 'updates expiry date' do
     tomorrow = Date.today + 3
 
     fill_in "member_expires_at_#{group.id}", with: tomorrow.strftime("%F")
@@ -38,7 +38,7 @@ feature 'Projects > Members > Anonymous user sees members', js: true do
     end
   end
 
-  it 'deletes group link' do
+  scenario 'deletes group link' do
     page.within(first('.group_member')) do
       find('.btn-remove').click
     end
@@ -47,8 +47,8 @@ feature 'Projects > Members > Anonymous user sees members', js: true do
     expect(page).not_to have_selector('.group_member')
   end
 
-  context 'search' do
-    it 'finds no results' do
+  context 'search in existing members (yes, this filters the groups list as well)' do
+    scenario 'finds no results' do
       page.within '.member-search-form' do
         fill_in 'search', with: 'testing 123'
         find('.member-search-btn').click
@@ -57,7 +57,7 @@ feature 'Projects > Members > Anonymous user sees members', js: true do
       expect(page).not_to have_selector('.group_member')
     end
 
-    it 'finds results' do
+    scenario 'finds results' do
       page.within '.member-search-form' do
         fill_in 'search', with: group.name
         find('.member-search-btn').click
diff --git a/spec/features/projects/members/share_with_group_spec.rb b/spec/features/projects/members/share_with_group_spec.rb
new file mode 100644
index 00000000000..3b368f8e25d
--- /dev/null
+++ b/spec/features/projects/members/share_with_group_spec.rb
@@ -0,0 +1,191 @@
+require 'spec_helper'
+
+feature 'Project > Members > Share with Group', :js do
+  include Select2Helper
+  include ActionView::Helpers::DateHelper
+
+  let(:master) { create(:user) }
+
+  describe 'Share with group lock' do
+    shared_examples 'the project can be shared with groups' do
+      scenario 'the "Share with group" tab exists' do
+        visit project_settings_members_path(project)
+        expect(page).to have_selector('#share-with-group-tab')
+      end
+    end
+
+    shared_examples 'the project cannot be shared with groups' do
+      scenario 'the "Share with group" tab does not exist' do
+        visit project_settings_members_path(project)
+        expect(page).to have_selector('#add-member-tab')
+        expect(page).not_to have_selector('#share-with-group-tab')
+      end
+    end
+
+    context 'for a project in a root group' do
+      let!(:group_to_share_with) { create(:group) }
+      let(:project) { create(:project, namespace: create(:group)) }
+
+      background do
+        project.add_master(master)
+        sign_in(master)
+      end
+
+      context 'when the group has "Share with group lock" disabled' do
+        it_behaves_like 'the project can be shared with groups'
+
+        scenario 'the project can be shared with another group' do
+          visit project_settings_members_path(project)
+
+          click_on 'share-with-group-tab'
+
+          select2 group_to_share_with.id, from: '#link_group_id'
+          page.find('body').click
+          find('.btn-create').trigger('click')
+
+          page.within('.project-members-groups') do
+            expect(page).to have_content(group_to_share_with.name)
+          end
+        end
+      end
+
+      context 'when the group has "Share with group lock" enabled' do
+        before do
+          project.namespace.update_column(:share_with_group_lock, true)
+        end
+
+        it_behaves_like 'the project cannot be shared with groups'
+      end
+    end
+
+    context 'for a project in a subgroup', :nested_groups do
+      let!(:group_to_share_with) { create(:group) }
+      let(:root_group) { create(:group) }
+      let(:subgroup) { create(:group, parent: root_group) }
+      let(:project) { create(:project, namespace: subgroup) }
+
+      background do
+        project.add_master(master)
+        sign_in(master)
+      end
+
+      context 'when the root_group has "Share with group lock" disabled' do
+        context 'when the subgroup has "Share with group lock" disabled' do
+          it_behaves_like 'the project can be shared with groups'
+        end
+
+        context 'when the subgroup has "Share with group lock" enabled' do
+          before do
+            subgroup.update_column(:share_with_group_lock, true)
+          end
+
+          it_behaves_like 'the project cannot be shared with groups'
+        end
+      end
+
+      context 'when the root_group has "Share with group lock" enabled' do
+        before do
+          root_group.update_column(:share_with_group_lock, true)
+        end
+
+        context 'when the subgroup has "Share with group lock" disabled (parent overridden)' do
+          it_behaves_like 'the project can be shared with groups'
+        end
+
+        context 'when the subgroup has "Share with group lock" enabled' do
+          before do
+            subgroup.update_column(:share_with_group_lock, true)
+          end
+
+          it_behaves_like 'the project cannot be shared with groups'
+        end
+      end
+    end
+  end
+
+  describe 'setting an expiration date for a group link' do
+    let(:project) { create(:project) }
+    let!(:group) { create(:group) }
+
+    around do |example|
+      Timecop.freeze { example.run }
+    end
+
+    before do
+      project.add_master(master)
+      sign_in(master)
+
+      visit project_settings_members_path(project)
+
+      click_on 'share-with-group-tab'
+
+      select2 group.id, from: '#link_group_id'
+
+      fill_in 'expires_at_groups', with: (Time.now + 4.5.days).strftime('%Y-%m-%d')
+      page.find('body').click
+      find('.btn-create').trigger('click')
+    end
+
+    scenario 'the group link shows the expiration time with a warning class' do
+      page.within('.project-members-groups') do
+        # Using distance_of_time_in_words_to_now because it is not the same as
+        # subtraction, and this way avoids time zone issues as well
+        expires_in_text = distance_of_time_in_words_to_now(project.project_group_links.first.expires_at)
+        expect(page).to have_content(expires_in_text)
+        expect(page).to have_selector('.text-warning')
+      end
+    end
+  end
+
+  describe 'the groups dropdown' do
+    context 'with multiple groups to choose from' do
+      let(:project) { create(:project) }
+
+      background do
+        project.add_master(master)
+        sign_in(master)
+
+        create(:group).add_owner(master)
+        create(:group).add_owner(master)
+
+        visit project_settings_members_path(project)
+        execute_script 'GroupsSelect.PER_PAGE = 1;'
+        open_select2 '#link_group_id'
+      end
+
+      it 'should infinitely scroll' do
+        expect(find('.select2-drop .select2-results')).to have_selector('.select2-result', count: 1)
+
+        scroll_select2_to_bottom('.select2-drop .select2-results:visible')
+
+        expect(find('.select2-drop .select2-results')).to have_selector('.select2-result', count: 2)
+      end
+    end
+
+    context 'for a project in a nested group' do
+      let(:group) { create(:group) }
+      let!(:nested_group) { create(:group, parent: group) }
+      let!(:group_to_share_with) { create(:group) }
+      let!(:project) { create(:project, namespace: nested_group) }
+
+      background do
+        project.add_master(master)
+        sign_in(master)
+        group.add_master(master)
+        group_to_share_with.add_master(master)
+      end
+
+      scenario 'the groups dropdown does not show ancestors', :nested_groups do
+        visit project_settings_members_path(project)
+
+        click_on 'share-with-group-tab'
+        click_link 'Search for a group'
+
+        page.within '.select2-drop' do
+          expect(page).to have_content(group_to_share_with.name)
+          expect(page).not_to have_content(group.name)
+        end
+      end
+    end
+  end
+end
diff --git a/spec/helpers/groups_helper_spec.rb b/spec/helpers/groups_helper_spec.rb
index 05f969904f5..36031ac1a28 100644
--- a/spec/helpers/groups_helper_spec.rb
+++ b/spec/helpers/groups_helper_spec.rb
@@ -95,4 +95,97 @@ describe GroupsHelper do
         .to match(/<li style="text-indent: 16px;"><a.*>#{deep_nested_group.name}.*<\/li>.*<a.*>#{very_deep_nested_group.name}<\/a>/m)
     end
   end
+
+  # rubocop:disable Layout/SpaceBeforeComma
+  describe '#share_with_group_lock_help_text', :nested_groups do
+    let!(:root_group) { create(:group) }
+    let!(:subgroup) { create(:group, parent: root_group) }
+    let!(:sub_subgroup) { create(:group, parent: subgroup) }
+    let(:root_owner) { create(:user) }
+    let(:sub_owner) { create(:user) }
+    let(:sub_sub_owner) { create(:user) }
+    let(:possible_help_texts) do
+      {
+        default_help: "This setting will be applied to all subgroups unless overridden by a group owner",
+        ancestor_locked_but_you_can_override: /This setting is applied on <a .+>.+<\/a>\. You can override the setting or .+/,
+        ancestor_locked_so_ask_the_owner: /This setting is applied on .+\. To share projects in this group with another group, ask the owner to override the setting or remove the share with group lock from .+/,
+        ancestor_locked_and_has_been_overridden: /This setting is applied on .+ and has been overridden on this subgroup/
+      }
+    end
+    let(:possible_linked_ancestors) do
+      {
+        root_group: root_group,
+        subgroup: subgroup
+      }
+    end
+    let(:users) do
+      {
+        root_owner: root_owner,
+        sub_owner: sub_owner,
+        sub_sub_owner: sub_sub_owner
+      }
+    end
+    subject { helper.share_with_group_lock_help_text(sub_subgroup) }
+
+    where(:root_share_with_group_locked, :subgroup_share_with_group_locked, :sub_subgroup_share_with_group_locked, :current_user, :help_text, :linked_ancestor) do
+      [
+        [false , false , false , :root_owner     , :default_help                            , nil],
+        [false , false , false , :sub_owner      , :default_help                            , nil],
+        [false , false , false , :sub_sub_owner  , :default_help                            , nil],
+        [false , false , true  , :root_owner     , :default_help                            , nil],
+        [false , false , true  , :sub_owner      , :default_help                            , nil],
+        [false , false , true  , :sub_sub_owner  , :default_help                            , nil],
+        [false , true  , false , :root_owner     , :ancestor_locked_and_has_been_overridden , :subgroup],
+        [false , true  , false , :sub_owner      , :ancestor_locked_and_has_been_overridden , :subgroup],
+        [false , true  , false , :sub_sub_owner  , :ancestor_locked_and_has_been_overridden , :subgroup],
+        [false , true  , true  , :root_owner     , :ancestor_locked_but_you_can_override    , :subgroup],
+        [false , true  , true  , :sub_owner      , :ancestor_locked_but_you_can_override    , :subgroup],
+        [false , true  , true  , :sub_sub_owner  , :ancestor_locked_so_ask_the_owner        , :subgroup],
+        [true  , false , false , :root_owner     , :default_help                            , nil],
+        [true  , false , false , :sub_owner      , :default_help                            , nil],
+        [true  , false , false , :sub_sub_owner  , :default_help                            , nil],
+        [true  , false , true  , :root_owner     , :default_help                            , nil],
+        [true  , false , true  , :sub_owner      , :default_help                            , nil],
+        [true  , false , true  , :sub_sub_owner  , :default_help                            , nil],
+        [true  , true  , false , :root_owner     , :ancestor_locked_and_has_been_overridden , :root_group],
+        [true  , true  , false , :sub_owner      , :ancestor_locked_and_has_been_overridden , :root_group],
+        [true  , true  , false , :sub_sub_owner  , :ancestor_locked_and_has_been_overridden , :root_group],
+        [true  , true  , true  , :root_owner     , :ancestor_locked_but_you_can_override    , :root_group],
+        [true  , true  , true  , :sub_owner      , :ancestor_locked_so_ask_the_owner        , :root_group],
+        [true  , true  , true  , :sub_sub_owner  , :ancestor_locked_so_ask_the_owner        , :root_group]
+      ]
+    end
+
+    with_them do
+      before do
+        root_group.add_owner(root_owner)
+        subgroup.add_owner(sub_owner)
+        sub_subgroup.add_owner(sub_sub_owner)
+
+        root_group.update_column(:share_with_group_lock, true) if root_share_with_group_locked
+        subgroup.update_column(:share_with_group_lock, true) if subgroup_share_with_group_locked
+        sub_subgroup.update_column(:share_with_group_lock, true) if sub_subgroup_share_with_group_locked
+
+        allow(helper).to receive(:current_user).and_return(users[current_user])
+        allow(helper).to receive(:can?)
+                           .with(users[current_user], :change_share_with_group_lock, subgroup)
+                           .and_return(Ability.allowed?(users[current_user], :change_share_with_group_lock, subgroup))
+
+        ancestor = possible_linked_ancestors[linked_ancestor]
+        if ancestor
+          allow(helper).to receive(:can?)
+                             .with(users[current_user], :read_group, ancestor)
+                             .and_return(Ability.allowed?(users[current_user], :read_group, ancestor))
+          allow(helper).to receive(:can?)
+                             .with(users[current_user], :admin_group, ancestor)
+                             .and_return(Ability.allowed?(users[current_user], :admin_group, ancestor))
+        end
+      end
+
+      it 'has the correct help text with correct ancestor links' do
+        expect(subject).to match(possible_help_texts[help_text])
+        expect(subject).to match(possible_linked_ancestors[linked_ancestor].name) unless help_text == :default_help
+      end
+    end
+  end
 end
diff --git a/spec/models/namespace_spec.rb b/spec/models/namespace_spec.rb
index f5f83f0f114..81d5ab7a6d3 100644
--- a/spec/models/namespace_spec.rb
+++ b/spec/models/namespace_spec.rb
@@ -406,4 +406,116 @@ describe Namespace do
 
     it { expect(group.all_projects.to_a).to match_array([project2, project1]) }
   end
+
+  describe '#share_with_group_lock with subgroups', :nested_groups do
+    context 'when creating a subgroup' do
+      let(:subgroup) { create(:group, parent: root_group )}
+
+      context 'under a parent with "Share with group lock" enabled' do
+        let(:root_group) { create(:group, share_with_group_lock: true) }
+
+        it 'enables "Share with group lock" on the subgroup' do
+          expect(subgroup.share_with_group_lock).to be_truthy
+        end
+      end
+
+      context 'under a parent with "Share with group lock" disabled' do
+        let(:root_group) { create(:group) }
+
+        it 'does not enable "Share with group lock" on the subgroup' do
+          expect(subgroup.share_with_group_lock).to be_falsey
+        end
+      end
+    end
+
+    context 'when enabling the parent group "Share with group lock"' do
+      let(:root_group) { create(:group) }
+      let!(:subgroup) { create(:group, parent: root_group )}
+
+      it 'the subgroup "Share with group lock" becomes enabled' do
+        root_group.update!(share_with_group_lock: true)
+
+        expect(subgroup.reload.share_with_group_lock).to be_truthy
+      end
+    end
+
+    context 'when disabling the parent group "Share with group lock" (which was already enabled)' do
+      let(:root_group) { create(:group, share_with_group_lock: true) }
+
+      context 'and the subgroup "Share with group lock" is enabled' do
+        let(:subgroup) { create(:group, parent: root_group, share_with_group_lock: true )}
+
+        it 'the subgroup "Share with group lock" does not change' do
+          root_group.update!(share_with_group_lock: false)
+
+          expect(subgroup.reload.share_with_group_lock).to be_truthy
+        end
+      end
+
+      context 'but the subgroup "Share with group lock" is disabled' do
+        let(:subgroup) { create(:group, parent: root_group )}
+
+        it 'the subgroup "Share with group lock" does not change' do
+          root_group.update!(share_with_group_lock: false)
+
+          expect(subgroup.reload.share_with_group_lock?).to be_falsey
+        end
+      end
+    end
+
+    # Note: Group transfers are not yet implemented
+    context 'when a group is transferred into a root group' do
+      context 'when the root group "Share with group lock" is enabled' do
+        let(:root_group) { create(:group, share_with_group_lock: true) }
+
+        context 'when the subgroup "Share with group lock" is enabled' do
+          let(:subgroup) { create(:group, share_with_group_lock: true )}
+
+          it 'the subgroup "Share with group lock" does not change' do
+            subgroup.parent = root_group
+            subgroup.save!
+
+            expect(subgroup.share_with_group_lock).to be_truthy
+          end
+        end
+
+        context 'when the subgroup "Share with group lock" is disabled' do
+          let(:subgroup) { create(:group)}
+
+          it 'the subgroup "Share with group lock" becomes enabled' do
+            subgroup.parent = root_group
+            subgroup.save!
+
+            expect(subgroup.share_with_group_lock).to be_truthy
+          end
+        end
+      end
+
+      context 'when the root group "Share with group lock" is disabled' do
+        let(:root_group) { create(:group) }
+
+        context 'when the subgroup "Share with group lock" is enabled' do
+          let(:subgroup) { create(:group, share_with_group_lock: true )}
+
+          it 'the subgroup "Share with group lock" does not change' do
+            subgroup.parent = root_group
+            subgroup.save!
+
+            expect(subgroup.share_with_group_lock).to be_truthy
+          end
+        end
+
+        context 'when the subgroup "Share with group lock" is disabled' do
+          let(:subgroup) { create(:group)}
+
+          it 'the subgroup "Share with group lock" does not change' do
+            subgroup.parent = root_group
+            subgroup.save!
+
+            expect(subgroup.share_with_group_lock).to be_falsey
+          end
+        end
+      end
+    end
+  end
 end
diff --git a/spec/policies/group_policy_spec.rb b/spec/policies/group_policy_spec.rb
index 7f832bfa563..0c4044dc7ab 100644
--- a/spec/policies/group_policy_spec.rb
+++ b/spec/policies/group_policy_spec.rb
@@ -242,4 +242,94 @@ describe GroupPolicy do
       end
     end
   end
+
+  describe 'change_share_with_group_lock' do
+    context 'when the current_user owns the group' do
+      let(:current_user) { owner }
+
+      context 'when the group share_with_group_lock is enabled' do
+        let(:group) { create(:group, share_with_group_lock: true, parent: parent) }
+
+        context 'when the parent group share_with_group_lock is enabled' do
+          context 'when the group has a grandparent' do
+            let(:parent) { create(:group, share_with_group_lock: true, parent: grandparent) }
+
+            context 'when the grandparent share_with_group_lock is enabled' do
+              let(:grandparent) { create(:group, share_with_group_lock: true) }
+
+              context 'when the current_user owns the parent' do
+                before do
+                  parent.add_owner(current_user)
+                end
+
+                context 'when the current_user owns the grandparent' do
+                  before do
+                    grandparent.add_owner(current_user)
+                  end
+
+                  it { expect_allowed(:change_share_with_group_lock) }
+                end
+
+                context 'when the current_user does not own the grandparent' do
+                  it { expect_disallowed(:change_share_with_group_lock) }
+                end
+              end
+
+              context 'when the current_user does not own the parent' do
+                it { expect_disallowed(:change_share_with_group_lock) }
+              end
+            end
+
+            context 'when the grandparent share_with_group_lock is disabled' do
+              let(:grandparent) { create(:group) }
+
+              context 'when the current_user owns the parent' do
+                before do
+                  parent.add_owner(current_user)
+                end
+
+                it { expect_allowed(:change_share_with_group_lock) }
+              end
+
+              context 'when the current_user does not own the parent' do
+                it { expect_disallowed(:change_share_with_group_lock) }
+              end
+            end
+          end
+
+          context 'when the group does not have a grandparent' do
+            let(:parent) { create(:group, share_with_group_lock: true) }
+
+            context 'when the current_user owns the parent' do
+              before do
+                parent.add_owner(current_user)
+              end
+
+              it { expect_allowed(:change_share_with_group_lock) }
+            end
+
+            context 'when the current_user does not own the parent' do
+              it { expect_disallowed(:change_share_with_group_lock) }
+            end
+          end
+        end
+
+        context 'when the parent group share_with_group_lock is disabled' do
+          let(:parent) { create(:group) }
+
+          it { expect_allowed(:change_share_with_group_lock) }
+        end
+      end
+
+      context 'when the group share_with_group_lock is disabled' do
+        it { expect_allowed(:change_share_with_group_lock) }
+      end
+    end
+
+    context 'when the current_user does not own the group' do
+      let(:current_user) { create(:user) }
+
+      it { expect_disallowed(:change_share_with_group_lock) }
+    end
+  end
 end
diff --git a/spec/services/groups/update_service_spec.rb b/spec/services/groups/update_service_spec.rb
index 44f22a3b37b..1737fd0a9fc 100644
--- a/spec/services/groups/update_service_spec.rb
+++ b/spec/services/groups/update_service_spec.rb
@@ -100,4 +100,38 @@ describe Groups::UpdateService do
       end
     end
   end
+
+  context 'for a subgroup', :nested_groups do
+    let(:subgroup) { create(:group, :private, parent: private_group) }
+
+    context 'when the parent group share_with_group_lock is enabled' do
+      before do
+        private_group.update_column(:share_with_group_lock, true)
+      end
+
+      context 'for the parent group owner' do
+        it 'allows disabling share_with_group_lock' do
+          private_group.add_owner(user)
+
+          result = described_class.new(subgroup, user, share_with_group_lock: false).execute
+
+          expect(result).to be_truthy
+          expect(subgroup.reload.share_with_group_lock).to be_falsey
+        end
+      end
+
+      context 'for a subgroup owner (who does not own the parent)' do
+        it 'does not allow disabling share_with_group_lock' do
+          subgroup_owner = create(:user)
+          subgroup.add_owner(subgroup_owner)
+
+          result = described_class.new(subgroup, subgroup_owner, share_with_group_lock: false).execute
+
+          expect(result).to be_falsey
+          expect(subgroup.errors.full_messages.first).to match(/cannot be disabled when the parent group "Share with group lock" is enabled, except by the owner of the parent group/)
+          expect(subgroup.reload.share_with_group_lock).to be_truthy
+        end
+      end
+    end
+  end
 end
diff --git a/spec/views/groups/edit.html.haml_spec.rb b/spec/views/groups/edit.html.haml_spec.rb
new file mode 100644
index 00000000000..38cfb84f0d5
--- /dev/null
+++ b/spec/views/groups/edit.html.haml_spec.rb
@@ -0,0 +1,116 @@
+require 'spec_helper'
+
+describe 'groups/edit.html.haml' do
+  include Devise::Test::ControllerHelpers
+
+  describe '"Share with group lock" setting' do
+    let(:root_owner) { create(:user) }
+    let(:root_group) { create(:group) }
+
+    before do
+      root_group.add_owner(root_owner)
+    end
+
+    shared_examples_for '"Share with group lock" setting' do |checkbox_options|
+      it 'should have the correct label, help text, and checkbox options' do
+        assign(:group, test_group)
+        allow(view).to receive(:can?).with(test_user, :admin_group, test_group).and_return(true)
+        allow(view).to receive(:can_change_group_visibility_level?).and_return(false)
+        allow(view).to receive(:current_user).and_return(test_user)
+        expect(view).to receive(:can_change_share_with_group_lock?).and_return(!checkbox_options[:disabled])
+        expect(view).to receive(:share_with_group_lock_help_text).and_return('help text here')
+
+        render
+
+        expect(rendered).to have_content("Prevent sharing a project within #{test_group.name} with other groups")
+        expect(rendered).to have_css('.descr', text: 'help text here')
+        expect(rendered).to have_field('group_share_with_group_lock', checkbox_options)
+      end
+    end
+
+    context 'for a root group' do
+      let(:test_group) { root_group }
+      let(:test_user) { root_owner }
+
+      it_behaves_like '"Share with group lock" setting', { disabled: false, checked: false }
+    end
+
+    context 'for a subgroup', :nested_groups do
+      let!(:subgroup) { create(:group, parent: root_group) }
+      let(:sub_owner) { create(:user) }
+      let(:test_group) { subgroup }
+
+      context 'when the root_group has "Share with group lock" disabled' do
+        context 'when the subgroup has "Share with group lock" disabled' do
+          context 'as the root_owner' do
+            let(:test_user) { root_owner }
+
+            it_behaves_like '"Share with group lock" setting', { disabled: false, checked: false }
+          end
+
+          context 'as the sub_owner' do
+            let(:test_user) { sub_owner }
+
+            it_behaves_like '"Share with group lock" setting', { disabled: false, checked: false }
+          end
+        end
+
+        context 'when the subgroup has "Share with group lock" enabled' do
+          before do
+            subgroup.update_column(:share_with_group_lock, true)
+          end
+
+          context 'as the root_owner' do
+            let(:test_user) { root_owner }
+
+            it_behaves_like '"Share with group lock" setting', { disabled: false, checked: true }
+          end
+
+          context 'as the sub_owner' do
+            let(:test_user) { sub_owner }
+
+            it_behaves_like '"Share with group lock" setting', { disabled: false, checked: true }
+          end
+        end
+      end
+
+      context 'when the root_group has "Share with group lock" enabled' do
+        before do
+          root_group.update_column(:share_with_group_lock, true)
+        end
+
+        context 'when the subgroup has "Share with group lock" disabled (parent overridden)' do
+          context 'as the root_owner' do
+            let(:test_user) { root_owner }
+
+            it_behaves_like '"Share with group lock" setting', { disabled: false, checked: false }
+          end
+
+          context 'as the sub_owner' do
+            let(:test_user) { sub_owner }
+
+            it_behaves_like '"Share with group lock" setting', { disabled: false, checked: false }
+          end
+        end
+
+        context 'when the subgroup has "Share with group lock" enabled (same as parent)' do
+          before do
+            subgroup.update_column(:share_with_group_lock, true)
+          end
+
+          context 'as the root_owner' do
+            let(:test_user) { root_owner }
+
+            it_behaves_like '"Share with group lock" setting', { disabled: false, checked: true }
+          end
+
+          context 'as the sub_owner' do
+            let(:test_user) { sub_owner }
+
+            it_behaves_like '"Share with group lock" setting', { disabled: true, checked: true }
+          end
+        end
+      end
+    end
+  end
+end