Refactor visibility level helper

Contributes to https://gitlab.com/gitlab-org/gitlab/-/issues/250681

* Remove unused methods
  `disallowed_project_visibility_level_description`
  `disallowed_group_visibility_level_description`
  `visibility_level_errors_for_group`

* Move locally used methods to the private scope (for consistency)
  `project_visibility_level_description`
  `group_visibility_level_description`
  `project_visibility_icon_description`
  `group_visibility_icon_description`

app/helpers/visibility_level_helper.rb

@@ -26,76 +26,6 @@ module VisibilityLevelHelper
     end
   end
 
-  def project_visibility_level_description(level)
-    case level
-    when Gitlab::VisibilityLevel::PRIVATE
-      _("Project access must be granted explicitly to each user. If this project is part of a group, access will be granted to members of the group.")
-    when Gitlab::VisibilityLevel::INTERNAL
-      _("The project can be accessed by any logged in user except external users.")
-    when Gitlab::VisibilityLevel::PUBLIC
-      _("The project can be accessed without any authentication.")
-    end
-  end
-
-  def group_visibility_level_description(level)
-    case level
-    when Gitlab::VisibilityLevel::PRIVATE
-      _("The group and its projects can only be viewed by members.")
-    when Gitlab::VisibilityLevel::INTERNAL
-      _("The group and any internal projects can be viewed by any logged in user except external users.")
-    when Gitlab::VisibilityLevel::PUBLIC
-      _("The group and any public projects can be viewed without any authentication.")
-    end
-  end
-
-  # Note: these messages closely mirror the form validation strings found in the project
-  # model and any changes or additons to these may also need to be made there.
-  def disallowed_project_visibility_level_description(level, project)
-    level_name = Gitlab::VisibilityLevel.level_name(level).downcase
-    reasons = []
-    instructions = []
-
-    unless project.visibility_level_allowed_as_fork?(level)
-      reasons << "the fork source project has lower visibility"
-    end
-
-    unless project.visibility_level_allowed_by_group?(level)
-      errors = visibility_level_errors_for_group(project.group, level_name)
-
-      reasons << errors[:reason]
-      instructions << errors[:instruction]
-    end
-
-    reasons = reasons.any? ? ' because ' + reasons.to_sentence : ''
-    "This project cannot be #{level_name}#{reasons}.#{instructions.join}".html_safe
-  end
-
-  # Note: these messages closely mirror the form validation strings found in the group
-  # model and any changes or additons to these may also need to be made there.
-  def disallowed_group_visibility_level_description(level, group)
-    level_name = Gitlab::VisibilityLevel.level_name(level).downcase
-    reasons = []
-    instructions = []
-
-    unless group.visibility_level_allowed_by_projects?(level)
-      reasons << "it contains projects with higher visibility"
-    end
-
-    unless group.visibility_level_allowed_by_sub_groups?(level)
-      reasons << "it contains sub-groups with higher visibility"
-    end
-
-    unless group.visibility_level_allowed_by_parent?(level)
-      errors = visibility_level_errors_for_group(group.parent, level_name)
-
-      reasons << errors[:reason]
-      instructions << errors[:instruction]
-    end
-
-    reasons = reasons.any? ? ' because ' + reasons.to_sentence : ''
-    "This group cannot be #{level_name}#{reasons}.#{instructions.join}".html_safe
-  end
-
   def visibility_icon_description(form_model)
     if form_model.respond_to?(:visibility_level_allowed_as_fork?)
       project_visibility_icon_description(form_model.visibility_level)
@@ -104,14 +34,6 @@ module VisibilityLevelHelper
     end
   end
 
-  def group_visibility_icon_description(level)
-    "#{visibility_level_label(level)} - #{group_visibility_level_description(level)}"
-  end
-
-  def project_visibility_icon_description(level)
-    "#{visibility_level_label(level)} - #{project_visibility_level_description(level)}"
-  end
-
   def visibility_level_label(level)
     # The visibility level can be:
     # 'VisibilityLevel|Private', 'VisibilityLevel|Internal', 'VisibilityLevel|Public'
@@ -203,11 +125,33 @@ module VisibilityLevelHelper
     current_level
   end
 
-  def visibility_level_errors_for_group(group, level_name)
-    group_name = link_to group.name, group_path(group)
-    change_visibility = link_to 'change the visibility', edit_group_path(group)
+  def project_visibility_level_description(level)
+    case level
+    when Gitlab::VisibilityLevel::PRIVATE
+      _("Project access must be granted explicitly to each user. If this project is part of a group, access will be granted to members of the group.")
+    when Gitlab::VisibilityLevel::INTERNAL
+      _("The project can be accessed by any logged in user except external users.")
+    when Gitlab::VisibilityLevel::PUBLIC
+      _("The project can be accessed without any authentication.")
+    end
+  end
+
+  def group_visibility_level_description(level)
+    case level
+    when Gitlab::VisibilityLevel::PRIVATE
+      _("The group and its projects can only be viewed by members.")
+    when Gitlab::VisibilityLevel::INTERNAL
+      _("The group and any internal projects can be viewed by any logged in user except external users.")
+    when Gitlab::VisibilityLevel::PUBLIC
+      _("The group and any public projects can be viewed without any authentication.")
+    end
+  end
 
-    { reason: "the visibility of #{group_name} is #{group.visibility}",
-      instruction: " To make this group #{level_name}, you must first #{change_visibility} of the parent group." }
+  def project_visibility_icon_description(level)
+    "#{visibility_level_label(level)} - #{project_visibility_level_description(level)}"
+  end
+
+  def group_visibility_icon_description(level)
+    "#{visibility_level_label(level)} - #{group_visibility_level_description(level)}"
   end
 end

spec/helpers/visibility_level_helper_spec.rb

@@ -35,29 +35,33 @@ RSpec.describe VisibilityLevelHelper do
 
   describe 'visibility_level_description' do
     context 'used with a Project' do
-      it 'delegates projects to #project_visibility_level_description' do
-        expect(visibility_level_description(Gitlab::VisibilityLevel::PRIVATE, project))
-            .to match /project/i
+      let(:descriptions) do
+        [
+          visibility_level_description(Gitlab::VisibilityLevel::PRIVATE, project),
+          visibility_level_description(Gitlab::VisibilityLevel::INTERNAL, project),
+          visibility_level_description(Gitlab::VisibilityLevel::PUBLIC, project)
+        ]
       end
-    end
 
-    context 'used with a Group' do
-      it 'delegates groups to #group_visibility_level_description' do
-        expect(visibility_level_description(Gitlab::VisibilityLevel::PRIVATE, group))
-            .to match /group/i
+      it 'returns different project related descriptions depending on visibility level' do
+        expect(descriptions.uniq.size).to eq(descriptions.size)
+        expect(descriptions).to all match /project/i
       end
     end
-  end
 
-  describe "#project_visibility_level_description" do
-    it "describes private projects" do
-      expect(project_visibility_level_description(Gitlab::VisibilityLevel::PRIVATE))
-            .to eq _('Project access must be granted explicitly to each user. If this project is part of a group, access will be granted to members of the group.')
-    end
+    context 'used with a Group' do
+      let(:descriptions) do
+        [
+          visibility_level_description(Gitlab::VisibilityLevel::PRIVATE, group),
+          visibility_level_description(Gitlab::VisibilityLevel::INTERNAL, group),
+          visibility_level_description(Gitlab::VisibilityLevel::PUBLIC, group)
+        ]
+      end
 
-    it "describes public projects" do
-      expect(project_visibility_level_description(Gitlab::VisibilityLevel::PUBLIC))
-            .to eq _('The project can be accessed without any authentication.')
+      it 'returns different group related descriptions depending on visibility level' do
+        expect(descriptions.uniq.size).to eq(descriptions.size)
+        expect(descriptions).to all match /group/i
+      end
     end
   end