Correctly count wiki pages in sidebar

The existing code had two problems:

- We were only counting toplevel entries, not individual pages.
- We were showing the "View All Pages" button when the number of pages
  exactly matches the limit, even when there are no further pages.

This is now resolved by loading one page more than the limit, and using
the result count to determine if we have more pages.

app/controllers/projects/wikis_controller.rb

@@ -145,7 +145,7 @@ class Projects::WikisController < Projects::ApplicationController
     @sidebar_page = @project_wiki.find_sidebar(params[:version_id])
 
     unless @sidebar_page # Fallback to default sidebar
-      @sidebar_wiki_entries = WikiPage.group_by_directory(@project_wiki.list_pages(limit: 15))
+      @sidebar_wiki_entries, @sidebar_limited = @project_wiki.sidebar_entries
     end
   rescue ProjectWiki::CouldNotCreateWikiError
     flash[:notice] = _("Could not create Wiki Repository at this time. Please try again later.")

app/models/wiki.rb

@@ -93,6 +93,14 @@ class Wiki
     end
   end
 
+  def sidebar_entries(limit: Gitlab::WikiPages::MAX_SIDEBAR_PAGES, **options)
+    pages = list_pages(**options.merge(limit: limit + 1))
+    limited = pages.size > limit
+    pages = pages.first(limit) if limited
+
+    [WikiPage.group_by_directory(pages), limited]
+  end
+
   # Finds a page within the repository based on a tile
   # or slug.
   #

app/views/projects/wikis/_sidebar.html.haml

@@ -17,6 +17,6 @@
           %ul.wiki-pages
             = render @sidebar_wiki_entries, context: 'sidebar'
       .block.w-100
-        - if @sidebar_wiki_entries&.length.to_i >= 15
+        - if @sidebar_limited
           = link_to project_wikis_pages_path(@project), class: 'btn btn-block' do
             = s_("Wiki|View All Pages")

changelogs/unreleased/correctly-count-wiki-pages-in-sidebar.yml

+---
+title: Correctly count wiki pages in sidebar
+merge_request: 30508
+author:
+type: fixed

lib/gitlab/wiki_pages.rb

@@ -11,5 +11,8 @@ module Gitlab
     # through the GitLab web interface and API:
     MAX_TITLE_BYTES = 245 # reserving 10 bytes for the file extension
     MAX_DIRECTORY_BYTES = 255
+
+    # Limit the number of pages displayed in the wiki sidebar.
+    MAX_SIDEBAR_PAGES = 15
   end
 end

spec/controllers/projects/wikis_controller_spec.rb

@@ -98,13 +98,12 @@ describe Projects::WikisController do
       let(:id) { wiki_title }
 
       it 'limits the retrieved pages for the sidebar' do
-        expect(controller).to receive(:load_wiki).and_return(project_wiki)
-        expect(project_wiki).to receive(:list_pages).with(limit: 15).and_call_original
-
         subject
 
         expect(response).to have_gitlab_http_status(:ok)
         expect(assigns(:page).title).to eq(wiki_title)
+        expect(assigns(:sidebar_wiki_entries)).to contain_exactly(an_instance_of(WikiPage))
+        expect(assigns(:sidebar_limited)).to be(false)
       end
 
       context 'when page content encoding is invalid' do

spec/features/projects/wiki/user_creates_wiki_page_spec.rb

@@ -312,6 +312,7 @@ describe "User creates wiki page" do
         visit(project_wikis_path(project))
 
         expect(page).to have_content('another')
+        expect(page).not_to have_link('View All Pages')
       end
 
       context 'when there is a customized sidebar' do
@@ -328,17 +329,31 @@ describe "User creates wiki page" do
       end
     end
 
-    context 'when there are more than 15 existing pages' do
+    context 'when there are 15 existing pages' do
       before do
-        create(:wiki_page, wiki: wiki, title: 'home', content: 'home')
-        (1..14).each { |i| create(:wiki_page, wiki: wiki, title: "page-#{i}", content: "page #{i}") }
+        (1..5).each { |i| create(:wiki_page, wiki: wiki, title: "my page #{i}") }
+        (6..10).each { |i| create(:wiki_page, wiki: wiki, title: "parent/my page #{i}") }
+        (11..15).each { |i| create(:wiki_page, wiki: wiki, title: "grandparent/parent/my page #{i}") }
       end
 
-      it 'renders a default sidebar when there is no customized sidebar' do
+      it 'shows all pages in the sidebar' do
         visit(project_wikis_path(project))
 
-        expect(page).to have_content('View All Pages')
-        expect(page).to have_content('page 1')
+        (1..15).each { |i| expect(page).to have_content("my page #{i}") }
+        expect(page).not_to have_link('View All Pages')
+      end
+
+      context 'when there are more than 15 existing pages' do
+        before do
+          create(:wiki_page, wiki: wiki, title: 'my page 16')
+        end
+
+        it 'shows the first 15 pages in the sidebar' do
+          visit(project_wikis_path(project))
+
+          expect(page).to have_text('my page', count: 15)
+          expect(page).to have_link('View All Pages')
+        end
       end
     end
   end

spec/support/shared_examples/models/wiki_shared_examples.rb

@@ -148,6 +148,44 @@ RSpec.shared_examples 'wiki model' do
     end
   end
 
+  describe '#sidebar_entries' do
+    before do
+      (1..5).each { |i| create(:wiki_page, wiki: wiki, title: "my page #{i}") }
+      (6..10).each { |i| create(:wiki_page, wiki: wiki, title: "parent/my page #{i}") }
+      (11..15).each { |i| create(:wiki_page, wiki: wiki, title: "grandparent/parent/my page #{i}") }
+    end
+
+    def total_pages(entries)
+      entries.sum do |entry|
+        entry.is_a?(WikiDirectory) ? entry.pages.size : 1
+      end
+    end
+
+    context 'when the number of pages does not exceed the limit' do
+      it 'returns all pages grouped by directory and limited is false' do
+        entries, limited = subject.sidebar_entries
+
+        expect(entries.size).to be(7)
+        expect(total_pages(entries)).to be(15)
+        expect(limited).to be(false)
+      end
+    end
+
+    context 'when the number of pages exceeds the limit' do
+      before do
+        create(:wiki_page, wiki: wiki, title: 'my page 16')
+      end
+
+      it 'returns 15 pages grouped by directory and limited is true' do
+        entries, limited = subject.sidebar_entries
+
+        expect(entries.size).to be(8)
+        expect(total_pages(entries)).to be(15)
+        expect(limited).to be(true)
+      end
+    end
+  end
+
   describe '#find_page' do
     before do
       subject.create_page('index page', 'This is an awesome Gollum Wiki')