Fixing bug related to wiki last version

Gemfile

@@ -70,6 +70,10 @@ gem 'net-ldap'
 # Git Wiki
 # Required manually in config/initializers/gollum.rb to control load order
 gem 'gollum-lib', '~> 4.2', require: false
+
+# Before updating this gem, check if
+# https://github.com/gollum/rugged_adapter/pull/28 has been merged.
+# If it has, then remove the monkey patch for tree_entry in config/initializers/gollum.rb
 gem 'gollum-rugged_adapter', '~> 0.4.4', require: false
 
 # Language detection

changelogs/unreleased/fj-41477-fix-bug-wiki-last-version.yml

+---
+title: Fixing bug when wiki last version
+merge_request: 16197
+author:
+type: fixed

config/initializers/gollum.rb

@@ -36,6 +36,26 @@ module Gollum
       end
     end
   end
+
+  module Git
+    class Git
+      def tree_entry(commit, path)
+        pathname = Pathname.new(path)
+        tmp_entry = nil
+
+        pathname.each_filename do |dir|
+          tmp_entry = if tmp_entry.nil?
+                        commit.tree[dir]
+                      else
+                        @repo.lookup(tmp_entry[:oid])[dir]
+                      end
+
+          return nil unless tmp_entry
+        end
+        tmp_entry
+      end
+    end
+  end
 end
 
 Rails.application.configure do

spec/initializers/gollum_spec.rb

+require 'spec_helper'
+
+describe 'gollum' do
+  let(:project) { create(:project) }
+  let(:user) { project.owner }
+  let(:wiki) { ProjectWiki.new(project, user) }
+  let(:gollum_wiki) { Gollum::Wiki.new(wiki.repository.path) }
+
+  before do
+    create_page(page_name, 'content1')
+  end
+
+  after do
+    destroy_page(page_name)
+  end
+
+  context 'with simple paths' do
+    let(:page_name) { 'page1' }
+
+    it 'returns the entry hash if it matches the file name' do
+      expect(tree_entry(page_name)).not_to be_nil
+    end
+
+    it 'returns nil if the path does not fit completely' do
+      expect(tree_entry("foo/#{page_name}")).to be_nil
+    end
+  end
+
+  context 'with complex paths' do
+    let(:page_name) { '/foo/bar/page2' }
+
+    it 'returns the entry hash if it matches the file name' do
+      expect(tree_entry(page_name)).not_to be_nil
+    end
+
+    it 'returns nil if the path does not fit completely' do
+      expect(tree_entry("foo1/bar/page2")).to be_nil
+      expect(tree_entry("foo/bar1/page2")).to be_nil
+    end
+  end
+
+  def tree_entry(name)
+    gollum_wiki.repo.git.tree_entry(wiki_commits[0].commit, name + '.md')
+  end
+
+  def wiki_commits
+    gollum_wiki.repo.commits
+  end
+
+  def commit_details
+    Gitlab::Git::Wiki::CommitDetails.new(user.name, user.email, "test commit")
+  end
+
+  def create_page(name, content)
+    wiki.wiki.write_page(name, :markdown, content, commit_details)
+  end
+
+  def destroy_page(name)
+    page = wiki.find_page(name).page
+    wiki.delete_page(page, "test commit")
+  end
+end