Merge branch 'fix-viewing-wiki-page-lastest-version-via-version-id' into 'master'

Fix "old version" warning when viewing wiki page's latest version via version_id in URL

Fixes #12712

See merge request !2627

app/models/wiki_page.rb

@@ -110,7 +110,7 @@ class WikiPage
   # Returns boolean True or False if this instance
   # is an old version of the page.
   def historical?
-    @page.historical?
+    @page.historical? && versions.first.sha != version.sha
   end
   # Returns boolean True or False if this instance

spec/models/wiki_page_spec.rb

@@ -189,6 +189,38 @@ describe WikiPage, models: true do
     end
   end
+  describe '#historical?' do
+    before do
+      create_page('Update', 'content')
+      @page = wiki.find_page('Update')
+      3.times { |i| @page.update("content #{i}") }
+    end
+
+    after do
+      destroy_page('Update')
+    end
+
+    it 'returns true when requesting an old version' do
+      old_version = @page.versions.last.to_s
+      old_page = wiki.find_page('Update', old_version)
+
+      expect(old_page.historical?).to eq true
+    end
+
+    it 'returns false when requesting latest version' do
+      latest_version = @page.versions.first.to_s
+      latest_page = wiki.find_page('Update', latest_version)
+
+      expect(latest_page.historical?).to eq false
+    end
+
+    it 'returns false when version is nil' do
+      latest_page = wiki.find_page('Update', nil)
+
+      expect(latest_page.historical?).to eq false
+    end
+  end
+
   private
   def remove_temp_repo(path)