Show READMEs with .txt extension

There are two categories of README files: markup and plain text. For some
reason, READMEs with .txt extension disappeared from the plain text category,
leaving there only READMEs without extension. This MR returns .txt READMEs into
the plain text category so that they are again recognized as README files and
rendered on a project page.

app/assets/javascripts/repository/utils/readme.js

@@ -24,7 +24,7 @@ const isRichReadme = file => {
 };
 
 const isPlainReadme = file => {
-  const re = new RegExp(`^(${FILENAMES.join('|')})$`, 'i');
+  const re = new RegExp(`^(${FILENAMES.join('|')})(\\.txt)?$`, 'i');
   return re.test(file.name);
 };
 

changelogs/unreleased/25343-show-readme-txt.yml

+---
+title: Fix README.txt not showing up on a project page
+merge_request: 21763
+author: Alexander Oleynikov
+type: fixed

lib/gitlab/file_detector.rb

@@ -8,7 +8,7 @@ module Gitlab
   module FileDetector
     PATTERNS = {
       # Project files
-      readme: /\A(#{Regexp.union(*Gitlab::MarkupHelper::PLAIN_FILENAMES).source})(\.(#{Regexp.union(*Gitlab::MarkupHelper::EXTENSIONS).source}))?\z/i,
+      readme: /\A(#{Regexp.union(*Gitlab::MarkupHelper::PLAIN_FILENAMES).source})(\.(txt|#{Regexp.union(*Gitlab::MarkupHelper::EXTENSIONS).source}))?\z/i,
       changelog: %r{\A(changelog|history|changes|news)[^/]*\z}i,
       license: %r{\A((un)?licen[sc]e|copying)(\.[^/]+)?\z}i,
       contributing: %r{\Acontributing[^/]*\z}i,

spec/frontend/repository/utils/readme_spec.js

@@ -31,6 +31,12 @@ describe('readmeFile', () => {
     });
   });
 
+  it('recognizes Readme.txt as a plain text README', () => {
+    expect(readmeFile([{ name: 'Readme.txt' }])).toEqual({
+      name: 'Readme.txt',
+    });
+  });
+
   it('returns undefined when there are no appropriate files', () => {
     expect(readmeFile([{ name: 'index.js' }, { name: 'md.README' }])).toBe(undefined);
     expect(readmeFile([])).toBe(undefined);

spec/helpers/markup_helper_spec.rb

@@ -410,7 +410,7 @@ describe MarkupHelper do
     end
 
     context 'when file has an unknown type' do
-      let(:file_name) { 'foo' }
+      let(:file_name) { 'foo.tex' }
 
       it 'returns html (rendered by Gitlab::OtherMarkup)' do
         expected_html = 'Noël'

spec/lib/gitlab/file_detector_spec.rb

@@ -16,23 +16,30 @@ describe Gitlab::FileDetector do
   end
 
   describe '.type_of' do
-    it 'returns the type of a README file' do
-      filenames = Gitlab::MarkupHelper::PLAIN_FILENAMES + Gitlab::MarkupHelper::PLAIN_FILENAMES.map(&:upcase)
-      extensions = Gitlab::MarkupHelper::EXTENSIONS + Gitlab::MarkupHelper::EXTENSIONS.map(&:upcase)
+    it 'returns the type of a README without extension' do
+      expect(described_class.type_of('README')).to eq(:readme)
+      expect(described_class.type_of('INDEX')).to eq(:readme)
+    end
 
-      filenames.each do |filename|
-        expect(described_class.type_of(filename)).to eq(:readme)
+    it 'returns the type of a README file with a recognized extension' do
+      extensions = ['txt', *Gitlab::MarkupHelper::EXTENSIONS]
 
-        extensions.each do |extname|
-          expect(described_class.type_of("#{filename}.#{extname}")).to eq(:readme)
+      extensions.each do |ext|
+        %w(index readme).each do |file|
+          expect(described_class.type_of("#{file}.#{ext}")).to eq(:readme)
         end
       end
     end
 
-    it 'returns nil for a README.rb file' do
+    it 'returns nil for a README with unrecognized extension' do
       expect(described_class.type_of('README.rb')).to be_nil
     end
 
+    it 'is case insensitive' do
+      expect(described_class.type_of('ReadMe')).to eq(:readme)
+      expect(described_class.type_of('index.TXT')).to eq(:readme)
+    end
+
     it 'returns nil for a README file in a directory' do
       expect(described_class.type_of('foo/README.md')).to be_nil
     end