Merge branch...

Merge branch '54011-all-files-named-index-have-their-content-rendered-as-if-they-were-text-files' into 'master'

Resolve "All files named `index.*` have their content rendered as if they were text files"

Closes #54011

See merge request gitlab-org/gitlab-ce!23063

lib/gitlab/file_detector.rb

@@ -8,7 +8,7 @@ module Gitlab
   module FileDetector
     PATTERNS = {
       # Project files
-      readme: %r{\A(readme|index)[^/]*\z}i,
+      readme: /\A(#{Regexp.union(*Gitlab::MarkupHelper::PLAIN_FILENAMES).source})(\.(#{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/lib/gitlab/file_detector_spec.rb

@@ -15,14 +15,22 @@ describe Gitlab::FileDetector do
   describe '.type_of' do
     it 'returns the type of a README file' do
-      %w[README readme INDEX index].each do |filename|
+      filenames = Gitlab::MarkupHelper::PLAIN_FILENAMES + Gitlab::MarkupHelper::PLAIN_FILENAMES.map(&:upcase)
+      extensions = Gitlab::MarkupHelper::EXTENSIONS + Gitlab::MarkupHelper::EXTENSIONS.map(&:upcase)
+
+      filenames.each do |filename|
         expect(described_class.type_of(filename)).to eq(:readme)
-        %w[.md .adoc .rst].each do |extname|
-          expect(described_class.type_of(filename + extname)).to eq(:readme)
+
+        extensions.each do |extname|
+          expect(described_class.type_of("#{filename}.#{extname}")).to eq(:readme)
         end
       end
     end
+    it 'returns nil for a README.rb file' do
+      expect(described_class.type_of('README.rb')).to be_nil
+    end
+
     it 'returns nil for a README file in a directory' do
       expect(described_class.type_of('foo/README.md')).to be_nil
     end