Maintain a versions.json file tracking the latest per series

lib/docs_generator.rb

@@ -1,5 +1,6 @@
 require 'set'
 require 'logging'
+require 'json'
 require 'docs_compressor'
 require 'git_manager'
 
@@ -86,7 +87,10 @@ def generate_stable_docs
       end
     end
 
-    adjust_symlinks_for_series if new_stable_docs
+    if new_stable_docs
+      adjust_symlinks_for_series
+      adjust_json_for_series
+    end
   end
 
   def generate_stable_docs_for?(tag)
@@ -163,6 +167,29 @@ def adjust_symlinks_for_series
     end
   end
 
+  def adjust_json_for_series
+    entries = series.map { |series, tag|
+      next if series == STABLE
+      { series: series.delete('v'), version: tag.delete('v'), date: git_manager.tag_date(tag) }
+    }.compact.sort { |a, b| compare_tags(b[:version], a[:version]) }
+
+    json_content = JSON.dump(entries)
+    js_content = 'currentRailsVersions(' + json_content + ');'
+
+    [API, GUIDES].each do |_|
+      Dir.chdir(_) do
+        ensure_file 'versions.json', json_content
+        ensure_file 'versions.js', js_content
+      end
+    end
+  end
+
+  def ensure_file(filename, content)
+    unless File.exist?(filename) && File.read(filename) == content
+      File.open(filename, 'w') { |f| f.write(content) }
+    end
+  end
+
   def series
     sds = stable_directories
 

lib/git_manager.rb

@@ -51,6 +51,12 @@ def release_tags
     end
   end
 
+  def tag_date(tag)
+    Dir.chdir("#{basedir}/master") do
+      `git for-each-ref --format="%(taggerdate:iso8601)" refs/tags/#{tag}`.chomp
+    end
+  end
+
   def short_sha1
     sha1[0, 7]
   end

test/test_docs_generator.rb

@@ -32,6 +32,31 @@ def test_series
     end
   end
 
+  def test_version_json
+    stable_directories = %w(v3.1.2 v3.1.0 v4.2.1 v4.2.7 v5.0.0)
+    expected = '[{"series":"5.0","version":"5.0.0","date":"2000-01-01 01:12:23 +0100"},'\
+                '{"series":"4.2","version":"4.2.7","date":"2000-01-01 01:12:23 +0100"},'\
+                '{"series":"3.1","version":"3.1.2","date":"2000-01-01 01:12:23 +0100"}]'
+
+    in_tmpdir do
+      mkdir 'basedir'
+      mkdir 'api'
+      mkdir 'guides'
+
+      Dir.chdir('basedir') do
+        stable_directories.each {|sd| mkdir sd}
+      end
+
+      git_manager = GitManager.new('basedir')
+
+      git_manager.stub(:tag_date, '2000-01-01 01:12:23 +0100') do
+        DocsGenerator.new('basedir', git_manager).adjust_json_for_series
+      end
+
+      assert_equal expected, File.read('api/versions.json')
+    end
+  end
+
   def test_stable_directories
     stable_directories = %w(v4.0.1 v4.1.7 v4.11.2 v3.1.2)
 

test/test_git_manager.rb

@@ -52,6 +52,24 @@ def test_release_tags
     end
   end
 
+  def test_tag_date
+    in_tmpdir do
+      mkdir_p 'basedir/master'
+
+      chdir 'basedir/master' do
+        create_repository
+        %w(0.9.4.1 2.3.9.pre 3.0.0_RC2 3.2.8.rc1 3.2.14 v4.0.0.beta1 4.0.1).each_with_index do |version, idx|
+          system "GIT_COMMITTER_DATE='2000-01-#{10 + idx} 01:23:45 -0200' git tag -a -m 'Release' v#{version}"
+        end
+      end
+
+      git_manager = GitManager.new('basedir')
+      assert_equal '2000-01-10 01:23:45 -0200', git_manager.tag_date('v0.9.4.1')
+      assert_equal '2000-01-14 01:23:45 -0200', git_manager.tag_date('v3.2.14')
+      assert_equal '2000-01-16 01:23:45 -0200', git_manager.tag_date('v4.0.1')
+    end
+  end
+
   def test_sha1_and_short_sha1
     in_tmpdir do
       mkdir_p 'basedir/master'