generate gems.rb in bundle init with feature flag

4 files changed, 19 insertions, 6 deletions

diff --git a/lib/bundler/cli/init.rb b/lib/bundler/cli/init.rb
index 8ffd1db41a..ae5d68853e 100644
--- a/lib/bundler/cli/init.rb
+++ b/lib/bundler/cli/init.rb
@@ -7,8 +7,8 @@ module Bundler
     end
 
     def run
-      if File.exist?("Gemfile")
-        Bundler.ui.error "Gemfile already exists at #{SharedHelpers.pwd}/Gemfile"
+      if File.exist?(gemfile)
+        Bundler.ui.error "#{gemfile} already exists at #{SharedHelpers.pwd}/#{gemfile}"
         exit 1
       end
 
@@ -21,15 +21,21 @@ module Bundler
 
         spec = Bundler.load_gemspec_uncached(gemspec)
 
-        puts "Writing new Gemfile to #{SharedHelpers.pwd}/Gemfile"
-        File.open("Gemfile", "wb") do |file|
+        puts "Writing new Gemfile to #{SharedHelpers.pwd}/#{gemfile}"
+        File.open(gemfile, "wb") do |file|
           file << "# Generated from #{gemspec}\n"
           file << spec.to_gemfile
         end
       else
-        puts "Writing new Gemfile to #{SharedHelpers.pwd}/Gemfile"
-        FileUtils.cp(File.expand_path("../../templates/Gemfile", __FILE__), "Gemfile")
+        puts "Writing new #{gemfile} to #{SharedHelpers.pwd}/#{gemfile}"
+        FileUtils.cp(File.expand_path("../../templates/#{gemfile}", __FILE__), gemfile)
       end
     end
+
+  private
+
+    def gemfile
+      @gemfile ||= Bundler.feature_flag.new_gemfile_name? ? "gems.rb" : "Gemfile"
+    end
   end
 end
diff --git a/lib/bundler/feature_flag.rb b/lib/bundler/feature_flag.rb
index 5ee69f538c..a75bcfb5f7 100644
--- a/lib/bundler/feature_flag.rb
+++ b/lib/bundler/feature_flag.rb
@@ -18,6 +18,7 @@ module Bundler
     settings_flag(:only_update_to_newer_versions) { bundler_2_mode? }
     settings_flag(:plugins) { @bundler_version >= Gem::Version.new("1.14") }
     settings_flag(:error_on_stderr) { bundler_2_mode? }
+    settings_flag(:new_gemfile_name) { bundler_2_mode? }
 
     def initialize(bundler_version)
       @bundler_version = Gem::Version.create(bundler_version)
diff --git a/lib/bundler/settings.rb b/lib/bundler/settings.rb
index 68a7add942..d5927afd87 100644
--- a/lib/bundler/settings.rb
+++ b/lib/bundler/settings.rb
@@ -28,6 +28,7 @@ module Bundler
       plugins
       silence_root_warning
       error_on_stderr
+      new_gemfile_name
     ].freeze
 
     NUMBER_KEYS = %w[
diff --git a/lib/bundler/templates/gems.rb b/lib/bundler/templates/gems.rb
new file mode 100644
index 0000000000..a6ef23ba3e
--- /dev/null
+++ b/lib/bundler/templates/gems.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+# A sample gems.rb
+source "https://rubygems.org"
+
+# gems "rails"