add `--paths` option to `bundle list` command.

This option mimics the `--paths` options in `bundle show` which is
being removed in bundler 2.

Example Usage:

  $ bundle list --paths
  /Users/c/Desktop/Projects/testapp/.bundle/ruby/2.4.0/gems/actioncable-5.1.4
  /Users/c/Desktop/Projects/testapp/.bundle/ruby/2.4.0/gems/actionmailer-5.1.4
  /Users/c/Desktop/Projects/testapp/.bundle/ruby/2.4.0/gems/actionpack-5.1.4
  /Users/c/Desktop/Projects/testapp/.bundle/ruby/2.4.0/gems/actionview-5.1.4

4 files changed, 19 insertions, 0 deletions

diff --git a/lib/bundler/cli.rb b/lib/bundler/cli.rb
index 7744a6f801..98c02fc791 100644
--- a/lib/bundler/cli.rb
+++ b/lib/bundler/cli.rb
@@ -285,6 +285,7 @@ module Bundler
     if Bundler.feature_flag.list_command?
       desc "list", "List all gems in the bundle"
       method_option "name-only", :type => :boolean, :banner => "print only the gem names"
+      method_option "paths", :type => :boolean, :banner => "print the path to each gem in the bundle"
       def list
         require "bundler/cli/list"
         List.new(options).run
diff --git a/lib/bundler/cli/list.rb b/lib/bundler/cli/list.rb
index b5e7c1e650..73f69a9eaf 100644
--- a/lib/bundler/cli/list.rb
+++ b/lib/bundler/cli/list.rb
@@ -9,6 +9,7 @@ module Bundler
     def run
       specs = Bundler.load.specs.reject {|s| s.name == "bundler" }.sort_by(&:name)
       return specs.each {|s| Bundler.ui.info s.name } if @options["name-only"]
+      return specs.each {|s| Bundler.ui.info s.full_gem_path } if @options["paths"]
 
       return Bundler.ui.info "No gems in the Gemfile" if specs.empty?
       Bundler.ui.info "Gems included by the bundle:"
diff --git a/man/bundle-list.ronn b/man/bundle-list.ronn
index 79fcfff701..b7a9d3f786 100644
--- a/man/bundle-list.ronn
+++ b/man/bundle-list.ronn
@@ -13,3 +13,5 @@ Prints a list of all the gems in the bundle including their version.
 
 * `--name-only`:
   Print only the name of each gem.
+* `--paths`:
+  Print the path to each gem in the bundle.
diff --git a/spec/commands/list_spec.rb b/spec/commands/list_spec.rb
index 0ea70f015c..7fb25963ec 100644
--- a/spec/commands/list_spec.rb
+++ b/spec/commands/list_spec.rb
@@ -15,6 +15,21 @@ RSpec.describe "bundle list", :bundler => "2" do
     end
   end
 
+  context "with paths option" do
+    before do
+      install_gemfile <<-G
+        source "file://#{gem_repo1}"
+        gem "rack"
+        gem "rails"
+      G
+    end
+    it "prints the path of each gem in the bundle" do
+      bundle "list --paths"
+      expect(out).to match(%r{.*\/rails\-2\.3\.2})
+      expect(out).to match(%r{.*\/rack\-1\.0\.0})
+    end
+  end
+
   context "when no gems are in the gemfile" do
     before do
       install_gemfile <<-G