Displays the previous version of the gem when run bundle update

Change code in the 3 source files to display the method locked_gems in
lib/bundler.rb

Add 3 Rspec test in the update directory for each source: rubygems, git,
path.

1 files changed, 5 insertions, 2 deletions

diff --git a/lib/bundler.rb b/lib/bundler.rb
index f6e75dd7c0..311409bdfc 100644
--- a/lib/bundler.rb
+++ b/lib/bundler.rb
@@ -153,9 +153,12 @@ module Bundler
     end
 
     def locked_gems
-      @locked_gems ||= begin
+      return @locked_gems if defined?(@locked_gems)
+      if Bundler.default_lockfile.exist?
         lock = Bundler.read_file(Bundler.default_lockfile)
-        LockfileParser.new(lock)
+        @lock_gems = LockfileParser.new(lock)
+      else
+        @locked_gems = nil
       end
     end