[Git] Use for the cache.

CHANGELOG.md

@@ -9,6 +9,11 @@
 - Support for `header_mappings_dir` attribute in subspecs.
 - Refactored UI.
 
+###### Bug fixes
+
+- Improvements to the git cache that should be more robust.
+  [#517](https://github.com/CocoaPods/CocoaPods/issues/517)
+
 ## Master
 
 [CocoaPods](https://github.com/CocoaPods/CocoaPods/compare/0.14.0...master)

lib/cocoapods/downloader/git.rb

@@ -34,7 +34,7 @@ module Pod
         ui_title " > Creating cache git repo (#{cache_path})"
         cache_path.rmtree if cache_path.exist?
         cache_path.mkpath
-        clone(url, cache_path)
+        git! %Q|clone  --mirror "#{url}" "#{cache_path}"|
       end
 
       def prune_cache
@@ -77,12 +77,16 @@ module Pod
       def update_cache
         ui_title " > Updating cache git repo (#{cache_path})"
         Dir.chdir(cache_path) do
+          if git("config core.bare").chomp == "true"
+            git! "remote update"
+          else
             git! "reset --hard HEAD"
             git! "clean -d -x -f"
             git! "pull origin master"
             git! "fetch --tags"
           end
         end
+      end
 
       def ref_exists?(ref)
         Dir.chdir(cache_path) { git "rev-list --max-count=1 #{ref}" }