[Git] Refine tag downloads optimization

Gemfile.lock

@@ -1,36 +1,38 @@
 GEM
   remote: http://rubygems.org/
   specs:
-    addressable (2.3.3)
+    addressable (2.3.5)
     bacon (1.2.0)
     colorize (0.5.8)
-    coveralls (0.6.2)
+    coveralls (0.6.7)
       colorize
       multi_json (~> 1.3)
       rest-client
       simplecov (>= 0.7)
       thor
-    crack (0.3.2)
+    crack (0.4.1)
+      safe_yaml (~> 0.9.0)
     metaclass (0.0.1)
-    mime-types (1.21)
-    mocha (0.13.3)
+    mime-types (1.23)
+    mocha (0.14.0)
       metaclass (~> 0.0.1)
     mocha-on-bacon (0.2.2)
       mocha (>= 0.13.0)
-    multi_json (1.7.0)
-    rake (10.0.3)
+    multi_json (1.7.7)
+    rake (10.1.0)
     rest-client (1.6.7)
       mime-types (>= 1.16)
+    safe_yaml (0.9.4)
     simplecov (0.7.1)
       multi_json (~> 1.0)
       simplecov-html (~> 0.7.1)
     simplecov-html (0.7.1)
-    thor (0.17.0)
-    vcr (2.4.0)
+    thor (0.18.1)
+    vcr (2.5.0)
     webmock (1.8.11)
       addressable (>= 2.2.7)
       crack (>= 0.1.7)
-    yard (0.8.5.2)
+    yard (0.8.7)
 
 PLATFORMS
   ruby

lib/cocoapods-downloader/git.rb

@@ -77,22 +77,26 @@ def clone(from, to)
       # @note   Git fetch and checkout output to standard error and thus they
       #         are redirected to stdout.
       #
+      # @note   For performance if the cache is used the repo is inialized with
+      #         git clone (see CocoaPods/CocoaPods#1077).
+      #
       def download_tag
         if use_cache?
           if aggressive_cache?
             ensure_ref_exists(options[:tag])
           else
             update_cache
           end
-
-          git! "clone '#{clone_url}' '#{target_path}'"
         end
 
         Dir.chdir(target_path) do
-          if !use_cache?
+          if use_cache?
+            git! "clone '#{clone_url}' '#{target_path}'"
+          else
             git! "init"
             git! "remote add origin '#{clone_url}'"
           end
+
           git! "fetch origin tags/#{options[:tag]} 2>&1"
           git! "reset --hard FETCH_HEAD"
           git! "checkout -b activated-pod-commit 2>&1"

spec/cocoapods-downloaders/git_spec.rb

@@ -29,6 +29,19 @@ module Downloader
         tmp_folder('README').read.strip.should == 'v1.0'
       end
 
+      it "checks out a specific tag using git clone when a cache is available for performance" do
+        options = { :git => fixture('git-repo'), :tag => 'v1.0' }
+        downloader = Downloader.for_target(tmp_folder('destination'), options)
+        downloader.cache_root = tmp_folder('cache')
+        def downloader.execute_command(executable, command, raise_on_failure = false)
+          @spec_commands_log ||= []
+          @spec_commands_log << command
+        end
+        downloader.download
+        commands = downloader.instance_variable_get("@spec_commands_log").join("\n")
+        commands.should.not.include("init")
+      end
+
       it "doesn't updates submodules by default" do
         options = { :git => fixture('git-repo'), :commit => 'd7f4104' }
         downloader = Downloader.for_target(tmp_folder, options)