Merge pull request #2104 from CocoaPods/git-ff-only

[Sources] Use `git pull` with the `--ff-only` flag

CHANGELOG.md

@@ -54,6 +54,10 @@ To install or update CocoaPods see this [guide](http://docs.cocoapods.org/guides
   [Samuel E. Giddins](https://github.com/segiddins)
   [#2003](https://github.com/CocoaPods/CocoaPods/issues/2003)
 
+* Fixes an issue where `pod repo update` may start an un-committed merge.  
+  [Kyle Fuller][kylef]
+  [#2024](https://github.com/CocoaPods/CocoaPods/issues/2024)
+
 ## 0.32.1
 
 ##### Bug Fixes

lib/cocoapods/sources_manager.rb

@@ -153,7 +153,7 @@ module Pod
           UI.section "Updating spec repo `#{source.name}`" do
             Dir.chdir(source.data_provider.repo) do
               begin
-                output = git!("pull --no-rebase --no-commit")
+                output = git!("pull --ff-only")
                 UI.puts output if show_output && !config.verbose?
               rescue Informative => e
                 raise Informative, 'An error occurred while performing ' \

spec/unit/sources_manager_spec.rb

@@ -116,20 +116,13 @@ module Pod
         set_up_test_repo_for_update
 
         SourcesManager.update(test_repo_path.basename.to_s, true)
-        UI.output.should.match /Already up-to-date/
+        UI.output.should.match /is up to date/
       end
 
-      it "is robust against user settings for git repos" do
+      it "uses the only fast forward git option" do
         set_up_test_repo_for_update
 
-        SourcesManager.expects(:git!).with() { |options| options.should.match /--no-rebase/ }
-        SourcesManager.update(test_repo_path.basename.to_s, true)
-      end
-
-      it "doesn't allow merge commits" do
-        set_up_test_repo_for_update
-
-        SourcesManager.expects(:git!).with() { |options| options.should.match /--no-commit/ }
+        SourcesManager.expects(:git!).with() { |options| options.should.match /--ff-only/ }
         SourcesManager.update(test_repo_path.basename.to_s, true)
       end