Merge pull request #3498 from CocoaPods/mr-fix-download-cache

[Cache] Fix the cache to handle re-downloads properly

CHANGELOG.md

@@ -8,6 +8,11 @@ To install release candidates run `[sudo] gem install cocoapods --pre`
 
 ##### Bug Fixes
 
+* [Cache] Fixes a bug that caused that a pod, which was cached once is not updated
+  correctly when needed e.g. for `pod spec lint`.  
+  [Marius Rackwitz](https://github.com/mrackwitz)
+  [#3498](https://github.com/CocoaPods/CocoaPods/issues/3498)
+
 * Only add the "Embed Pods Frameworks" script for application and unit test targets.  
   [Marius Rackwitz](https://github.com/mrackwitz)
   [#3440](https://github.com/CocoaPods/CocoaPods/issues/3440)

lib/cocoapods/downloader/cache.rb

@@ -184,6 +184,7 @@ module Pod
       def copy_and_clean(source, destination, spec)
         specs_by_platform = group_subspecs_by_platform(spec)
         destination.parent.mkpath
+        FileUtils.rm_rf(destination)
         FileUtils.cp_r(source, destination)
         Pod::Installer::PodSourcePreparer.new(spec, destination).prepare!
         Sandbox::PodDirCleaner.new(destination, specs_by_platform).clean!