[Resolver] Add spec for platform compatibility of transitive deps

lib/cocoapods/resolver.rb

@@ -38,6 +38,7 @@ module Pod
       @locked_dependencies = locked_dependencies
       @sources = Array(sources)
       @platforms_by_dependency = Hash.new { |h, k| h[k] = [] }
+      @cached_sets = {}
     end
 
     #-------------------------------------------------------------------------#
@@ -58,7 +59,6 @@ module Pod
           @platforms_by_dependency[dep].push(target.platform).uniq!
         end
       end
-      @cached_sets = {}
       @activated = Molinillo::Resolver.new(self, self).resolve(dependencies, locked_dependencies)
       specs_by_target.tap do |specs_by_target|
         specs_by_target.values.flatten.each do |spec|

spec/unit/resolver_spec.rb

@@ -191,6 +191,30 @@ module Pod
         ]
       end
 
+      it 'selects only platform-compatible versions for transitive dependencies' do
+        spec = Pod::Spec.new do |s|
+          s.name = 'lib'
+          s.version = '1.0'
+          s.platform = :ios, '5.0'
+          s.subspec('Calendar') {}
+          s.subspec('Classes') { |ss| ss.dependency 'lib/Calendar' }
+          s.subspec('RequestManager') do |ss|
+            ss.dependency 'lib/Classes'
+            ss.dependency 'AFNetworking'
+          end
+          s.default_subspec = 'RequestManager'
+        end
+        @podfile = Podfile.new do
+          platform :ios, '5.0'
+          pod 'lib'
+        end
+        @resolver.stubs(:podfile).returns(@podfile)
+        @resolver.send(:cached_sets)['lib'] = stub(:all_specifications => [spec])
+        @resolver.resolve.values.flatten.map(&:to_s).sort.should == [
+          'AFNetworking (1.3.4)', 'lib (1.0)', 'lib/Calendar (1.0)', 'lib/Classes (1.0)', 'lib/RequestManager (1.0)'
+        ]
+      end
+
       it 'raises an informative error when version conflicts are caused by platform incompatibilities' do
         @podfile = Podfile.new do
           platform :osx, '10.7'