Merge pull request #3713 from CocoaPods/seg-resolver-platform

[Resolver] Take supported platforms into account when resolving

CHANGELOG.md

@@ -4,6 +4,16 @@ To install or update CocoaPods see this [guide](http://docs.cocoapods.org/guides
 
 To install release candidates run `[sudo] gem install cocoapods --pre`
 
+## Master
+
+##### Enhancements
+
+* The resolver will now take supported platform deployment targets into account
+  when resolving dependencies.  
+  [Samuel Giddins](https://github.com/segiddins)
+  [#2443](https://github.com/CocoaPods/CocoaPods/issues/2443)
+
+
 ## 0.38.0.beta.1
 
 ##### Highlighted Enhancement That Needs Testing

lib/cocoapods/resolver.rb

@@ -37,6 +37,7 @@ module Pod
       @podfile = podfile
       @locked_dependencies = locked_dependencies
       @sources = Array(sources)
+      @platforms_by_dependency = Hash.new { |h, k| h[k] = [] }
     end
 
     #-------------------------------------------------------------------------#
@@ -52,7 +53,11 @@ module Pod
     #         definition.
     #
     def resolve
-      dependencies = podfile.target_definition_list.map(&:dependencies).flatten
+      dependencies = podfile.target_definition_list.flat_map do |target|
+        target.dependencies.each do |dep|
+          @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|
@@ -181,7 +186,7 @@ module Pod
       requirement_satisfied && !(
         spec.version.prerelease? &&
         existing_vertices.flat_map(&:requirements).none? { |r| r.prerelease? || r.external_source || r.head? }
-      )
+      ) && spec_is_platform_compatible?(activated, requirement, spec)
     end
 
     # Sort dependencies so that the ones that are easiest to resolve are first.
@@ -395,6 +400,31 @@ module Pod
       raise Informative, error.message
     end
 
+    # Returns whether the given spec is platform-compatible with the dependency
+    # graph, taking into account the dependency that has required the spec.
+    #
+    # @param  [Molinillo::DependencyGraph] dependency_graph
+    #
+    # @param  [Dependency] dependency
+    #
+    # @param  [Specification] specification
+    #
+    # @return [Bool]
+    def spec_is_platform_compatible?(dependency_graph, dependency, spec)
+      all_predecessors = ->(vertex) do
+        pred = vertex.predecessors
+        pred + pred.map(&all_predecessors).reduce(Set.new, &:&) << vertex
+      end
+      vertex = dependency_graph.vertex_named(dependency.name)
+      predecessors = all_predecessors[vertex].reject { |v| v.explicit_requirements.empty? }
+      platforms_to_satisfy = predecessors.flat_map(&:explicit_requirements).flat_map { |r| @platforms_by_dependency[r] }
+
+      platforms_to_satisfy.all? do |platform_to_satisfy|
+        spec.available_platforms.select { |spec_platform| spec_platform.name == platform_to_satisfy.name }.
+          all? { |spec_platform| platform_to_satisfy.supports?(spec_platform) }
+      end
+    end
+
     # Returns the target-appropriate nodes that are `successors` of `node`,
     # rejecting those that are scoped by target platform and have incompatible
     # targets.

spec/unit/installer/analyzer_spec.rb

@@ -328,12 +328,6 @@ module Pod
         ]
       end
 
-      it 'warns once any of the dependencies does not match the platform of its podfile target' do
-        Specification.any_instance.stubs(:available_platforms).returns([Platform.new(:ios, '999')])
-        @analyzer.analyze
-        UI.warnings.should.match(/platform .* may not be compatible/)
-      end
-
       xit 'removes the specifications of the changed pods to prevent confusion in the resolution process' do
         @analyzer.allow_pre_downloads = true
         podspec = @analyzer.sandbox.root + 'Local Podspecs/JSONKit.podspec'

spec/unit/resolver_spec.rb

@@ -180,6 +180,17 @@ module Pod
         end.message.should.match /platform .* not compatible/
       end
 
+      it 'selects only platform-compatible versions' do
+        @podfile = Podfile.new do
+          platform :osx, '10.7'
+          pod 'AFNetworking' # the most recent version requires 10.8
+        end
+        @resolver.stubs(:podfile).returns(@podfile)
+        @resolver.resolve.values.flatten.map(&:to_s).sort.should == [
+          'AFNetworking (1.3.4)',
+        ]
+      end
+
       it 'raises if unable to find a specification' do
         Specification.any_instance.stubs(:all_dependencies).returns([Dependency.new('Windows')])
         message = should.raise Informative do
@@ -340,7 +351,7 @@ module Pod
 
       it 'raises if it finds two conflicting dependencies' do
         podfile = Podfile.new do
-          platform :ios
+          platform :ios, '8.0'
           pod 'RestKit', '0.23.3' # dependends on AFNetworking ~> 1.3.0
           pod 'AFNetworking', '> 2'
         end