Allow sub folders under target framework folders

src/Packaging/PackageReaderBase.cs

@@ -193,10 +193,11 @@ protected IEnumerable<FrameworkSpecificGroup> GetFileGroups(string folder)
             Dictionary<NuGetFramework, List<string>> groups = new Dictionary<NuGetFramework, List<string>>(new NuGetFrameworkFullComparer());
 
             bool isContentFolder = StringComparer.OrdinalIgnoreCase.Equals(folder, PackagingConstants.ContentFolder);
+            bool allowSubFolders = true;
 
             foreach (string path in GetFiles(folder))
             {
-                NuGetFramework framework = NuGetFramework.Parse(GetFrameworkFromPath(path, isContentFolder));
+                NuGetFramework framework = NuGetFramework.Parse(GetFrameworkFromPath(path, allowSubFolders));
 
                 // Content allows both random folder names and framework folder names.
                 // It's nearly impossible to tell the difference and stay consistent over

test/Packaging.Test/PackageReaderTests.cs

@@ -12,6 +12,24 @@ namespace NuGet.Test
 {
     public class PackageReaderTests
     {
+        [Fact]
+        public void PackageReader_NestedReferenceItems()
+        {
+            var zip = TestPackages.GetZip(TestPackages.GetLibSubFolderPackage());
+
+            using (PackageReader reader = new PackageReader(zip))
+            {
+                var groups = reader.GetReferenceItems().ToArray();
+
+                Assert.Equal(1, groups.Count());
+
+                Assert.Equal(NuGetFramework.Parse("net40"), groups[0].TargetFramework);
+                Assert.Equal(2, groups[0].Items.Count());
+                Assert.Equal("lib/net40/test40.dll", groups[0].Items.ToArray()[0]);
+                Assert.Equal("lib/net40/x86/testx86.dll", groups[0].Items.ToArray()[1]);
+            }
+        }
+
         [Fact]
         public void PackageReader_MinClientVersion()
         {