Patch by MSP-Greg
Aligns two ruby/ruby files with the same rubygems/rubygems files
diff --git a/lib/rubygems/resolver.rb b/lib/rubygems/resolver.rb
index 8f0db512a2..13ee035e4c 100644
--- a/lib/rubygems/resolver.rb
+++ b/lib/rubygems/resolver.rb
@@ -230,8 +230,28 @@ def search_for(dependency)
       exc.errors = @set.errors
       raise exc
     end
-    possibles.sort_by { |s| [s.source, s.version, Gem::Platform.local =~ s.platform ? 1 : 0] }.
-      map { |s| ActivationRequest.new s, dependency, [] }
+
+    sources = []
+
+    groups = Hash.new { |hash, key| hash[key] = [] }
+
+    # create groups & sources in the same loop
+    sources = possibles.map { |spec|
+      source = spec.source
+      groups[source] << spec
+      source
+    }.uniq.reverse
+
+    activation_requests = []
+
+    sources.each do |source|
+      groups[source].
+        sort_by { |spec| [spec.version, Gem::Platform.local =~ spec.platform ? 1 : 0] }.
+        map { |spec| ActivationRequest.new spec, dependency, [] }.
+        each { |activation_request| activation_requests << activation_request }
+    end
+
+    activation_requests
   end
 
   def dependencies_for(specification)
diff --git a/test/rubygems/test_gem_resolver.rb b/test/rubygems/test_gem_resolver.rb
index e95a37162d..417f0580f7 100644
--- a/test/rubygems/test_gem_resolver.rb
+++ b/test/rubygems/test_gem_resolver.rb
@@ -683,6 +683,32 @@ def test_second_level_backout
     assert_resolves_to [b1, c1, d2], r
   end
 
+  def test_sorts_by_source_then_version
+    sourceA = Gem::Source.new 'http://example.com/a'
+    sourceB = Gem::Source.new 'http://example.com/b'
+    sourceC = Gem::Source.new 'http://example.com/c'
+
+    spec_A_1 = new_spec 'some-dep', '0.0.1'
+    spec_A_2 = new_spec 'some-dep', '1.0.0'
+    spec_B_1 = new_spec 'some-dep', '0.0.1'
+    spec_B_2 = new_spec 'some-dep', '0.0.2'
+    spec_C_1 = new_spec 'some-dep', '0.1.0'
+
+    set = StaticSet.new [
+      Gem::Resolver::SpecSpecification.new(nil, spec_B_1, sourceB),
+      Gem::Resolver::SpecSpecification.new(nil, spec_B_2, sourceB),
+      Gem::Resolver::SpecSpecification.new(nil, spec_C_1, sourceC),
+      Gem::Resolver::SpecSpecification.new(nil, spec_A_2, sourceA),
+      Gem::Resolver::SpecSpecification.new(nil, spec_A_1, sourceA),
+    ]
+
+    dependency = make_dep 'some-dep', '> 0'
+
+    resolver = Gem::Resolver.new [dependency], set
+
+    assert_resolves_to [spec_B_2], resolver
+  end
+
   def test_select_local_platforms
     r = Gem::Resolver.new nil, nil