Reapply "[rubygems/rubygems] Fix require of a default gem when unresolved gems depend on it"

This reverts commit 54552b89e73fc616ba47c1c87d33625af99cbce9.

lib/rubygems/core_ext/kernel_require.rb

@@ -62,6 +62,8 @@ module Kernel
 
         Kernel.send(:gem, spec.name, Gem::Requirement.default_prerelease) unless
           resolved_path
+
+        next
       end
 
       # If there are no unresolved deps, then we can use just try

test/rubygems/test_require.rb

@@ -540,6 +540,26 @@ class TestGemRequire < Gem::TestCase
     assert_equal %w[default-3.0.0.rc2], loaded_spec_names
   end
 
+  def test_default_gem_with_unresolved_gems_depending_on_it
+    net_http_old = util_spec "net-http", "0.1.1", nil, "lib/net/http.rb"
+    install_gem net_http_old
+
+    net_http_default = new_default_spec "net-http", "0.3.0", nil, "net/http.rb"
+    install_default_gems net_http_default
+
+    faraday_1 = util_spec "faraday", "1", { "net-http" => ">= 0" }
+    install_gem faraday_1
+
+    faraday_2 = util_spec "faraday", "2", { "net-http" => ">= 0" }
+    install_gem faraday_2
+
+    chef = util_spec "chef", "1", { "faraday" => [">= 1", "< 3"] }, "lib/chef.rb"
+    install_gem chef
+
+    assert_require "chef"
+    assert_require "net/http"
+  end
+
   def loaded_spec_names
     Gem.loaded_specs.values.map(&:full_name).sort
   end