Honor concurrent_downloads from gemrc

Author: afurm

lib/rubygems/config_file.rb

@@ -220,7 +220,8 @@ def initialize(args)
     @hash.transform_keys! do |k|
       # gemhome and gempath are not working with symbol keys
       if %w[backtrace bulk_threshold verbose update_sources cert_expiration_length_days
-            install_extension_in_lib ipv4_fallback_enabled global_gem_cache sources
+            concurrent_downloads install_extension_in_lib ipv4_fallback_enabled
+            global_gem_cache sources
             disable_default_gem_server ssl_verify_mode ssl_ca_cert ssl_client_cert].include?(k)
         k.to_sym
       else
@@ -233,7 +234,7 @@ def initialize(args)
     @bulk_threshold              = @hash[:bulk_threshold]              if @hash.key? :bulk_threshold
     @verbose                     = @hash[:verbose]                     if @hash.key? :verbose
     @update_sources              = @hash[:update_sources]              if @hash.key? :update_sources
-    # TODO: We should handle concurrent_downloads same as other options
+    @concurrent_downloads        = @hash[:concurrent_downloads]        if @hash.key? :concurrent_downloads
     @cert_expiration_length_days = @hash[:cert_expiration_length_days] if @hash.key? :cert_expiration_length_days
     @install_extension_in_lib    = @hash[:install_extension_in_lib]    if @hash.key? :install_extension_in_lib
     @ipv4_fallback_enabled       = @hash[:ipv4_fallback_enabled]       if @hash.key? :ipv4_fallback_enabled

test/rubygems/test_gem_config_file.rb

@@ -113,6 +113,16 @@ def test_initialize_global_gem_cache_gemrc
     assert_equal true, @cfg.global_gem_cache
   end
 
+  def test_initialize_concurrent_downloads
+    File.open @temp_conf, "w" do |fp|
+      fp.puts "concurrent_downloads: 2"
+    end
+
+    util_config_file %W[--config-file #{@temp_conf}]
+
+    assert_equal 2, @cfg.concurrent_downloads
+  end
+
   def test_initialize_handle_arguments_config_file
     util_config_file %W[--config-file #{@temp_conf}]