[ruby/csv] Resolve CSV::Converters and HeaderConverters lazy

It's for Ractor. If you want to use the built-in converters, you
should call Ractor.make_shareable(CSV::Converters) and/or
Ractor.make_shareable(CSV::HeaderConverters).

https://github.com/ruby/csv/commit/b0b1325d6b

1 files changed, 6 insertions, 2 deletions

diff --git a/lib/csv/fields_converter.rb b/lib/csv/fields_converter.rb
index 178ffb37bc..b206118d99 100644
--- a/lib/csv/fields_converter.rb
+++ b/lib/csv/fields_converter.rb
@@ -16,7 +16,7 @@ class CSV
       @empty_value = options[:empty_value]
       @empty_value_is_empty_string = (@empty_value == "")
       @accept_nil = options[:accept_nil]
-      @builtin_converters = options[:builtin_converters]
+      @builtin_converters_name = options[:builtin_converters_name]
       @need_static_convert = need_static_convert?
     end
 
@@ -24,7 +24,7 @@ class CSV
       if name.nil?  # custom converter
         @converters << converter
       else          # named converter
-        combo = @builtin_converters[name]
+        combo = builtin_converters[name]
         case combo
         when Array  # combo converter
           combo.each do |sub_name|
@@ -80,5 +80,9 @@ class CSV
       @need_static_convert or
         (not @converters.empty?)
     end
+
+    def builtin_converters
+      @builtin_converters ||= ::CSV.const_get(@builtin_converters_name)
+    end
   end
 end