GH-44742: [Ruby] Fix a bug that empty struct list value can't be built (

#44763) ### Rationale for this change This codes add a list value but no struct value isn't added: ```ruby require "arrow" schema = Arrow::Schema.new( [ Arrow::Field.new("structs", Arrow::ListDataType.new( Arrow::StructDataType.new([ Arrow::Field.new("foo", :int64), Arrow::Field.new("bar", :int64) ]) )) ] ) Arrow::RecordBatchBuilder.build(schema, [{structs: []}]) ``` ### What changes are included in this PR? Don't add a list value. ### Are these changes tested? Yes. ### Are there any user-facing changes? Yes. * GitHub Issue: #44742 Authored-by: Sutou Kouhei <[email protected]> Signed-off-by: Sutou Kouhei <[email protected]>
apache · Nov 19, 2024 · 66c2cf0 · 66c2cf0
1 parent bc36282
commit 66c2cf0
Show file tree

Hide file tree

Showing 2 changed files with 10 additions and 0 deletions.
diff --git a/ruby/red-arrow/lib/arrow/list-array-builder.rb b/ruby/red-arrow/lib/arrow/list-array-builder.rb
@@ -54,6 +54,7 @@ def append_value(*args)
         when nil
           append_null
         when ::Array
+          return if value.empty?
           append_value_raw
           @value_builder ||= value_builder
           @value_builder.append(*value)

diff --git a/ruby/red-arrow/test/test-list-array-builder.rb b/ruby/red-arrow/test/test-list-array-builder.rb
@@ -33,6 +33,15 @@ def setup
       array = @builder.finish
       assert_equal([true, false, true], array[0].to_a)
     end
+
+    test("Struct[]") do
+      item_type = Arrow::StructDataType.new([{name: "visible", type: :boolean}])
+      data_type = Arrow::ListDataType.new(name: "struct", data_type: item_type)
+      builder = Arrow::ListArrayBuilder.new(data_type)
+      builder.append_value([])
+      array = builder.finish
+      assert_equal([], array[0].to_a)
+    end
   end
 
   sub_test_case("#append_values") do