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new 4053d6efa5 GH-51262: [Ruby] Add ListArray values constructor (#51263)
4053d6efa5 is described below
commit 4053d6efa5de72f7a997ac5fa59e064d41c09ff5
Author: Yifan Chen <[email protected]>
AuthorDate: Thu Sep 10 18:11:36 2026 -0700
GH-51262: [Ruby] Add ListArray values constructor (#51263)
### Rationale for this change
GH-50382 identified list arrays as a prerequisite for a consistent public
typed-array builder API. This adds the separately requested list constructor.
### What changes are included in this PR?
* Add `ArrowFormat::ListArray.new(type, values)` while preserving the
existing buffer-based constructor.
* Build list validity, offsets, and the child array from nested Ruby values
using the declared child type.
* Cover empty lists, null lists, and null child values.
### Are these changes tested?
Yes. The `red-arrow-format` suite passes locally (694 tests, 705
assertions).
### Are there any user-facing changes?
Yes. Callers can construct an `ArrowFormat::ListArray` directly from a list
type and nested Ruby values.
### AI assistance
AI assistance drafted the implementation and tests. The final patch was
reviewed against the existing typed constructors and low-level list array
representation, and the focused and full package tests were run locally.
* GitHub Issue: #51262
Lead-authored-by: Yifan Chen <[email protected]>
Co-authored-by: Yifan Chen <[email protected]>
Signed-off-by: Sutou Kouhei <[email protected]>
---
ruby/red-arrow-format/lib/arrow-format/array.rb | 47 +++++++++++++++++++++
ruby/red-arrow-format/lib/arrow-format/type.rb | 4 ++
ruby/red-arrow-format/test/test-list-array.rb | 54 +++++++++++++++++++++++++
3 files changed, 105 insertions(+)
diff --git a/ruby/red-arrow-format/lib/arrow-format/array.rb
b/ruby/red-arrow-format/lib/arrow-format/array.rb
index 20929493e9..ebf8b1ec68 100644
--- a/ruby/red-arrow-format/lib/arrow-format/array.rb
+++ b/ruby/red-arrow-format/lib/arrow-format/array.rb
@@ -1037,6 +1037,53 @@ module ArrowFormat
end
class ListArray < VariableSizeListArray
+ include BufferAlignable
+
+ def initialize(type, *args)
+ if args.size == 1
+ args = build_data(type, args.first)
+ elsif args.size != 4
+ raise ArgumentError,
+ "wrong number of arguments (given #{args.size + 1}, expected 2
or 5)"
+ end
+
+ super(type, *args)
+ end
+
+ private
+ def build_data(type, data)
+ n = 0
+ validity_buffer_builder = nil
+
+ child_values = []
+ offsets = [0]
+ data.each_with_index do |value, i|
+ if value.nil?
+ validity_buffer_builder ||= SparseBitmapBuilder.new
+ validity_buffer_builder.unset(i)
+ else
+ child_values.concat(value)
+ end
+ offsets << child_values.size
+ n += 1
+ end
+
+ validity_buffer = validity_buffer_builder&.finish(n)
+
+ offsets_data = offsets.pack("#{type.offset_pack_template}*")
+ pad!(offsets_data, buffer_padding_size(offsets_data))
+ offsets_data.freeze
+ offsets_buffer = IO::Buffer.for(offsets_data)
+
+ child = type.child.type.build_array(child_values)
+
+ [
+ n,
+ validity_buffer,
+ offsets_buffer,
+ child,
+ ]
+ end
end
class LargeListArray < VariableSizeListArray
diff --git a/ruby/red-arrow-format/lib/arrow-format/type.rb
b/ruby/red-arrow-format/lib/arrow-format/type.rb
index 9a6d1f3ed0..432dfdf3f8 100644
--- a/ruby/red-arrow-format/lib/arrow-format/type.rb
+++ b/ruby/red-arrow-format/lib/arrow-format/type.rb
@@ -1021,6 +1021,10 @@ module ArrowFormat
:s32 # TODO: big endian support
end
+ def offset_pack_template
+ "l"
+ end
+
def build_array(...)
ListArray.new(self, ...)
end
diff --git a/ruby/red-arrow-format/test/test-list-array.rb
b/ruby/red-arrow-format/test/test-list-array.rb
new file mode 100644
index 0000000000..d3494a09c6
--- /dev/null
+++ b/ruby/red-arrow-format/test/test-list-array.rb
@@ -0,0 +1,54 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements. See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership. The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License. You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied. See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+class TestListArray < Test::Unit::TestCase
+ def setup
+ child = ArrowFormat::Field.new("item", ArrowFormat::Int32Type.singleton)
+ @type = ArrowFormat::ListType.new(child)
+ end
+
+ sub_test_case("#initialize") do
+ def test_no_null
+ values = [[-1, 0], [], [1, 2, 3]]
+ array = ArrowFormat::ListArray.new(@type, values)
+ assert_same(@type, array.type)
+ assert_equal(values, array.to_a)
+ end
+
+ def test_null_list
+ values = [[1, 2], nil, [], [3]]
+ array = ArrowFormat::ListArray.new(@type, values)
+ assert_equal([0, 2, 2, 2, 3], array.offsets)
+ assert_equal([1, 2, 3], array.child.to_a)
+ assert_equal(values, array.to_a)
+ end
+
+ def test_null_child
+ values = [[1, nil], [], [nil, 2]]
+ array = ArrowFormat::ListArray.new(@type, values)
+ assert_equal([1, nil, nil, 2], array.child.to_a)
+ assert_equal(values, array.to_a)
+ end
+
+ def test_empty
+ array = ArrowFormat::ListArray.new(@type, [])
+ assert_equal([0], array.offsets)
+ assert_equal([], array.child.to_a)
+ assert_equal([], array.to_a)
+ end
+ end
+end
