GH-49634: [Ruby][Integration] Follow dictionary array API change

[kou]

Rationale for this change

GH-49621 changed dictionary array related API but we didn't follow the API change in integration test code.

What changes are included in this PR?

Follow dictionary array related API change in integration test code.

Are these changes tested?

Yes.

Are there any user-facing changes?

No.

• GitHub Issue: [Ruby][Integration] Integration tests fail due to undefined method 'array' for an instance of ArrowFormat::UTF8Array #49634

[github-actions]

⚠️ GitHub issue #49634 has been automatically assigned in GitHub to PR creator.

[Copilot]

Pull request overview

Updates the Ruby Arrow integration JSON reader to follow the dictionary-array API change introduced in GH-49621, so dictionary-encoded columns are constructed with the expected dictionary wrapper type.

Changes:

• Wrap the dictionary value array returned from read_dictionary in an ArrowFormat::Dictionary object.
• Pass the wrapped dictionary object into DictionaryType#build_array as the dictionaries collection.

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[Copilot]

read_dictionary can return nil when the dictionary id isn't present in the JSON. Wrapping that in Dictionary.new(type.id, dictionary_array) will defer the failure to a later NoMethodError (e.g., when DictionaryArray#to_a calls dictionary.array). Consider raising a clear exception here if dictionary_array is nil (include the dictionary id and value type) to fail fast with an actionable error.

Suggested change

	dictionary_array = read_dictionary(type.id, type.value_type)
	dictionary_array = read_dictionary(type.id, type.value_type)
	if dictionary_array.nil?
	raise "Dictionary with id #{type.id} and value type " \
	"#{type.value_type.inspect} is missing from JSON dictionaries"
	end

[kou]

+1

Integration test passes again.

[conbench-apache-arrow]

After merging your PR, Conbench analyzed the 2 benchmarking runs that have been run so far on merge-commit 3c25e69.

There were no benchmark performance regressions. 🎉

The full Conbench report has more details. It also includes information about 1 possible false positive for unstable benchmarks that are known to sometimes produce them.

[conbench-apache-arrow]

After merging your PR, Conbench analyzed the 2 benchmarking runs that have been run so far on merge-commit 3c25e69.

There were no benchmark performance regressions. 🎉

The full Conbench report has more details. It also includes information about 1 possible false positive for unstable benchmarks that are known to sometimes produce them.