[R] Expose ignore_extra_columns and pad_short_rows CSV parse options

[thisisnic]

Describe the enhancement requested

Arrow C++ 26.0.0 adds two new arrow::csv::ParseOptions fields:

• ignore_extra_columns (GH-50967: [C++] Allow CSV reader to ignore extra columns in rows with more columns #51118): rows with more columns than expected have the extra columns dropped instead of erroring.
• pad_short_rows (GH-50925: [C++] Allow CSV reader to pad rows with missing trailing fields #50926): rows with fewer columns than expected are padded with nulls instead of erroring.

Neither can be set from R. csv_parse_options() and CsvParseOptions$create() should accept both, and csv.cpp should pass them through:

arrow/r/R/csv.R

Lines 735 to 753 in 9479e68

	quote_char = '"',
	double_quote = TRUE,
	escaping = FALSE,
	escape_char = "\\",
	newlines_in_values = FALSE,
	ignore_empty_lines = TRUE
	) {
	csv___ParseOptions__initialize(
	list(
	delimiter = delimiter,
	quoting = quoting,
	quote_char = quote_char,
	double_quote = double_quote,
	escaping = escaping,
	escape_char = escape_char,
	newlines_in_values = newlines_in_values,
	ignore_empty_lines = ignore_empty_lines
	)
	)

arrow/r/src/csv.cpp

Lines 64 to 72 in 9479e68

	res->delimiter = cpp11::as_cpp<char>(options["delimiter"]);
	res->quoting = cpp11::as_cpp<bool>(options["quoting"]);
	res->quote_char = cpp11::as_cpp<char>(options["quote_char"]);
	res->double_quote = cpp11::as_cpp<bool>(options["double_quote"]);
	res->escape_char = cpp11::as_cpp<char>(options["escape_char"]);
	res->newlines_in_values = cpp11::as_cpp<bool>(options["newlines_in_values"]);
	res->ignore_empty_lines = cpp11::as_cpp<bool>(options["ignore_empty_lines"]);
	return res;
	}

Component(s)

R