ARROW-13087: [R] Expose Parquet ArrowReaderProperties::coerce_int96_timestamp_unit_

r/R/parquet.R

@@ -577,6 +577,12 @@ ParquetArrowReaderProperties <- R6Class("ParquetArrowReaderProperties",
     },
     set_read_dictionary = function(column_index, read_dict) {
       parquet___arrow___ArrowReaderProperties__set_read_dictionary(self, column_index, read_dict)
+    },
+    coerce_int96_timestamp_unit = function() {
+      parquet___arrow___ArrowReaderProperties__get_coerce_int96_timestamp_unit(self)
+    },
+    set_coerce_int96_timestamp_unit = function(unit) {
+      parquet___arrow___ArrowReaderProperties__set_coerce_int96_timestamp_unit(self, unit)
     }
   ),
   active = list(

r/src/parquet.cpp

@@ -69,6 +69,20 @@ void parquet___arrow___ArrowReaderProperties__set_read_dictionary(
   properties->set_read_dictionary(column_index, read_dict);
 }
 
+// [[parquet::export]]
+void parquet___arrow___ArrowReaderProperties__set_coerce_int96_timestamp_unit(
+    const std::shared_ptr<parquet::ArrowReaderProperties>& properties,
+    arrow::TimeUnit::type unit) {
+  properties->set_coerce_int96_timestamp_unit(unit);
+}
+
+// [[parquet::export]]
+arrow::TimeUnit::type
+parquet___arrow___ArrowReaderProperties__get_coerce_int96_timestamp_unit(
+    const std::shared_ptr<parquet::ArrowReaderProperties>& properties) {
+  return properties->coerce_int96_timestamp_unit();
+}
+
 // [[parquet::export]]
 std::shared_ptr<parquet::arrow::FileReader> parquet___arrow___FileReader__OpenFile(
     const std::shared_ptr<arrow::io::RandomAccessFile>& file,

r/tests/testthat/test-parquet.R

@@ -324,3 +324,31 @@ test_that("ParquetFileWrite chunk_size calculation doesn't have integer overflow
   # but our max_chunks is respected
   expect_equal(calculate_chunk_size(101, 1, 25, 2), 51)
 })
+
+test_that("deprecated int96 timestamp unit can be specified when reading Parquet files", {
+  tf <- tempfile()
+  on.exit(unlink(tf))
+
+  table <- Table$create(
+    some_datetime = as.POSIXct("2001-01-01 12:34:56.789")
+  )
+
+  write_parquet(
+    table,
+    tf,
+    use_deprecated_int96_timestamps = TRUE
+  )
+
+  props <- ParquetArrowReaderProperties$create()
+  props$set_coerce_int96_timestamp_unit(TimeUnit$MILLI)
+  expect_identical(props$coerce_int96_timestamp_unit(), TimeUnit$MILLI)
+
+  result <- read_parquet(
+    tf,
+    as_data_frame = FALSE,
+    props = props
+  )
+
+  expect_identical(result$some_datetime$type$unit(), TimeUnit$MILLI)
+  expect_true(result$some_datetime == table$some_datetime)
+})