fix(r): correct two int64 corruption bugs affecting list<int64> conversion

r/R/as-array.R

@@ -257,7 +257,7 @@ as_nanoarrow_array.list <- function(x, ..., schema = NULL) {
 
   array <- nanoarrow_array_init(schema)
 
-  child <- unlist(x, recursive = FALSE, use.names = FALSE)
+  child <- do.call(c, x)
   if (is.null(child)) {
     child_array <- as_nanoarrow_array.vctrs_unspecified(logical(), schema = na_na())
   } else {

r/src/materialize_int64.h

@@ -49,7 +49,7 @@ static inline int nanoarrow_materialize_int64(struct ArrayViewSlice* src,
       break;
     case NANOARROW_TYPE_INT64:
       memcpy(result + dst->offset,
-             src->array_view->buffer_views[1].data.as_int32 + raw_src_offset,
+             src->array_view->buffer_views[1].data.as_int64 + raw_src_offset,
              dst->length * sizeof(int64_t));
 
       // Set any nulls to NA_INTEGER64

r/tests/testthat/test-as-array.R

@@ -824,6 +824,29 @@ test_that("as_nanoarrow_array() works for list(integer()) -> na_list(na_int32())
   expect_identical(array$children[[1]]$length, 10L)
 })
 
+test_that("as_nanoarrow_array() works for list(integer64()) -> na_list(na_int64())", {
+  # GH932: unlist() silently strips the integer64 class from list elements,
+  # reinterpreting the underlying int64 bit pattern as a double and corrupting
+  # values before the child array is even built.
+  skip_if_not_installed("bit64")
+
+  big <- bit64::as.integer64(c("9223372036854775295", "2"))
+  x <- list(big, bit64::as.integer64("3"))
+  array <- as_nanoarrow_array(x, schema = na_list(na_int64()))
+
+  expect_identical(infer_nanoarrow_schema(array)$format, "+l")
+  expect_identical(array$length, 2L)
+  expect_identical(array$null_count, 0L)
+  expect_identical(infer_nanoarrow_schema(array$children[[1]])$format, "l")
+  expect_identical(array$children[[1]]$length, 3L)
+
+  to <- vctrs::new_list_of(list(), ptype = bit64::integer64())
+  expect_identical(
+    convert_array(array, to),
+    vctrs::new_list_of(list(big, bit64::as.integer64("3")), ptype = bit64::integer64())
+  )
+})
+
 test_that("as_nanoarrow_array() works for unspecified() -> na_na()", {
   skip_if_not_installed("vctrs")
 

r/tests/testthat/test-convert-array.R

@@ -744,6 +744,24 @@ test_that("convert to vector works for valid integer64()", {
   )
 })
 
+test_that("convert to vector works for int64 with a nonzero offset", {
+  # GH932: the int64 materializer read from buffer_views[1].data.as_int32
+  # (i.e., with int32-sized pointer arithmetic) instead of as_int64, so any
+  # slice with a nonzero starting offset (e.g., a list child sliced per-row)
+  # read from the wrong memory location.
+  skip_if_not_installed("bit64")
+
+  vals <- bit64::as.integer64(c("9223372036854775295", "2", "3"))
+  array <- as_nanoarrow_array(vals, schema = na_int64())
+
+  sliced <- nanoarrow_array_modify(array, list(offset = 1L, length = 2L))
+
+  expect_identical(
+    convert_array(sliced, bit64::integer64()),
+    vals[2:3]
+  )
+})
+
 test_that("convert to vector works for null -> integer64()", {
   skip_if_not_installed("bit64")