News and comment

r/NEWS.md

@@ -21,6 +21,7 @@
 
 * R functions that users write that use functions that Arrow supports in dataset queries now can be used in queries too. Previously, only functions that used arithmetic operators worked. For example, `time_hours <- function(mins) mins / 60` worked, but `time_hours_rounded <- function(mins) round(mins / 60)` did not; now both work. These are automatic translations rather than true user-defined functions (UDFs); for UDFs, see `register_scalar_function()`. (#41223)
 * `summarize()` supports more complex expressions, and correctly handles cases where column names are reused in expressions. 
+* The `na_matches` argument to the `dplyr::*_join()` functions is now supported. This argument controls whether `NA` values are considered equal when joining. (#41358)
 
 # arrow 16.0.0
 

r/src/compute-exec.cpp

@@ -418,6 +418,9 @@ std::shared_ptr<acero::ExecNode> ExecNode_Join(
  for (auto&& name : left_keys) {
  left_refs.emplace_back(std::move(name));
  // Populate key_cmps in this loop, one for each key
+ // Note that Acero supports having different values for each key, but dplyr
+ // only supports one value for all keys, so we're only going to support that
+ // for now.
  key_cmps.emplace_back(na_matches ? acero::JoinKeyCmp::IS : acero::JoinKeyCmp::EQ);
  }
  for (auto&& name : right_keys) {