From fe832e480424f034d88777eced5e0cc8aa4d5d8a Mon Sep 17 00:00:00 2001
From: Lionel Henry <lionel.hry@gmail.com>
Date: Wed, 5 Aug 2020 10:46:38 +0200
Subject: [PATCH 1/2] Recycle names in `map2()`

Closes #779
---
 src/map.c                  | 14 ++++++++++----
 tests/testthat/test-map2.R |  7 +++++++
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/src/map.c b/src/map.c
index e14b2af0..f8bda74c 100644
--- a/src/map.c
+++ b/src/map.c
@@ -7,14 +7,20 @@
 #include "utils.h"
 
 void copy_names(SEXP from, SEXP to) {
-  if (Rf_length(from) != Rf_length(to))
-    return;
-
   SEXP names = Rf_getAttrib(from, R_NamesSymbol);
-  if (Rf_isNull(names))
+  if (names == R_NilValue) {
     return;
+  }
+
+  R_len_t n = Rf_length(to);
+
+  if (Rf_length(names) != n) {
+    names = short_vec_recycle(names, n);
+  }
+  PROTECT(names);
 
   Rf_setAttrib(to, R_NamesSymbol, names);
+  UNPROTECT(1);
 }
 
 void check_vector(SEXP x, const char *name) {
diff --git a/tests/testthat/test-map2.R b/tests/testthat/test-map2.R
index c307bd59..48a00bff 100644
--- a/tests/testthat/test-map2.R
+++ b/tests/testthat/test-map2.R
@@ -59,3 +59,10 @@ test_that("map2() with empty input copies names", {
   expect_identical(map2_chr(named_list, list(), identity), named(chr()))
   expect_identical(map2_raw(named_list, list(), identity), named(raw()))
 })
+
+test_that("map2() recycle names (#779)", {
+  expect_identical(
+    map2(c(a = 1), 1:2, ~ .x),
+    list(a = 1, a = 1)
+  )
+})

From 332cc5d10df945335cc2a482564240c84a6e1b99 Mon Sep 17 00:00:00 2001
From: Lionel Henry <lionel.hry@gmail.com>
Date: Wed, 5 Aug 2020 16:53:14 +0200
Subject: [PATCH 2/2] Add test for `pmap()`

And NEWS bullet
---
 NEWS.md                    | 3 +++
 tests/testthat/test-map2.R | 6 +++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/NEWS.md b/NEWS.md
index ced4331b..2a5bfc79 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -11,6 +11,9 @@
 
 ## Features and fixes
 
+* `map2()` and `pmap()` now recycle names of their first input if
+  needed (#783).
+
 * `every()` and `some()` now properly check the return value of their
   predicate function. It must now return a `TRUE`, `FALSE`, or `NA`.
 
diff --git a/tests/testthat/test-map2.R b/tests/testthat/test-map2.R
index 48a00bff..7941468a 100644
--- a/tests/testthat/test-map2.R
+++ b/tests/testthat/test-map2.R
@@ -60,9 +60,13 @@ test_that("map2() with empty input copies names", {
   expect_identical(map2_raw(named_list, list(), identity), named(raw()))
 })
 
-test_that("map2() recycle names (#779)", {
+test_that("map2() and pmap() recycle names (#779)", {
   expect_identical(
     map2(c(a = 1), 1:2, ~ .x),
     list(a = 1, a = 1)
   )
+  expect_identical(
+    pmap(list(c(a = 1), 1:2), ~ .x),
+    list(a = 1, a = 1)
+  )
 })