Allow reading list of connections (#514)

* Allow reading list of connections

* Use sapply dots

* Standardise single connection

* Add NEWS bullet

---------

Co-authored-by: Jenny Bryan <jenny.f.bryan@gmail.com>

NEWS.md

@@ -1,5 +1,7 @@
 # vroom (development version)
 
+* It is now possible (again?) to read from a list of connections (@bairdj, #514).
+
 * Internal change for compatibility with cpp11 >= 0.4.6 (@DavisVaughan).
 
 # vroom 1.6.3

R/path.R

@@ -27,14 +27,11 @@ standardise_path <- function(path, user_env = caller_env(2)) {
   }
 
   if (inherits(path, "connection")) {
-    # If the connection is `stdin()`, change it to `file("stdin")`, as we don't
-    # support text mode connections.
-
-    if (path == stdin()) {
-      return(list(file("stdin")))
-    }
+    return(list(standardise_connection(path)))
+  }
 
-    return(list(path))
+  if (is_list(path) && all(sapply(path, inherits, "connection"))) {
+    return(lapply(path, standardise_connection))
   }
 
   if (is.character(path)) {
@@ -66,6 +63,17 @@ standardise_path <- function(path, user_env = caller_env(2)) {
   as.list(enc2utf8(path))
 }
 
+standardise_connection <- function(con) {
+  # If the connection is `stdin()`, change it to `file("stdin")`, as we don't
+  # support text mode connections.
+
+  if (con == stdin()) {
+    return(file("stdin"))
+  }
+
+  con
+}
+
 standardise_one_path <- function (path, write = FALSE) {
 
   if (is.raw(path)) {

tests/testthat/test-multi-file.R

@@ -75,7 +75,7 @@ test_that("vroom works with many connections", {
   dir.create(dir)
   on.exit(unlink(dir, recursive = TRUE))
 
-  for (i in seq_len(200)) {
+  for (i in seq_len(20)) {
     vroom_write(
       tibble::tibble(
         x = rnorm(10),
@@ -87,11 +87,12 @@ test_that("vroom works with many connections", {
   }
 
   files <- list.files(dir, pattern = ".*[.]csv[.]gz", full.names = TRUE)
+  connections <- lapply(files, gzfile)
 
-  res <- vroom::vroom(files, col_types = list())
+  res <- vroom::vroom(connections, col_types = list())
 
   expect_equal(colnames(res), c("x", "y"))
-  expect_equal(NROW(res), 2000)
+  expect_equal(NROW(res), 200)
 })
 
 test_that("vroom errors if numbers of columns are inconsistent", {