Allow column vector inputs (#2635)

Fixes #2609

Author: lionel-

NEWS.md

@@ -20,14 +20,13 @@
     (#2610).
 
 *   Error: Column `y` must be a 1d atomic vector or a list
-  
-    Internally, ggplot2 now uses `as.data.frame(tibble::as_tibble(x))` to 
-    convert a list into a data frame. This improves ggplot2's support for 
+
+    Internally, ggplot2 now uses `as.data.frame(tibble::as_tibble(x))` to
+    convert a list into a data frame. This improves ggplot2's support for
     list-columns (needed for sf support), at a small cost: you can no longer
-    use matrix-columns. These are rarely used but are produced by `scale()`;
-    to continue to use `scale()` you'll need to wrap it with `as.numeric()`, 
-    e.g. `as.numeric(scale(x))`.
-  
+    use matrix-columns. Note that unlike tibble we still allow column vectors
+    such as returned by `base::scale()` because of their widespread use.
+
 *   Error: More than one expression parsed
 
     Previously `aes_string(x = c("a", "b", "c"))` silently returned 

R/geom-.r

@@ -116,7 +116,7 @@ Geom <- ggproto("Geom",
     missing_eval <- compact(missing_eval)
 
     if (empty(data)) {
-      data <- as.data.frame(tibble::as_tibble(missing_eval))
+      data <- as_gg_data_frame(missing_eval)
     } else {
       data[names(missing_eval)] <- missing_eval
     }

R/layer.r

@@ -235,7 +235,7 @@ Layer <- ggproto("Layer", NULL,
       evaled$PANEL <- data$PANEL
     }
     evaled <- lapply(evaled, unname)
-    evaled <- as.data.frame(tibble::as_tibble(evaled))
+    evaled <- as_gg_data_frame(evaled)
     evaled <- add_group(evaled)
     evaled
   },

R/utilities.r

@@ -414,3 +414,19 @@ seq_asc <- function(to, from) {
 # Needed to trigger package loading
 #' @importFrom tibble tibble
 NULL
+
+# Check inputs with tibble but allow column vectors (see #2609 and #2374)
+as_gg_data_frame <- function(x) {
+  x <- lapply(x, validate_column_vec)
+  as.data.frame(tibble::as_tibble(x))
+}
+validate_column_vec <- function(x) {
+  if (is_column_vec(x)) {
+    dim(x) <- NULL
+  }
+  x
+}
+is_column_vec <- function(x) {
+  dims <- dim(x)
+  length(dims) == 2L && dims[[2]] == 1L
+}

tests/testthat/test-layer.r

@@ -20,6 +20,13 @@ test_that("unknown NULL asthetic doesn't create warning (#1909)", {
   expect_warning(geom_point(aes(blah = NULL)), NA)
 })
 
+test_that("column vectors are allowed (#2609)", {
+  df <- data.frame(x = 1:10)
+  df$y <- scale(1:10) # Returns a column vector
+  p <- ggplot(df, aes(x, y))
+  expect_is(layer_data(p), "data.frame")
+})
+
 # Data extraction ---------------------------------------------------------
 
 test_that("layer_data returns a data.frame", {