From 34c01ccd3b22fadd9c662a5ef4b386469a3dec59 Mon Sep 17 00:00:00 2001
From: Kamil Slowikowski <kslowikowski@gmail.com>
Date: Tue, 28 Aug 2018 12:14:43 -0400
Subject: [PATCH 01/18] use parse_safe() in geom_text()

The built in `parse()` function silently drops items:

    length(parse(text = c("alpha", "", "gamma")))

We expect the length to be 3, but instead it is 2.

So, we add a new function `parse_safe()` that keeps all items.

This addresses issue #2864
---
 R/geom-label.R |  2 +-
 R/geom-text.r  |  3 +--
 R/utilities.r  | 11 +++++++++++
 3 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/R/geom-label.R b/R/geom-label.R
index 921f4784ac..3a1d3250b5 100644
--- a/R/geom-label.R
+++ b/R/geom-label.R
@@ -63,7 +63,7 @@ GeomLabel <- ggproto("GeomLabel", Geom,
                         label.size = 0.25) {
     lab <- data$label
     if (parse) {
-      lab <- parse(text = as.character(lab))
+      lab <- parse_safe(text = as.character(lab))
     }
 
     data <- coord$transform(data, panel_params)
diff --git a/R/geom-text.r b/R/geom-text.r
index d86fee04a6..88be5c721d 100644
--- a/R/geom-text.r
+++ b/R/geom-text.r
@@ -159,7 +159,6 @@ geom_text <- function(mapping = NULL, data = NULL,
   )
 }
 
-
 #' @rdname ggplot2-ggproto
 #' @format NULL
 #' @usage NULL
@@ -176,7 +175,7 @@ GeomText <- ggproto("GeomText", Geom,
                         na.rm = FALSE, check_overlap = FALSE) {
     lab <- data$label
     if (parse) {
-      lab <- parse(text = as.character(lab))
+      lab <- parse_safe(text = as.character(lab))
     }
 
     data <- coord$transform(data, panel_params)
diff --git a/R/utilities.r b/R/utilities.r
index 06651d7251..4dc2950e5a 100644
--- a/R/utilities.r
+++ b/R/utilities.r
@@ -430,3 +430,14 @@ is_column_vec <- function(x) {
   dims <- dim(x)
   length(dims) == 2L && dims[[2]] == 1L
 }
+
+# Parse a vector of expressions without silently dropping any items.
+# (see #2864)
+parse_safe <- function(text) {
+  text <- as.character(text)
+  ix <- which(sapply(text, function(x) {
+    length(parse(text = x)) == 0
+  }))
+  text[ix] <- NA
+  parse(text = text)
+}

From fe7216ad3df09f9074d3301b75078138084881e1 Mon Sep 17 00:00:00 2001
From: Kamil Slowikowski <kslowikowski@gmail.com>
Date: Thu, 30 Aug 2018 08:38:21 -0400
Subject: [PATCH 02/18] update parse_safe()

Use Hadley's code to parse the expressions once instead of twice.

Use `parse(..., keep.source = FALSE)`, as Claus recommended.

Add an example to demonstrate why `parse_safe()` is needed.
---
 R/utilities.r | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/R/utilities.r b/R/utilities.r
index 4dc2950e5a..5e5ab6f9c0 100644
--- a/R/utilities.r
+++ b/R/utilities.r
@@ -431,13 +431,20 @@ is_column_vec <- function(x) {
   length(dims) == 2L && dims[[2]] == 1L
 }
 
-# Parse a vector of expressions without silently dropping any items.
-# (see #2864)
+#' Parse a vector of expressions without silently dropping any items.
+#'
+#' For more discussion, see #2864
+#' @keywords internal
+#' @examples
+#' length(parse(text = c("alpha", "", "gamma")))
+#' #> 2
+#' length(parse_safe(text = c("alpha", "", "gamma")))
+#' #> 3
 parse_safe <- function(text) {
-  text <- as.character(text)
-  ix <- which(sapply(text, function(x) {
-    length(parse(text = x)) == 0
-  }))
-  text[ix] <- NA
-  parse(text = text)
+  out <- vector("expression", length(text))
+  for (i in seq_along(text)) {
+    expr <- parse(text = text[[i]])
+    out[[i]] <- if (length(expr) == 0) NA else expr[[1]]
+  }
+  out
 }

From aa9bfc365aa604eea4c25d3c37f21a2e82891831 Mon Sep 17 00:00:00 2001
From: Kamil Slowikowski <kslowikowski@gmail.com>
Date: Thu, 30 Aug 2018 08:40:11 -0400
Subject: [PATCH 03/18] add tests for parse_safe()

---
 tests/testthat/test-parse.r | 52 +++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)
 create mode 100644 tests/testthat/test-parse.r

diff --git a/tests/testthat/test-parse.r b/tests/testthat/test-parse.r
new file mode 100644
index 0000000000..67670e91df
--- /dev/null
+++ b/tests/testthat/test-parse.r
@@ -0,0 +1,52 @@
+context("Parsing expressions")
+
+expect_equal(
+  parse_safe(c("", " ", " \n  \n ")),
+  expression(NA, NA, NA)
+)
+
+expect_equal(
+  parse_safe(c("A", "B", "C")),
+  expression(A, B, C)
+)
+
+expect_equal(
+  parse_safe(c("alpha", "beta", "gamma")),
+  expression(alpha, beta, gamma)
+)
+
+expect_equal(
+  parse_safe(c("alpha", "", "gamma", " ")),
+  expression(alpha, NA, gamma, NA)
+)
+
+expect_equal(
+  parse_safe(c("alpha ~ beta", " ", "integral(f(x) * dx, a, b)")),
+  expression(alpha ~ beta, NA, integral(f(x) * dx, a, b))
+)
+
+expect_equal(
+  parse_safe(c("alpha \n beta", " ", "integral(f(x) * dx, a, b)")),
+  expression(alpha, NA, integral(f(x) * dx, a, b))
+)
+
+expect_equal(
+  parse_safe(c(NA, "a", NA, "alpha")),
+  expression(NA, a, NA, alpha)
+)
+
+expect_equal(
+  parse_safe(factor(c("alpha", "beta", ""))),
+  expression(2, 3, 1)
+)
+
+expect_equal(
+  parse_safe(factor(c(NA, "a", NA, "alpha"))),
+  expression(NA, 1, NA, 2)
+)
+
+expect_equal(
+  parse_safe(c(NA, 1, 2, "a \n b")),
+  expression(NA, 1, 2, a)
+)
+

From 5dd869e5992f0e61a0dc6c449e9905add5ad24dd Mon Sep 17 00:00:00 2001
From: Kamil Slowikowski <kslowikowski@gmail.com>
Date: Thu, 30 Aug 2018 08:55:36 -0400
Subject: [PATCH 04/18] add note about parse(text = NULL)

---
 R/utilities.r | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/R/utilities.r b/R/utilities.r
index 5e5ab6f9c0..d8d214768b 100644
--- a/R/utilities.r
+++ b/R/utilities.r
@@ -433,7 +433,10 @@ is_column_vec <- function(x) {
 
 #' Parse a vector of expressions without silently dropping any items.
 #'
+#' Note that `parse(text = NULL)` does not work and should be avoided.
+#'
 #' For more discussion, see #2864
+#'
 #' @keywords internal
 #' @examples
 #' length(parse(text = c("alpha", "", "gamma")))

From 252e7b2a4fcd7c72602bb7f5e71e5ef6731f52b2 Mon Sep 17 00:00:00 2001
From: Kamil Slowikowski <kslowikowski@gmail.com>
Date: Thu, 30 Aug 2018 13:40:30 -0400
Subject: [PATCH 05/18] use parse_safe() in sf.R

This patch fixes an example that triggers an error:

    library(ggplot2)
    nc <- sf::st_read(system.file("shape/nc.shp", package = "sf"), quiet = TRUE)
    ggplot(nc) +
      geom_sf(aes(fill = AREA)) +
      scale_y_continuous(
        breaks = c(34, 35, 36),
        labels = c("34*degree*N", "", "36*degree*N")
      )
    #> Error in parse(text = x)[[1]]: subscript out of bounds

See #2867 for more details.
---
 R/sf.R | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/R/sf.R b/R/sf.R
index 3d9ff0fae9..b2e76abf0b 100644
--- a/R/sf.R
+++ b/R/sf.R
@@ -476,10 +476,6 @@ CoordSf <- ggproto("CoordSf", CoordCartesian,
     if (!is.null(graticule$plot12))
       graticule$degree_label[!graticule$plot12] <- NA
 
-    # parse labels into expressions if required
-    if (any(grepl("degree", graticule$degree_label)))
-      graticule$degree_label <- lapply(graticule$degree_label, function(x) parse(text = x)[[1]])
-
     graticule
   },
 
@@ -553,11 +549,18 @@ CoordSf <- ggproto("CoordSf", CoordCartesian,
     graticule <- panel_params$graticule
     east <- graticule[graticule$type == "E" & !is.na(graticule$degree_label), ]
 
+    labs <- east$degree_label
+
+    # parse labels into expressions if required
+    if (any(grepl("degree", labs))) {
+      labs <- parse_safe(as.character(labs))
+    }
+
     list(
       top = nullGrob(),
       bottom = guide_axis(
         east$x_start,
-        east$degree_label,
+        labs,
         position = "bottom",
         theme = theme
       )
@@ -568,10 +571,17 @@ CoordSf <- ggproto("CoordSf", CoordCartesian,
     graticule <- panel_params$graticule
     north <- graticule[graticule$type == "N" & !is.na(graticule$degree_label), ]
 
+    labs <- north$degree_label
+
+    # parse labels into expressions if required
+    if (any(grepl("degree", labs))) {
+      labs <- parse_safe(as.character(labs))
+    }
+
     list(
       left = guide_axis(
         north$y_start,
-        north$degree_label,
+        labs,
         position = "left",
         theme = theme
       ),

From 4b6b02f4ea2b34b86003555e6e2587814cb236ce Mon Sep 17 00:00:00 2001
From: Kamil Slowikowski <kslowikowski@gmail.com>
Date: Sun, 2 Sep 2018 22:03:46 -0400
Subject: [PATCH 06/18] move parse_safe() tests to test-utilities.r

---
 tests/testthat/test-parse.r     | 52 ---------------------------------
 tests/testthat/test-utilities.r | 49 +++++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+), 52 deletions(-)
 delete mode 100644 tests/testthat/test-parse.r

diff --git a/tests/testthat/test-parse.r b/tests/testthat/test-parse.r
deleted file mode 100644
index 67670e91df..0000000000
--- a/tests/testthat/test-parse.r
+++ /dev/null
@@ -1,52 +0,0 @@
-context("Parsing expressions")
-
-expect_equal(
-  parse_safe(c("", " ", " \n  \n ")),
-  expression(NA, NA, NA)
-)
-
-expect_equal(
-  parse_safe(c("A", "B", "C")),
-  expression(A, B, C)
-)
-
-expect_equal(
-  parse_safe(c("alpha", "beta", "gamma")),
-  expression(alpha, beta, gamma)
-)
-
-expect_equal(
-  parse_safe(c("alpha", "", "gamma", " ")),
-  expression(alpha, NA, gamma, NA)
-)
-
-expect_equal(
-  parse_safe(c("alpha ~ beta", " ", "integral(f(x) * dx, a, b)")),
-  expression(alpha ~ beta, NA, integral(f(x) * dx, a, b))
-)
-
-expect_equal(
-  parse_safe(c("alpha \n beta", " ", "integral(f(x) * dx, a, b)")),
-  expression(alpha, NA, integral(f(x) * dx, a, b))
-)
-
-expect_equal(
-  parse_safe(c(NA, "a", NA, "alpha")),
-  expression(NA, a, NA, alpha)
-)
-
-expect_equal(
-  parse_safe(factor(c("alpha", "beta", ""))),
-  expression(2, 3, 1)
-)
-
-expect_equal(
-  parse_safe(factor(c(NA, "a", NA, "alpha"))),
-  expression(NA, 1, NA, 2)
-)
-
-expect_equal(
-  parse_safe(c(NA, 1, 2, "a \n b")),
-  expression(NA, 1, 2, a)
-)
-
diff --git a/tests/testthat/test-utilities.r b/tests/testthat/test-utilities.r
index aa42cf49f1..a98c6052b1 100644
--- a/tests/testthat/test-utilities.r
+++ b/tests/testthat/test-utilities.r
@@ -43,3 +43,52 @@ test_that("find_args behaves correctly", {
   # Defaults are overwritten
   expect_true(test_fun(arg2 = TRUE)$arg2)
 })
+
+test_that("parse_safe works with simple expressions", {
+  expect_equal(
+    parse_safe(c("", " ", "     ")),
+    expression(NA, NA, NA)
+  )
+
+  expect_equal(
+    parse_safe(c("A", "B", "C")),
+    expression(A, B, C)
+  )
+
+  expect_equal(
+    parse_safe(c("alpha", "", "gamma", " ")),
+    expression(alpha, NA, gamma, NA)
+  )
+
+  expect_equal(
+    parse_safe(c(NA, "a", NA, "alpha")),
+    expression(NA, a, NA, alpha)
+  )
+
+  expect_equal(
+    parse_safe(factor(c("alpha", "beta", ""))),
+    expression(2, 3, 1)
+  )
+})
+
+test_that("parse_safe works with multi expressions", {
+  expect_equal(
+    parse_safe(c(" \n", "\n ", " \n  \n  ")),
+    expression(NA, NA, NA)
+  )
+
+  expect_equal(
+    parse_safe(c("alpha ~ beta", "beta \n gamma", "")),
+    expression(alpha ~ beta, beta, NA)
+  )
+
+  expect_equal(
+    parse_safe(c("alpha ~ beta", " ", "integral(f(x) * dx, a, b)")),
+    expression(alpha ~ beta, NA, integral(f(x) * dx, a, b))
+  )
+
+  expect_equal(
+    parse_safe(c(NA, 1, 2, "a \n b")),
+    expression(NA, 1, 2, a)
+  )
+})

From aa00e13efa74ed454a5a73aa5f89ef6f0acd1784 Mon Sep 17 00:00:00 2001
From: Kamil Slowikowski <kslowikowski@gmail.com>
Date: Sun, 2 Sep 2018 22:04:51 -0400
Subject: [PATCH 07/18] change parse_safe(text = x) to parse_safe(x)

---
 R/geom-label.R | 2 +-
 R/geom-text.r  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/R/geom-label.R b/R/geom-label.R
index 3a1d3250b5..ac83f4e7f8 100644
--- a/R/geom-label.R
+++ b/R/geom-label.R
@@ -63,7 +63,7 @@ GeomLabel <- ggproto("GeomLabel", Geom,
                         label.size = 0.25) {
     lab <- data$label
     if (parse) {
-      lab <- parse_safe(text = as.character(lab))
+      lab <- parse_safe(as.character(lab))
     }
 
     data <- coord$transform(data, panel_params)
diff --git a/R/geom-text.r b/R/geom-text.r
index 88be5c721d..6988c924ea 100644
--- a/R/geom-text.r
+++ b/R/geom-text.r
@@ -175,7 +175,7 @@ GeomText <- ggproto("GeomText", Geom,
                         na.rm = FALSE, check_overlap = FALSE) {
     lab <- data$label
     if (parse) {
-      lab <- parse_safe(text = as.character(lab))
+      lab <- parse_safe(as.character(lab))
     }
 
     data <- coord$transform(data, panel_params)

From 5a21915d33d4c583ea10204defef395049c442eb Mon Sep 17 00:00:00 2001
From: Kamil Slowikowski <kslowikowski@gmail.com>
Date: Mon, 3 Sep 2018 11:08:20 -0400
Subject: [PATCH 08/18] modify comment for parse_safe()

add URL to GitHub issue #2864
---
 R/utilities.r | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/R/utilities.r b/R/utilities.r
index d8d214768b..da2979b3dc 100644
--- a/R/utilities.r
+++ b/R/utilities.r
@@ -431,18 +431,15 @@ is_column_vec <- function(x) {
   length(dims) == 2L && dims[[2]] == 1L
 }
 
-#' Parse a vector of expressions without silently dropping any items.
-#'
-#' Note that `parse(text = NULL)` does not work and should be avoided.
-#'
-#' For more discussion, see #2864
-#'
-#' @keywords internal
-#' @examples
-#' length(parse(text = c("alpha", "", "gamma")))
-#' #> 2
-#' length(parse_safe(text = c("alpha", "", "gamma")))
-#' #> 3
+# Parse takes takes n strings and returns n expressions
+# See https://github.com/tidyverse/ggplot2/issues/2864 for discussion
+#
+# parse(text = c("alpha", "", "gamma"))
+# #> expression(alpha, gamma)
+#
+# parse_safe(text = c("alpha", "", "gamma"))
+# #> expression(alpha, NA, gamma)
+#
 parse_safe <- function(text) {
   out <- vector("expression", length(text))
   for (i in seq_along(text)) {

From f65ea714fceddb8497c545919b8971c075a71bfe Mon Sep 17 00:00:00 2001
From: Kamil Slowikowski <kslowikowski@gmail.com>
Date: Mon, 3 Sep 2018 11:28:02 -0400
Subject: [PATCH 09/18] fix parsing degree labels in geom_sf()

---
 R/sf.R | 33 +++++++++++++++++----------------
 1 file changed, 17 insertions(+), 16 deletions(-)

diff --git a/R/sf.R b/R/sf.R
index b2e76abf0b..65d57b206a 100644
--- a/R/sf.R
+++ b/R/sf.R
@@ -507,6 +507,21 @@ CoordSf <- ggproto("CoordSf", CoordCartesian,
     graticule$y_start <- sf_rescale01_x(graticule$y_start, y_range)
     graticule$y_end <- sf_rescale01_x(graticule$y_end, y_range)
 
+    # Convert 'degree' to the degree symbol
+    parse_ids <- grepl("\\bdegree\\b", graticule$degree_label)
+    if (any(parse_ids)) {
+      graticule$degree_label <- Map(
+        function(parse_id, label) {
+          if (parse_id) {
+            parse(text = label)[[1]]
+          } else {
+            as.expression(label)[[1]]
+          }
+        },
+        parse_ids, graticule$degree_label
+      )
+    }
+
     list(
       x_range = x_range,
       y_range = y_range,
@@ -549,18 +564,11 @@ CoordSf <- ggproto("CoordSf", CoordCartesian,
     graticule <- panel_params$graticule
     east <- graticule[graticule$type == "E" & !is.na(graticule$degree_label), ]
 
-    labs <- east$degree_label
-
-    # parse labels into expressions if required
-    if (any(grepl("degree", labs))) {
-      labs <- parse_safe(as.character(labs))
-    }
-
     list(
       top = nullGrob(),
       bottom = guide_axis(
         east$x_start,
-        labs,
+        east$degree_label,
         position = "bottom",
         theme = theme
       )
@@ -571,17 +579,10 @@ CoordSf <- ggproto("CoordSf", CoordCartesian,
     graticule <- panel_params$graticule
     north <- graticule[graticule$type == "N" & !is.na(graticule$degree_label), ]
 
-    labs <- north$degree_label
-
-    # parse labels into expressions if required
-    if (any(grepl("degree", labs))) {
-      labs <- parse_safe(as.character(labs))
-    }
-
     list(
       left = guide_axis(
         north$y_start,
-        labs,
+        north$degree_label,
         position = "left",
         theme = theme
       ),

From f5a853fbf93f60c5864b92d92de7eaffb83de6f6 Mon Sep 17 00:00:00 2001
From: Kamil Slowikowski <kslowikowski@gmail.com>
Date: Mon, 3 Sep 2018 12:01:28 -0400
Subject: [PATCH 10/18] add news item about parse_safe()

---
 NEWS.md | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/NEWS.md b/NEWS.md
index f846db73a8..56a652429b 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -56,6 +56,11 @@
 *   `labs()` now has named arguments `title`, `subtitle`, `caption`, and `tag`.
     Also, `labs()` now accepts tidyeval (@yutannihilation, #2669).
 
+*   `geom_text(..., parse = TRUE)` now correctly renders the expected number of
+    items instead of silently dropping items that are not valid expressions.
+    This is also fixed for `geom_label()` and the axis labels for `geom_sf()`
+    (@slowkow, #2867).
+
 # ggplot2 3.0.0
 
 ## Breaking changes

From 2a089c09a64b12a3b5eb7fbb9b4536be458dc27d Mon Sep 17 00:00:00 2001
From: Kamil Slowikowski <kslowikowski@gmail.com>
Date: Mon, 3 Sep 2018 20:11:33 -0400
Subject: [PATCH 11/18] fix typo

---
 R/utilities.r | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/R/utilities.r b/R/utilities.r
index da2979b3dc..cb4fa74978 100644
--- a/R/utilities.r
+++ b/R/utilities.r
@@ -431,8 +431,8 @@ is_column_vec <- function(x) {
   length(dims) == 2L && dims[[2]] == 1L
 }
 
-# Parse takes takes n strings and returns n expressions
-# See https://github.com/tidyverse/ggplot2/issues/2864 for discussion
+# Parse takes n strings and returns n expressions.
+# See https://github.com/tidyverse/ggplot2/issues/2864 for discussion.
 #
 # parse(text = c("alpha", "", "gamma"))
 # #> expression(alpha, gamma)

From 66c92342215e4d61e6a969f5b3ff1e5e6e381662 Mon Sep 17 00:00:00 2001
From: Kamil Slowikowski <kslowikowski@gmail.com>
Date: Mon, 3 Sep 2018 20:15:14 -0400
Subject: [PATCH 12/18] move parse() into fixup_graticule_labels()

---
 R/sf.R | 30 +++++++++++++++---------------
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/R/sf.R b/R/sf.R
index 65d57b206a..75e33f2ab4 100644
--- a/R/sf.R
+++ b/R/sf.R
@@ -476,6 +476,21 @@ CoordSf <- ggproto("CoordSf", CoordCartesian,
     if (!is.null(graticule$plot12))
       graticule$degree_label[!graticule$plot12] <- NA
 
+    # Convert the string 'degree' to the degree symbol
+    parse_ids <- grepl("\\bdegree\\b", graticule$degree_label)
+    if (any(parse_ids)) {
+      graticule$degree_label <- Map(
+        function(parse_id, label) {
+          if (parse_id) {
+            parse(text = label)[[1]]
+          } else {
+            as.expression(label)[[1]]
+          }
+        },
+        parse_ids, graticule$degree_label
+      )
+    }
+
     graticule
   },
 
@@ -507,21 +522,6 @@ CoordSf <- ggproto("CoordSf", CoordCartesian,
     graticule$y_start <- sf_rescale01_x(graticule$y_start, y_range)
     graticule$y_end <- sf_rescale01_x(graticule$y_end, y_range)
 
-    # Convert 'degree' to the degree symbol
-    parse_ids <- grepl("\\bdegree\\b", graticule$degree_label)
-    if (any(parse_ids)) {
-      graticule$degree_label <- Map(
-        function(parse_id, label) {
-          if (parse_id) {
-            parse(text = label)[[1]]
-          } else {
-            as.expression(label)[[1]]
-          }
-        },
-        parse_ids, graticule$degree_label
-      )
-    }
-
     list(
       x_range = x_range,
       y_range = y_range,

From 8c798ee30b788f50f2078f4de665df74e90e463c Mon Sep 17 00:00:00 2001
From: Kamil Slowikowski <kslowikowski@gmail.com>
Date: Tue, 4 Sep 2018 09:00:57 -0400
Subject: [PATCH 13/18] change description of parse_safe()

---
 R/utilities.r | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/R/utilities.r b/R/utilities.r
index cb4fa74978..334b8a3a67 100644
--- a/R/utilities.r
+++ b/R/utilities.r
@@ -431,7 +431,7 @@ is_column_vec <- function(x) {
   length(dims) == 2L && dims[[2]] == 1L
 }
 
-# Parse takes n strings and returns n expressions.
+# Parse takes a vector of n lines and returns m expressions.
 # See https://github.com/tidyverse/ggplot2/issues/2864 for discussion.
 #
 # parse(text = c("alpha", "", "gamma"))

From 2b8b45975b1ede5a6517c483e3077d2b078d5a8b Mon Sep 17 00:00:00 2001
From: Kamil Slowikowski <kslowikowski@gmail.com>
Date: Tue, 4 Sep 2018 09:06:28 -0400
Subject: [PATCH 14/18] modify news item about parse_safe()

---
 NEWS.md | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/NEWS.md b/NEWS.md
index 1e954d6f67..2ed0d83a50 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -61,9 +61,9 @@
     (@clauswilke, #2733).
     
 *   `geom_text(..., parse = TRUE)` now correctly renders the expected number of
-    items instead of silently dropping items that are not valid expressions.
-    This is also fixed for `geom_label()` and the axis labels for `geom_sf()`
-    (@slowkow, #2867).
+    items instead of silently dropping items that are empty expressions, e.g.
+    the empty string "". This is also fixed for `geom_label()` and the axis
+    labels for `geom_sf()` (@slowkow, #2867).
 
 # ggplot2 3.0.0
 

From 637a88e7c7121ef44d9873c908aff3d9d8d05ebc Mon Sep 17 00:00:00 2001
From: Kamil Slowikowski <kslowikowski@gmail.com>
Date: Tue, 4 Sep 2018 09:07:51 -0400
Subject: [PATCH 15/18] add stopifnot() to parse_safe()

---
 R/utilities.r | 1 +
 1 file changed, 1 insertion(+)

diff --git a/R/utilities.r b/R/utilities.r
index 334b8a3a67..955e2d8ff9 100644
--- a/R/utilities.r
+++ b/R/utilities.r
@@ -441,6 +441,7 @@ is_column_vec <- function(x) {
 # #> expression(alpha, NA, gamma)
 #
 parse_safe <- function(text) {
+  stopifnot(is.character(text))
   out <- vector("expression", length(text))
   for (i in seq_along(text)) {
     expr <- parse(text = text[[i]])

From 95025cb2511bfba731496c1578da17178b50909c Mon Sep 17 00:00:00 2001
From: Kamil Slowikowski <kslowikowski@gmail.com>
Date: Tue, 4 Sep 2018 10:20:38 -0400
Subject: [PATCH 16/18] simplify parsing code in sf.R

---
 R/sf.R | 17 +++++------------
 1 file changed, 5 insertions(+), 12 deletions(-)

diff --git a/R/sf.R b/R/sf.R
index 75e33f2ab4..abcc60bceb 100644
--- a/R/sf.R
+++ b/R/sf.R
@@ -477,18 +477,11 @@ CoordSf <- ggproto("CoordSf", CoordCartesian,
       graticule$degree_label[!graticule$plot12] <- NA
 
     # Convert the string 'degree' to the degree symbol
-    parse_ids <- grepl("\\bdegree\\b", graticule$degree_label)
-    if (any(parse_ids)) {
-      graticule$degree_label <- Map(
-        function(parse_id, label) {
-          if (parse_id) {
-            parse(text = label)[[1]]
-          } else {
-            as.expression(label)[[1]]
-          }
-        },
-        parse_ids, graticule$degree_label
-      )
+    has_degree <- grepl("\\bdegree\\b", graticule$degree_label)
+    if (any(has_degree)) {
+      labels <- as.list(graticule$degree_label)
+      labels[has_degree] <- parse_safe(graticule$degree_label[has_degree])
+      graticule$degree_label <- labels
     }
 
     graticule

From 54d87c7fae26680435972a09f39341beddf977f7 Mon Sep 17 00:00:00 2001
From: Kamil Slowikowski <kslowikowski@gmail.com>
Date: Tue, 4 Sep 2018 10:24:09 -0400
Subject: [PATCH 17/18] improve news item about parse_safe()

---
 NEWS.md | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/NEWS.md b/NEWS.md
index 2ed0d83a50..7ec8955346 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -62,8 +62,9 @@
     
 *   `geom_text(..., parse = TRUE)` now correctly renders the expected number of
     items instead of silently dropping items that are empty expressions, e.g.
-    the empty string "". This is also fixed for `geom_label()` and the axis
-    labels for `geom_sf()` (@slowkow, #2867).
+    the empty string "". If an expression spans multiple lines, we take just
+    the first line and drop the rest. This same issue is also fixed for
+    `geom_label()` and the axis labels for `geom_sf()` (@slowkow, #2867).
 
 # ggplot2 3.0.0
 

From 06150624620faf4d57b50e729f6a1cb2b1b1439c Mon Sep 17 00:00:00 2001
From: Kamil Slowikowski <kslowikowski@gmail.com>
Date: Tue, 4 Sep 2018 10:40:54 -0400
Subject: [PATCH 18/18] do not test parse_safe(factor(...))

`parse_safe()` takes a character vector, not a factor
---
 tests/testthat/test-utilities.r | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/tests/testthat/test-utilities.r b/tests/testthat/test-utilities.r
index a98c6052b1..7ac5b32e3b 100644
--- a/tests/testthat/test-utilities.r
+++ b/tests/testthat/test-utilities.r
@@ -64,11 +64,6 @@ test_that("parse_safe works with simple expressions", {
     parse_safe(c(NA, "a", NA, "alpha")),
     expression(NA, a, NA, alpha)
   )
-
-  expect_equal(
-    parse_safe(factor(c("alpha", "beta", ""))),
-    expression(2, 3, 1)
-  )
 })
 
 test_that("parse_safe works with multi expressions", {