From 209d6b372d898e9cea159bc1f26c2b56d238aa54 Mon Sep 17 00:00:00 2001
From: dereckdemezquita <dereck@demezquita.com>
Date: Sun, 9 Apr 2023 10:46:40 -0500
Subject: [PATCH 01/16] Vlines and Hlines might sometimes be inexistant;
 ggplot2 allows this but plotly fails on merging empty data.frame.

---
 R/layers2traces.R | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/R/layers2traces.R b/R/layers2traces.R
index 5b110cd56e..f42ca2f599 100644
--- a/R/layers2traces.R
+++ b/R/layers2traces.R
@@ -445,7 +445,9 @@ to_basic.GeomHline <- function(data, prestats_data, layout, params, p, ...) {
     data = layout$layout, cols = paste0(x, c("_min", "_max")), values_to = x, names_to = "variable"
   ) 
   lay <- as.data.frame(lay)
-  data <- merge(lay[c("PANEL", x)], data, by = "PANEL")
+  if (nrow(data) != 0) {
+    data <- merge(lay[c("PANEL", x)], data, by = "PANEL")
+  }
   data[["x"]] <- data[[x]]
   data[["y"]] <- data$yintercept
   prefix_class(data, c("GeomHline", "GeomPath"))
@@ -462,7 +464,10 @@ to_basic.GeomVline <- function(data, prestats_data, layout, params, p, ...) {
     data = layout$layout, cols = paste0(y, c("_min", "_max")), values_to = y, names_to = "variable"
   ) 
   lay <- as.data.frame(lay)
-  data <- merge(lay[c("PANEL", y)], data, by = "PANEL")
+  # fix for #1947; applied to Hline as well
+  if (nrow(data) != 0) {
+    data <- merge(lay[c("PANEL", y)], data, by = "PANEL")
+  }
   data[["y"]] <- data[[y]]
   data[["x"]] <- data$xintercept
   prefix_class(data, c("GeomVline", "GeomPath"))

From dfd9835c07cb874efe71c9606a4e8546bb038320 Mon Sep 17 00:00:00 2001
From: dereckdemezquita <dereck@demezquita.com>
Date: Sun, 9 Apr 2023 11:13:35 -0500
Subject: [PATCH 02/16] Unit test for allowing empty vlines.

---
 .../test-geom-vline-hline-allow-none-1947.R   | 39 +++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 tests/testthat/test-geom-vline-hline-allow-none-1947.R

diff --git a/tests/testthat/test-geom-vline-hline-allow-none-1947.R b/tests/testthat/test-geom-vline-hline-allow-none-1947.R
new file mode 100644
index 0000000000..e9f9e919fc
--- /dev/null
+++ b/tests/testthat/test-geom-vline-hline-allow-none-1947.R
@@ -0,0 +1,39 @@
+
+test_that("geom_vline/geom_hline does not throw an error with ggplotly when no lines are found", {
+  # Prepare data
+  data <- data.table::data.table(gapminder::gapminder)
+  # Add year of interest for vertical lines
+  data[year == 2002, year_of_interest := "yoi"]
+
+  # Case 1: Vertical line by feeding data to it; this allows for programmatically setting many lines at different years
+  p1 <- ggplot2::ggplot(data, ggplot2::aes(x = year, y = lifeExp, colour = country)) +
+    ggplot2::geom_line() +
+    ggplot2::geom_vline(
+      ggplot2::aes(xintercept = year),
+      data = data[year_of_interest == "yoi", ],
+      colour = "yellow",
+      alpha = 0.75,
+      linewidth = 1.25,
+      linetype = "dashed"
+    ) +
+    ggplot2::theme(legend.position = "none")
+
+  # Case 2: No lines are found, ggplot2 accepts it and no error is thrown
+  p2 <- ggplot2::ggplot(data, ggplot2::aes(x = year, y = lifeExp, colour = country)) +
+    ggplot2::geom_line() +
+    ggplot2::geom_vline(
+      ggplot2::aes(xintercept = year),
+      data = data[year_of_interest == "some_not_found", ],
+      colour = "yellow",
+      alpha = 0.75,
+      linewidth = 1.25,
+      linetype = "dashed"
+    ) +
+    ggplot2::theme(legend.position = "none")
+
+  # Test that ggplotly does not throw an error for both cases
+  expect_error(plotly::ggplotly(p1), NA) # lines are found no error is thrown
+  # error:
+  # "Error in fix.by(by.y, y) : 'by' must specify a uniquely valid column"
+  expect_error(plotly::ggplotly(p2), "Error in fix.by") # no lines are found no error is thrown
+})

From 27bba16c0c4c79c7492f24d80a9018054b74607d Mon Sep 17 00:00:00 2001
From: dereckdemezquita <dereck@demezquita.com>
Date: Sun, 9 Apr 2023 11:21:19 -0500
Subject: [PATCH 03/16] Added horizontal line test.

---
 .../test-geom-vline-hline-allow-none-1947.R   | 42 ++++++++++++++++++-
 1 file changed, 40 insertions(+), 2 deletions(-)

diff --git a/tests/testthat/test-geom-vline-hline-allow-none-1947.R b/tests/testthat/test-geom-vline-hline-allow-none-1947.R
index e9f9e919fc..ddb52dc1b9 100644
--- a/tests/testthat/test-geom-vline-hline-allow-none-1947.R
+++ b/tests/testthat/test-geom-vline-hline-allow-none-1947.R
@@ -18,6 +18,9 @@ test_that("geom_vline/geom_hline does not throw an error with ggplotly when no l
     ) +
     ggplot2::theme(legend.position = "none")
 
+  # Test that ggplotly does not throw an error for both cases
+  expect_error(plotly::ggplotly(p1), NA) # lines are found no error is thrown
+
   # Case 2: No lines are found, ggplot2 accepts it and no error is thrown
   p2 <- ggplot2::ggplot(data, ggplot2::aes(x = year, y = lifeExp, colour = country)) +
     ggplot2::geom_line() +
@@ -31,9 +34,44 @@ test_that("geom_vline/geom_hline does not throw an error with ggplotly when no l
     ) +
     ggplot2::theme(legend.position = "none")
 
-  # Test that ggplotly does not throw an error for both cases
-  expect_error(plotly::ggplotly(p1), NA) # lines are found no error is thrown
   # error:
   # "Error in fix.by(by.y, y) : 'by' must specify a uniquely valid column"
   expect_error(plotly::ggplotly(p2), "Error in fix.by") # no lines are found no error is thrown
+
+  ## --------------------------------
+  # testing horizontal line
+  data[round(lifeExp, 0) == 50, val_of_interest := "voi"]
+
+  # horizontal line no error
+  p3 <- ggplot2::ggplot(data, ggplot2::aes(x = year, y = lifeExp, colour = country)) +
+    ggplot2::geom_line() +
+    ggplot2::geom_hline(
+      ggplot2::aes(yintercept = lifeExp),
+      data = data[val_of_interest == "voi", ],
+      colour = "pink",
+      alpha = 0.75,
+      linewidth = 1.25,
+      linetype = "dashed"
+    ) +
+    ggplot2::theme(legend.position = "none")
+
+  expect_error(plotly::ggplotly(p3), NA) # lines are found no error is thrown
+
+  # horizontal line not set; error
+  p4 <- ggplot2::ggplot(data, ggplot2::aes(x = year, y = lifeExp, colour = country)) +
+    ggplot2::geom_line() +
+    ggplot2::geom_hline(
+      ggplot2::aes(yintercept = lifeExp),
+      data = data[val_of_interest == "some_val_not_found", ],
+      colour = "pink",
+      alpha = 0.75,
+      linewidth = 1.25,
+      linetype = "dashed"
+    ) +
+    ggplot2::theme(legend.position = "none")
+
+  # ggplot2 allows this no error
+  # print(p4)
+  # "Error in fix.by(by.y, y) : 'by' must specify a uniquely valid column"
+  expect_error(plotly::ggplotly(p4), "Error in fix.by") # no lines are found no error is thrown
 })

From 609085500028784a7813afd880754cbc441f0d1d Mon Sep 17 00:00:00 2001
From: dereckdemezquita <dereck@demezquita.com>
Date: Mon, 10 Apr 2023 21:54:45 -0500
Subject: [PATCH 04/16] If data is greater than nrow 0; better data check.

---
 R/layers2traces.R | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/R/layers2traces.R b/R/layers2traces.R
index f42ca2f599..2a7c7dd4a4 100644
--- a/R/layers2traces.R
+++ b/R/layers2traces.R
@@ -445,7 +445,7 @@ to_basic.GeomHline <- function(data, prestats_data, layout, params, p, ...) {
     data = layout$layout, cols = paste0(x, c("_min", "_max")), values_to = x, names_to = "variable"
   ) 
   lay <- as.data.frame(lay)
-  if (nrow(data) != 0) {
+  if (nrow(data) > 0) {
     data <- merge(lay[c("PANEL", x)], data, by = "PANEL")
   }
   data[["x"]] <- data[[x]]
@@ -465,7 +465,7 @@ to_basic.GeomVline <- function(data, prestats_data, layout, params, p, ...) {
   ) 
   lay <- as.data.frame(lay)
   # fix for #1947; applied to Hline as well
-  if (nrow(data) != 0) {
+  if (nrow(data) > 0) {
     data <- merge(lay[c("PANEL", y)], data, by = "PANEL")
   }
   data[["y"]] <- data[[y]]

From d254419765b6b42d15d5459b057fc7691acc96b9 Mon Sep 17 00:00:00 2001
From: dereckdemezquita <dereck@demezquita.com>
Date: Mon, 10 Apr 2023 22:16:04 -0500
Subject: [PATCH 05/16] Simplified example data and corrected expected result
 in expect_error; will move code to test-ggplot-hline.R.

---
 .../test-geom-vline-hline-allow-none-1947.R   | 87 ++++++++-----------
 1 file changed, 37 insertions(+), 50 deletions(-)

diff --git a/tests/testthat/test-geom-vline-hline-allow-none-1947.R b/tests/testthat/test-geom-vline-hline-allow-none-1947.R
index ddb52dc1b9..1d4fa0cc44 100644
--- a/tests/testthat/test-geom-vline-hline-allow-none-1947.R
+++ b/tests/testthat/test-geom-vline-hline-allow-none-1947.R
@@ -1,77 +1,64 @@
 
 test_that("geom_vline/geom_hline does not throw an error with ggplotly when no lines are found", {
-  # Prepare data
-  data <- data.table::data.table(gapminder::gapminder)
-  # Add year of interest for vertical lines
-  data[year == 2002, year_of_interest := "yoi"]
+  set.seed(123)
+  x <- seq(0, 10, by = 1)
+  # random walk
+  y <- cumsum(rnorm(length(x), mean = 0, sd = 1))
+  df <- data.frame(x, y)
+  df$point_of_interest <- "not_poi"
+  df[df$x == 2, ]$point_of_interest <- "poi" # point of interest
 
   # Case 1: Vertical line by feeding data to it; this allows for programmatically setting many lines at different years
-  p1 <- ggplot2::ggplot(data, ggplot2::aes(x = year, y = lifeExp, colour = country)) +
-    ggplot2::geom_line() +
+  p1 <- ggplot2::ggplot(df) +
+    ggplot2::geom_line(ggplot2::aes(x = x, y = y)) +
     ggplot2::geom_vline(
-      ggplot2::aes(xintercept = year),
-      data = data[year_of_interest == "yoi", ],
-      colour = "yellow",
-      alpha = 0.75,
-      linewidth = 1.25,
-      linetype = "dashed"
-    ) +
-    ggplot2::theme(legend.position = "none")
+      ggplot2::aes(xintercept = x),
+      data = df[df$point_of_interest == "poi", ],
+      colour = "yellow"
+    )
 
   # Test that ggplotly does not throw an error for both cases
   expect_error(plotly::ggplotly(p1), NA) # lines are found no error is thrown
 
   # Case 2: No lines are found, ggplot2 accepts it and no error is thrown
-  p2 <- ggplot2::ggplot(data, ggplot2::aes(x = year, y = lifeExp, colour = country)) +
-    ggplot2::geom_line() +
+  p2 <- ggplot2::ggplot(df) +
+    ggplot2::geom_line(ggplot2::aes(x = x, y = y)) +
     ggplot2::geom_vline(
-      ggplot2::aes(xintercept = year),
-      data = data[year_of_interest == "some_not_found", ],
-      colour = "yellow",
-      alpha = 0.75,
-      linewidth = 1.25,
-      linetype = "dashed"
-    ) +
-    ggplot2::theme(legend.position = "none")
+      ggplot2::aes(xintercept = x),
+      data = df[df$point_of_interest == "something_not_matched", ],
+      colour = "yellow"
+    )
 
-  # error:
+  # error given without fix:
   # "Error in fix.by(by.y, y) : 'by' must specify a uniquely valid column"
-  expect_error(plotly::ggplotly(p2), "Error in fix.by") # no lines are found no error is thrown
+  expect_error(plotly::ggplotly(p2), NA) # no lines are found no error is thrown
 
   ## --------------------------------
   # testing horizontal line
-  data[round(lifeExp, 0) == 50, val_of_interest := "voi"]
+  df$value_of_interest <- "not_voi"
+  df[round(df$x, 0) == 2, ]$value_of_interest <- "voi" # value of interest
 
   # horizontal line no error
-  p3 <- ggplot2::ggplot(data, ggplot2::aes(x = year, y = lifeExp, colour = country)) +
-    ggplot2::geom_line() +
+  p3 <- ggplot2::ggplot(df) +
+    ggplot2::geom_line(ggplot2::aes(x = x, y = y)) +
     ggplot2::geom_hline(
-      ggplot2::aes(yintercept = lifeExp),
-      data = data[val_of_interest == "voi", ],
-      colour = "pink",
-      alpha = 0.75,
-      linewidth = 1.25,
-      linetype = "dashed"
-    ) +
-    ggplot2::theme(legend.position = "none")
+      ggplot2::aes(yintercept = x),
+      data = df[df$value_of_interest == "voi", ],
+      colour = "pink"
+    )
 
   expect_error(plotly::ggplotly(p3), NA) # lines are found no error is thrown
 
   # horizontal line not set; error
-  p4 <- ggplot2::ggplot(data, ggplot2::aes(x = year, y = lifeExp, colour = country)) +
-    ggplot2::geom_line() +
+  p4 <- ggplot2::ggplot(df) +
+    ggplot2::geom_line(ggplot2::aes(x = x, y = y)) +
     ggplot2::geom_hline(
-      ggplot2::aes(yintercept = lifeExp),
-      data = data[val_of_interest == "some_val_not_found", ],
-      colour = "pink",
-      alpha = 0.75,
-      linewidth = 1.25,
-      linetype = "dashed"
-    ) +
-    ggplot2::theme(legend.position = "none")
+      ggplot2::aes(yintercept = x),
+      data = df[df$value_of_interest == "something_not_matched", ],
+      colour = "pink"
+    )
 
-  # ggplot2 allows this no error
-  # print(p4)
+  # error given without fix:
   # "Error in fix.by(by.y, y) : 'by' must specify a uniquely valid column"
-  expect_error(plotly::ggplotly(p4), "Error in fix.by") # no lines are found no error is thrown
+  expect_error(plotly::ggplotly(p4), NA) # no lines are found no error is thrown
 })

From 9ca4b74284baf2600c7b57bcb1be8027be491d8d Mon Sep 17 00:00:00 2001
From: dereckdemezquita <dereck@demezquita.com>
Date: Mon, 10 Apr 2023 22:16:55 -0500
Subject: [PATCH 06/16] Tests with simplified data; did both cases succesful
 plot and what was previously failing.

---
 .../test-geom-vline-hline-allow-none-1947.R   | 64 ------------------
 tests/testthat/test-ggplot-hline.R            | 65 +++++++++++++++++++
 2 files changed, 65 insertions(+), 64 deletions(-)
 delete mode 100644 tests/testthat/test-geom-vline-hline-allow-none-1947.R

diff --git a/tests/testthat/test-geom-vline-hline-allow-none-1947.R b/tests/testthat/test-geom-vline-hline-allow-none-1947.R
deleted file mode 100644
index 1d4fa0cc44..0000000000
--- a/tests/testthat/test-geom-vline-hline-allow-none-1947.R
+++ /dev/null
@@ -1,64 +0,0 @@
-
-test_that("geom_vline/geom_hline does not throw an error with ggplotly when no lines are found", {
-  set.seed(123)
-  x <- seq(0, 10, by = 1)
-  # random walk
-  y <- cumsum(rnorm(length(x), mean = 0, sd = 1))
-  df <- data.frame(x, y)
-  df$point_of_interest <- "not_poi"
-  df[df$x == 2, ]$point_of_interest <- "poi" # point of interest
-
-  # Case 1: Vertical line by feeding data to it; this allows for programmatically setting many lines at different years
-  p1 <- ggplot2::ggplot(df) +
-    ggplot2::geom_line(ggplot2::aes(x = x, y = y)) +
-    ggplot2::geom_vline(
-      ggplot2::aes(xintercept = x),
-      data = df[df$point_of_interest == "poi", ],
-      colour = "yellow"
-    )
-
-  # Test that ggplotly does not throw an error for both cases
-  expect_error(plotly::ggplotly(p1), NA) # lines are found no error is thrown
-
-  # Case 2: No lines are found, ggplot2 accepts it and no error is thrown
-  p2 <- ggplot2::ggplot(df) +
-    ggplot2::geom_line(ggplot2::aes(x = x, y = y)) +
-    ggplot2::geom_vline(
-      ggplot2::aes(xintercept = x),
-      data = df[df$point_of_interest == "something_not_matched", ],
-      colour = "yellow"
-    )
-
-  # error given without fix:
-  # "Error in fix.by(by.y, y) : 'by' must specify a uniquely valid column"
-  expect_error(plotly::ggplotly(p2), NA) # no lines are found no error is thrown
-
-  ## --------------------------------
-  # testing horizontal line
-  df$value_of_interest <- "not_voi"
-  df[round(df$x, 0) == 2, ]$value_of_interest <- "voi" # value of interest
-
-  # horizontal line no error
-  p3 <- ggplot2::ggplot(df) +
-    ggplot2::geom_line(ggplot2::aes(x = x, y = y)) +
-    ggplot2::geom_hline(
-      ggplot2::aes(yintercept = x),
-      data = df[df$value_of_interest == "voi", ],
-      colour = "pink"
-    )
-
-  expect_error(plotly::ggplotly(p3), NA) # lines are found no error is thrown
-
-  # horizontal line not set; error
-  p4 <- ggplot2::ggplot(df) +
-    ggplot2::geom_line(ggplot2::aes(x = x, y = y)) +
-    ggplot2::geom_hline(
-      ggplot2::aes(yintercept = x),
-      data = df[df$value_of_interest == "something_not_matched", ],
-      colour = "pink"
-    )
-
-  # error given without fix:
-  # "Error in fix.by(by.y, y) : 'by' must specify a uniquely valid column"
-  expect_error(plotly::ggplotly(p4), NA) # no lines are found no error is thrown
-})
diff --git a/tests/testthat/test-ggplot-hline.R b/tests/testthat/test-ggplot-hline.R
index 9ed7af92a6..4bf34290f2 100644
--- a/tests/testthat/test-ggplot-hline.R
+++ b/tests/testthat/test-ggplot-hline.R
@@ -97,3 +97,68 @@ test_that("hline works with coord_flip", {
   expect_equivalent(l$data[[2]]$x, c(5, 5))
   expect_equivalent(l$data[[2]]$y, c(5.95, 6.05))
 })
+
+# fix for issue #1974 pull request #2252
+test_that("geom_vline/geom_hline does not throw an error with ggplotly when no lines are found", {
+  set.seed(123)
+  x <- seq(0, 10, by = 1)
+  # random walk
+  y <- cumsum(rnorm(length(x), mean = 0, sd = 1))
+  df <- data.frame(x, y)
+  df$point_of_interest <- "not_poi"
+  df[df$x == 2, ]$point_of_interest <- "poi" # point of interest
+
+  # Case 1: Vertical line by feeding data to it; this allows for programmatically setting many lines at different years
+  p1 <- ggplot2::ggplot(df) +
+    ggplot2::geom_line(ggplot2::aes(x = x, y = y)) +
+    ggplot2::geom_vline(
+      ggplot2::aes(xintercept = x),
+      data = df[df$point_of_interest == "poi", ],
+      colour = "yellow"
+    )
+
+  # Test that ggplotly does not throw an error for both cases
+  expect_error(plotly::ggplotly(p1), NA) # lines are found no error is thrown
+
+  # Case 2: No lines are found, ggplot2 accepts it and no error is thrown
+  p2 <- ggplot2::ggplot(df) +
+    ggplot2::geom_line(ggplot2::aes(x = x, y = y)) +
+    ggplot2::geom_vline(
+      ggplot2::aes(xintercept = x),
+      data = df[df$point_of_interest == "something_not_matched", ],
+      colour = "yellow"
+    )
+
+  # error given without fix:
+  # "Error in fix.by(by.y, y) : 'by' must specify a uniquely valid column"
+  expect_error(plotly::ggplotly(p2), NA) # no lines are found no error is thrown
+
+  ## --------------------------------
+  # testing horizontal line
+  df$value_of_interest <- "not_voi"
+  df[round(df$x, 0) == 2, ]$value_of_interest <- "voi" # value of interest
+
+  # horizontal line no error
+  p3 <- ggplot2::ggplot(df) +
+    ggplot2::geom_line(ggplot2::aes(x = x, y = y)) +
+    ggplot2::geom_hline(
+      ggplot2::aes(yintercept = x),
+      data = df[df$value_of_interest == "voi", ],
+      colour = "pink"
+    )
+
+  expect_error(plotly::ggplotly(p3), NA) # lines are found no error is thrown
+
+  # horizontal line not set; error
+  p4 <- ggplot2::ggplot(df) +
+    ggplot2::geom_line(ggplot2::aes(x = x, y = y)) +
+    ggplot2::geom_hline(
+      ggplot2::aes(yintercept = x),
+      data = df[df$value_of_interest == "something_not_matched", ],
+      colour = "pink"
+    )
+
+  # error given without fix:
+  # "Error in fix.by(by.y, y) : 'by' must specify a uniquely valid column"
+  expect_error(plotly::ggplotly(p4), NA) # no lines are found no error is thrown
+})

From 28bbbc4ee7879d392684b3c48b8de0c8991fac16 Mon Sep 17 00:00:00 2001
From: dereckdemezquita <dereck@demezquita.com>
Date: Sat, 15 Apr 2023 08:58:08 -0500
Subject: [PATCH 07/16] Separated tests into respective files;
 horizontal/vertical.

---
 tests/testthat/test-ggplot-hline.R | 30 ------------------------
 tests/testthat/test-ggplot-vline.R | 37 ++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+), 30 deletions(-)

diff --git a/tests/testthat/test-ggplot-hline.R b/tests/testthat/test-ggplot-hline.R
index 4bf34290f2..6a57c301d8 100644
--- a/tests/testthat/test-ggplot-hline.R
+++ b/tests/testthat/test-ggplot-hline.R
@@ -105,36 +105,6 @@ test_that("geom_vline/geom_hline does not throw an error with ggplotly when no l
   # random walk
   y <- cumsum(rnorm(length(x), mean = 0, sd = 1))
   df <- data.frame(x, y)
-  df$point_of_interest <- "not_poi"
-  df[df$x == 2, ]$point_of_interest <- "poi" # point of interest
-
-  # Case 1: Vertical line by feeding data to it; this allows for programmatically setting many lines at different years
-  p1 <- ggplot2::ggplot(df) +
-    ggplot2::geom_line(ggplot2::aes(x = x, y = y)) +
-    ggplot2::geom_vline(
-      ggplot2::aes(xintercept = x),
-      data = df[df$point_of_interest == "poi", ],
-      colour = "yellow"
-    )
-
-  # Test that ggplotly does not throw an error for both cases
-  expect_error(plotly::ggplotly(p1), NA) # lines are found no error is thrown
-
-  # Case 2: No lines are found, ggplot2 accepts it and no error is thrown
-  p2 <- ggplot2::ggplot(df) +
-    ggplot2::geom_line(ggplot2::aes(x = x, y = y)) +
-    ggplot2::geom_vline(
-      ggplot2::aes(xintercept = x),
-      data = df[df$point_of_interest == "something_not_matched", ],
-      colour = "yellow"
-    )
-
-  # error given without fix:
-  # "Error in fix.by(by.y, y) : 'by' must specify a uniquely valid column"
-  expect_error(plotly::ggplotly(p2), NA) # no lines are found no error is thrown
-
-  ## --------------------------------
-  # testing horizontal line
   df$value_of_interest <- "not_voi"
   df[round(df$x, 0) == 2, ]$value_of_interest <- "voi" # value of interest
 
diff --git a/tests/testthat/test-ggplot-vline.R b/tests/testthat/test-ggplot-vline.R
index ceda7e1dfa..406b957956 100644
--- a/tests/testthat/test-ggplot-vline.R
+++ b/tests/testthat/test-ggplot-vline.R
@@ -46,3 +46,40 @@ test_that("vline works with coord_flip", {
   expect_equivalent(l$data[[2]]$x, c(5.95, 6.05))
   expect_equivalent(l$data[[2]]$y, c(5, 5))
 })
+
+
+# fix for issue #1974 pull request #2252
+test_that("geom_vline/geom_hline does not throw an error with ggplotly when no lines are found", {
+  set.seed(123)
+  x <- seq(0, 10, by = 1)
+  # random walk
+  y <- cumsum(rnorm(length(x), mean = 0, sd = 1))
+  df <- data.frame(x, y)
+  df$point_of_interest <- "not_poi"
+  df[df$x == 2, ]$point_of_interest <- "poi" # point of interest
+
+  # Case 1: Vertical line by feeding data to it; this allows for programmatically setting many lines at different years
+  p1 <- ggplot2::ggplot(df) +
+    ggplot2::geom_line(ggplot2::aes(x = x, y = y)) +
+    ggplot2::geom_vline(
+      ggplot2::aes(xintercept = x),
+      data = df[df$point_of_interest == "poi", ],
+      colour = "yellow"
+    )
+
+  # Test that ggplotly does not throw an error for both cases
+  expect_error(plotly::ggplotly(p1), NA) # lines are found no error is thrown
+
+  # Case 2: No lines are found, ggplot2 accepts it and no error is thrown
+  p2 <- ggplot2::ggplot(df) +
+    ggplot2::geom_line(ggplot2::aes(x = x, y = y)) +
+    ggplot2::geom_vline(
+      ggplot2::aes(xintercept = x),
+      data = df[df$point_of_interest == "something_not_matched", ],
+      colour = "yellow"
+    )
+
+  # error given without fix:
+  # "Error in fix.by(by.y, y) : 'by' must specify a uniquely valid column"
+  expect_error(plotly::ggplotly(p2), NA) # no lines are found no error is thrown
+})

From 4be8e7f5d3f2e1cc425489a30bc5880885645db7 Mon Sep 17 00:00:00 2001
From: Dereck Mezquita <44912288+dereckdemezquita@users.noreply.github.com>
Date: Sat, 3 Jun 2023 09:35:07 -0500
Subject: [PATCH 08/16] Seed for reproducibility.

Co-authored-by: Carson Sievert <cpsievert1@gmail.com>
---
 tests/testthat/test-ggplot-vline.R | 1 -
 1 file changed, 1 deletion(-)

diff --git a/tests/testthat/test-ggplot-vline.R b/tests/testthat/test-ggplot-vline.R
index 406b957956..1685aca9af 100644
--- a/tests/testthat/test-ggplot-vline.R
+++ b/tests/testthat/test-ggplot-vline.R
@@ -50,7 +50,6 @@ test_that("vline works with coord_flip", {
 
 # fix for issue #1974 pull request #2252
 test_that("geom_vline/geom_hline does not throw an error with ggplotly when no lines are found", {
-  set.seed(123)
   x <- seq(0, 10, by = 1)
   # random walk
   y <- cumsum(rnorm(length(x), mean = 0, sd = 1))

From bbf07fe8152bb231a8600953e4198dd3bcbd30e9 Mon Sep 17 00:00:00 2001
From: Dereck Mezquita <44912288+dereckdemezquita@users.noreply.github.com>
Date: Sat, 3 Jun 2023 09:35:16 -0500
Subject: [PATCH 09/16] Seed for reproducibility.

Co-authored-by: Carson Sievert <cpsievert1@gmail.com>
---
 tests/testthat/test-ggplot-hline.R | 1 -
 1 file changed, 1 deletion(-)

diff --git a/tests/testthat/test-ggplot-hline.R b/tests/testthat/test-ggplot-hline.R
index 6a57c301d8..147a1bc928 100644
--- a/tests/testthat/test-ggplot-hline.R
+++ b/tests/testthat/test-ggplot-hline.R
@@ -100,7 +100,6 @@ test_that("hline works with coord_flip", {
 
 # fix for issue #1974 pull request #2252
 test_that("geom_vline/geom_hline does not throw an error with ggplotly when no lines are found", {
-  set.seed(123)
   x <- seq(0, 10, by = 1)
   # random walk
   y <- cumsum(rnorm(length(x), mean = 0, sd = 1))

From 333d311d3b22d638c6d030c2edcde737abc3ba84 Mon Sep 17 00:00:00 2001
From: Dereck Mezquita <44912288+dereckdemezquita@users.noreply.github.com>
Date: Sat, 3 Jun 2023 09:55:17 -0500
Subject: [PATCH 10/16] Simplify tests.

Co-authored-by: Carson Sievert <cpsievert1@gmail.com>
---
 tests/testthat/test-ggplot-hline.R | 33 ++----------------------------
 1 file changed, 2 insertions(+), 31 deletions(-)

diff --git a/tests/testthat/test-ggplot-hline.R b/tests/testthat/test-ggplot-hline.R
index 147a1bc928..ba41144e50 100644
--- a/tests/testthat/test-ggplot-hline.R
+++ b/tests/testthat/test-ggplot-hline.R
@@ -98,36 +98,7 @@ test_that("hline works with coord_flip", {
   expect_equivalent(l$data[[2]]$y, c(5.95, 6.05))
 })
 
-# fix for issue #1974 pull request #2252
 test_that("geom_vline/geom_hline does not throw an error with ggplotly when no lines are found", {
-  x <- seq(0, 10, by = 1)
-  # random walk
-  y <- cumsum(rnorm(length(x), mean = 0, sd = 1))
-  df <- data.frame(x, y)
-  df$value_of_interest <- "not_voi"
-  df[round(df$x, 0) == 2, ]$value_of_interest <- "voi" # value of interest
-
-  # horizontal line no error
-  p3 <- ggplot2::ggplot(df) +
-    ggplot2::geom_line(ggplot2::aes(x = x, y = y)) +
-    ggplot2::geom_hline(
-      ggplot2::aes(yintercept = x),
-      data = df[df$value_of_interest == "voi", ],
-      colour = "pink"
-    )
-
-  expect_error(plotly::ggplotly(p3), NA) # lines are found no error is thrown
-
-  # horizontal line not set; error
-  p4 <- ggplot2::ggplot(df) +
-    ggplot2::geom_line(ggplot2::aes(x = x, y = y)) +
-    ggplot2::geom_hline(
-      ggplot2::aes(yintercept = x),
-      data = df[df$value_of_interest == "something_not_matched", ],
-      colour = "pink"
-    )
-
-  # error given without fix:
-  # "Error in fix.by(by.y, y) : 'by' must specify a uniquely valid column"
-  expect_error(plotly::ggplotly(p4), NA) # no lines are found no error is thrown
+  p3 <- ggplot(df) + geom_hline(aes(yintercept = x), data = data.frame(x = 1)[F, , drop = FALSE])
+  expect_error(plotly::ggplotly(p3), NA)
 })

From 5bb68a904166f8d0769de71415f27900654692af Mon Sep 17 00:00:00 2001
From: dereckdemezquita <dereck@demezquita.com>
Date: Sat, 3 Jun 2023 10:03:06 -0500
Subject: [PATCH 11/16] Simplified test.

---
 tests/testthat/test-ggplot-vline.R | 35 ++----------------------------
 1 file changed, 2 insertions(+), 33 deletions(-)

diff --git a/tests/testthat/test-ggplot-vline.R b/tests/testthat/test-ggplot-vline.R
index 1685aca9af..0829974f1f 100644
--- a/tests/testthat/test-ggplot-vline.R
+++ b/tests/testthat/test-ggplot-vline.R
@@ -47,38 +47,7 @@ test_that("vline works with coord_flip", {
   expect_equivalent(l$data[[2]]$y, c(5, 5))
 })
 
-
-# fix for issue #1974 pull request #2252
 test_that("geom_vline/geom_hline does not throw an error with ggplotly when no lines are found", {
-  x <- seq(0, 10, by = 1)
-  # random walk
-  y <- cumsum(rnorm(length(x), mean = 0, sd = 1))
-  df <- data.frame(x, y)
-  df$point_of_interest <- "not_poi"
-  df[df$x == 2, ]$point_of_interest <- "poi" # point of interest
-
-  # Case 1: Vertical line by feeding data to it; this allows for programmatically setting many lines at different years
-  p1 <- ggplot2::ggplot(df) +
-    ggplot2::geom_line(ggplot2::aes(x = x, y = y)) +
-    ggplot2::geom_vline(
-      ggplot2::aes(xintercept = x),
-      data = df[df$point_of_interest == "poi", ],
-      colour = "yellow"
-    )
-
-  # Test that ggplotly does not throw an error for both cases
-  expect_error(plotly::ggplotly(p1), NA) # lines are found no error is thrown
-
-  # Case 2: No lines are found, ggplot2 accepts it and no error is thrown
-  p2 <- ggplot2::ggplot(df) +
-    ggplot2::geom_line(ggplot2::aes(x = x, y = y)) +
-    ggplot2::geom_vline(
-      ggplot2::aes(xintercept = x),
-      data = df[df$point_of_interest == "something_not_matched", ],
-      colour = "yellow"
-    )
-
-  # error given without fix:
-  # "Error in fix.by(by.y, y) : 'by' must specify a uniquely valid column"
-  expect_error(plotly::ggplotly(p2), NA) # no lines are found no error is thrown
+  p <- ggplot(df) + geom_vline(aes(xintercept = x), data = data.frame(x = 1)[F, , drop = FALSE])
+  expect_error(plotly::ggplotly(p), NA)
 })

From ca4ccd58e4b8d0cfc65dff62bc5d64da27181d80 Mon Sep 17 00:00:00 2001
From: Dereck Mezquita <44912288+dereckdemezquita@users.noreply.github.com>
Date: Sat, 3 Jun 2023 10:08:01 -0500
Subject: [PATCH 12/16] Unnecessary comment.

Co-authored-by: Carson Sievert <cpsievert1@gmail.com>
---
 R/layers2traces.R | 1 -
 1 file changed, 1 deletion(-)

diff --git a/R/layers2traces.R b/R/layers2traces.R
index 2a7c7dd4a4..7757f94319 100644
--- a/R/layers2traces.R
+++ b/R/layers2traces.R
@@ -464,7 +464,6 @@ to_basic.GeomVline <- function(data, prestats_data, layout, params, p, ...) {
     data = layout$layout, cols = paste0(y, c("_min", "_max")), values_to = y, names_to = "variable"
   ) 
   lay <- as.data.frame(lay)
-  # fix for #1947; applied to Hline as well
   if (nrow(data) > 0) {
     data <- merge(lay[c("PANEL", y)], data, by = "PANEL")
   }

From 49dda5c773ad965cc4d97bb55d07b59354aa2b2b Mon Sep 17 00:00:00 2001
From: dereckdemezquita <dereck@demezquita.com>
Date: Sat, 3 Jun 2023 10:14:33 -0500
Subject: [PATCH 13/16] vline/hline empty df news fix.

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

diff --git a/NEWS.md b/NEWS.md
index 0468fe30be..9fb4dbaae8 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -12,6 +12,7 @@
 * Closed #2208: `ggplotly()` no longer errors given a `geom_area()` with 1 or less data points (error introduced by new behavior in ggplot2 v3.4.0). (#2209)
 * Closed #2220: `ggplotly()` no longer errors on `stat_summary(geom = "crossbar")`. (#2222)
 * Closed #2212: `ggplotly()` no longer removes legends when setting guide properties via `guides(aes = guide_xxx(...))`.
+* Closed #1947: `ggplotly()` now correctly handles `geom_vline` with empty data. Previously, if `geom_vline` was passed an empty data frame, it would result in an error. The plot is drawn even if no lines are found; this is the same behaviour as `ggplot2`. (#1947)
 
 # 4.10.1
 

From 19a65ea5502d22f199fd0c1c62087af6272975bf Mon Sep 17 00:00:00 2001
From: dereckdemezquita <dereck@demezquita.com>
Date: Sat, 3 Jun 2023 10:15:46 -0500
Subject: [PATCH 14/16] Issue closes both functione errors.

---
 NEWS.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/NEWS.md b/NEWS.md
index 9fb4dbaae8..0e0d844031 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -12,7 +12,7 @@
 * Closed #2208: `ggplotly()` no longer errors given a `geom_area()` with 1 or less data points (error introduced by new behavior in ggplot2 v3.4.0). (#2209)
 * Closed #2220: `ggplotly()` no longer errors on `stat_summary(geom = "crossbar")`. (#2222)
 * Closed #2212: `ggplotly()` no longer removes legends when setting guide properties via `guides(aes = guide_xxx(...))`.
-* Closed #1947: `ggplotly()` now correctly handles `geom_vline` with empty data. Previously, if `geom_vline` was passed an empty data frame, it would result in an error. The plot is drawn even if no lines are found; this is the same behaviour as `ggplot2`. (#1947)
+* Closed #1947: `ggplotly()` now correctly handles `geom_vline`/`geom_hline` with empty data. Previously, if `geom_vline`/`geom_hline` was passed an empty data frame, it would result in an error. The plot is drawn even if no lines are found; this is the same behaviour as `ggplot2`. (#1947)
 
 # 4.10.1
 

From 95cbcbd2ef719d64ec4236c911bd97d59d974635 Mon Sep 17 00:00:00 2001
From: dereckdemezquita <dereck@demezquita.com>
Date: Sat, 3 Jun 2023 10:17:01 -0500
Subject: [PATCH 15/16] American English!

---
 NEWS.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/NEWS.md b/NEWS.md
index 0e0d844031..9236172314 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -12,7 +12,7 @@
 * Closed #2208: `ggplotly()` no longer errors given a `geom_area()` with 1 or less data points (error introduced by new behavior in ggplot2 v3.4.0). (#2209)
 * Closed #2220: `ggplotly()` no longer errors on `stat_summary(geom = "crossbar")`. (#2222)
 * Closed #2212: `ggplotly()` no longer removes legends when setting guide properties via `guides(aes = guide_xxx(...))`.
-* Closed #1947: `ggplotly()` now correctly handles `geom_vline`/`geom_hline` with empty data. Previously, if `geom_vline`/`geom_hline` was passed an empty data frame, it would result in an error. The plot is drawn even if no lines are found; this is the same behaviour as `ggplot2`. (#1947)
+* Closed #1947: `ggplotly()` now correctly handles `geom_vline`/`geom_hline` with empty data. Previously, if `geom_vline`/`geom_hline` was passed an empty data frame, it would result in an error. The plot is drawn even if no lines are found; this is the same behavior as `ggplot2`. (#1947)
 
 # 4.10.1
 

From 76b5b387a221a215d38a9330615fe096c61c0712 Mon Sep 17 00:00:00 2001
From: dereckdemezquita <dereck@demezquita.com>
Date: Sat, 3 Jun 2023 10:17:36 -0500
Subject: [PATCH 16/16] Don't need number at the ned.

---
 NEWS.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/NEWS.md b/NEWS.md
index 9236172314..4e0cfd14f2 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -12,7 +12,7 @@
 * Closed #2208: `ggplotly()` no longer errors given a `geom_area()` with 1 or less data points (error introduced by new behavior in ggplot2 v3.4.0). (#2209)
 * Closed #2220: `ggplotly()` no longer errors on `stat_summary(geom = "crossbar")`. (#2222)
 * Closed #2212: `ggplotly()` no longer removes legends when setting guide properties via `guides(aes = guide_xxx(...))`.
-* Closed #1947: `ggplotly()` now correctly handles `geom_vline`/`geom_hline` with empty data. Previously, if `geom_vline`/`geom_hline` was passed an empty data frame, it would result in an error. The plot is drawn even if no lines are found; this is the same behavior as `ggplot2`. (#1947)
+* Closed #1947: `ggplotly()` now correctly handles `geom_vline`/`geom_hline` with empty data. Previously, if `geom_vline`/`geom_hline` was passed an empty data frame, it would result in an error. The plot is drawn even if no lines are found; this is the same behavior as `ggplot2`.
 
 # 4.10.1