From 113144fa9b6c220baeb888bc631cc1e65b181d23 Mon Sep 17 00:00:00 2001
From: bersbersbers <12128514+bersbersbers@users.noreply.github.com>
Date: Sat, 19 Mar 2022 09:09:31 +0100
Subject: [PATCH 1/4] Test that quantiles are drawn at expected positions
 (#4654)

---
 tests/testthat/test-geom-violin.R | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/tests/testthat/test-geom-violin.R b/tests/testthat/test-geom-violin.R
index d9d81b135b..38c0581284 100644
--- a/tests/testthat/test-geom-violin.R
+++ b/tests/testthat/test-geom-violin.R
@@ -46,6 +46,17 @@ test_that("quantiles do not fail on zero-range data", {
   expect_equal(length(layer_grob(p)), 1)
 })
 
+test_that("quantiles are at expected positions at zero width", {
+  # Symmetric density with n components and zero middle:
+  # 50% quantile can be drawn anywhere as long as there is density 0
+  n <- 256
+  density <- c(rep(2, n / 4), rep(0, n / 2), rep(2, n / 4)) / n
+  density.data <- data_frame(y = (1:n) / n, density = density)
+  line <- create_quantile_segment_frame(density.data, 0.5)
+  y_idx <- which.min(abs(density.data$y - line$y[1]))
+  expect_equal(density[y_idx], 0)
+})
+
 
 # Visual tests ------------------------------------------------------------
 

From 47f978f6379766eb1c050e80e42498686271783d Mon Sep 17 00:00:00 2001
From: bersbersbers <12128514+bersbersbers@users.noreply.github.com>
Date: Fri, 29 Oct 2021 13:22:13 +0200
Subject: [PATCH 2/4] Fix warning in geom_violin with draw_quantiles

Fix "collapsing to unique 'x' values" warnings (#4654). Closes #4455
---
 R/geom-violin.r | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/R/geom-violin.r b/R/geom-violin.r
index fe8e710389..16371916aa 100644
--- a/R/geom-violin.r
+++ b/R/geom-violin.r
@@ -197,7 +197,7 @@ GeomViolin <- ggproto("GeomViolin", Geom,
 # Returns a data.frame with info needed to draw quantile segments.
 create_quantile_segment_frame <- function(data, draw_quantiles) {
   dens <- cumsum(data$density) / sum(data$density)
-  ecdf <- stats::approxfun(dens, data$y)
+  ecdf <- stats::approxfun(dens, data$y, ties = "ordered")
   ys <- ecdf(draw_quantiles) # these are all the y-values for quantiles
 
   # Get the violin bounds for the requested quantiles.

From a2dc66ea4cdf7e7edd1913c136c2af17c99314cf Mon Sep 17 00:00:00 2001
From: bersbersbers <12128514+bersbersbers@users.noreply.github.com>
Date: Sat, 19 Mar 2022 09:15:44 +0100
Subject: [PATCH 3/4] Test that quantiles do not issue warning (#4654)

---
 tests/testthat/test-geom-violin.R | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/tests/testthat/test-geom-violin.R b/tests/testthat/test-geom-violin.R
index 38c0581284..9b6b3b1429 100644
--- a/tests/testthat/test-geom-violin.R
+++ b/tests/testthat/test-geom-violin.R
@@ -57,6 +57,15 @@ test_that("quantiles are at expected positions at zero width", {
   expect_equal(density[y_idx], 0)
 })
 
+test_that("quantiles do not issue warning", {
+  data <- data_frame(x = 1, y = c(0, 0.25, 0.5, 0.75, 5))
+
+  p <- ggplot(data, aes(x = x, y = y)) +
+    geom_violin(draw_quantiles = 0.5)
+
+  expect_warning(plot(p), regexp = NA)
+})
+
 
 # Visual tests ------------------------------------------------------------
 

From 384607bc61248756257970f6e26bb1e066685e1e Mon Sep 17 00:00:00 2001
From: bersbersbers <12128514+bersbersbers@users.noreply.github.com>
Date: Sat, 19 Mar 2022 09:22:12 +0100
Subject: [PATCH 4/4] Update NEWS.md

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

diff --git a/NEWS.md b/NEWS.md
index 5733b1e4ef..b595f084fb 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,8 @@
 # ggplot2 (development version)
 
+* `geom_violin()` no longer issues "collapsing to unique 'x' values" warning
+  (@bersbersbers, #4455)
+
 * `annotate()` now documents unsupported geoms (`geom_abline()`, `geom_hline()`
   and `geom_vline()`), and warns when they are requested (@mikmart, #4719)