Remove extraneous limit values with drop=TRUE

* issue introduced in tidyverse#4471
* potential solution for tidyverse#4534 and tidyverse#4511
* add extra tests

Author: banfai

NEWS.md

@@ -1,5 +1,8 @@
 # ggplot2 (development version)
 
+* Fixes issue introduced in #4471 with extra values supplied to manual scale
+  showing up in legend (@banfai, #4511, #4534)
+
 # ggplot2 3.3.5
 This is a very small release focusing on fixing a couple of untenable issues 
 that surfaced with the 3.3.4 release

R/scale-.r

@@ -496,7 +496,11 @@ Scale <- ggproto("Scale", NULL,
     } else if (is.function(self$limits)) {
       self$limits(self$range$range)
     } else {
-      self$limits
+      if (!is.null(self$drop) && self$drop && !is.null(self$range$range)) {
+        intersect(self$range$range, self$limits)
+      } else {
+        self$limits
+      }
     }
   },
 

tests/testthat/test-scale-manual.r

@@ -1,9 +1,13 @@
 context("scale_manual")
 
 test_that("names of values used in manual scales", {
-   s <- scale_colour_manual(values = c("8" = "c","4" = "a","6" = "b"))
-   s$train(c("4", "6", "8"))
-   expect_equal(s$map(c("4", "6", "8")), c("a", "b", "c"))
+   s1 <- scale_colour_manual(values = c("8" = "c", "4" = "a", "6" = "b"))
+   s1$train(c("4", "6", "8"))
+   expect_equal(s1$map(c("4", "6", "8")), c("a", "b", "c"))
+
+   s2 <- scale_colour_manual(values = c("8" = "c", "4" = "a", "6" = "b"), na.value = NA)
+   s2$train(c("4", "8"))
+   expect_equal(s2$map(c("4", "6", "8")), c("a", NA, "c"))
 })
 
 
@@ -87,13 +91,25 @@ test_that("unnamed values match breaks in manual scales", {
 })
 
 test_that("limits works (#3262)", {
-  # named charachter vector
+  # named character vector
   s1 <- scale_colour_manual(values = c("8" = "c", "4" = "a", "6" = "b"), limits = c("4", "8"), na.value = NA)
   s1$train(c("4", "6", "8"))
   expect_equal(s1$map(c("4", "6", "8")), c("a", NA, "c"))
 
-  # named charachter vector
+  # unnamed character vector
   s2 <- scale_colour_manual(values = c("c", "a", "b"), limits = c("4", "8"), na.value = NA)
   s2$train(c("4", "6", "8"))
   expect_equal(s2$map(c("4", "6", "8")), c("c", NA, "a"))
 })
+
+test_that("fewer values (#3451)", {
+  # named character vector
+  s1 <- scale_colour_manual(values = c("4" = "a", "8" = "c"), na.value = NA)
+  s1$train(c("4", "6", "8"))
+  expect_equal(s1$map(c("4", "6", "8")), c("a", NA, "c"))
+
+  # unnamed character vector
+  s2 <- scale_colour_manual(values = c("4", "8"), na.value = NA)
+  s2$train(c("4", "6", "8"))
+  expect_error(s2$map(c("4", "6", "8")), "Insufficient values")
+})