Unused levels persist in legends from version 3.3.4

[wjakethompson]

It appears a bug was introduced in version 3.3.4. When using scale_fill_manual(), unused levels persist in the legend. Here is some example data.

library(tidyverse)

set.seed(123)
dat <- tibble(var = paste("Group", 1:9),
              val = runif(9),
              grp = sample(LETTERS[1:4], 9, replace = TRUE))

When all levels are present, things work as expected:

dat %>%
  ggplot(aes(x = val, y = var)) +
  geom_col(aes(fill = grp)) +
  scale_fill_manual(values = c("A" = "red", "B" = "blue", "C" = "orange",
                               "D" = "black"))

But when grp = "C" is no longer in the data, that value still persists in the legend.

dat %>%
  filter(grp != "C") %>%
  ggplot(aes(x = val, y = var)) +
  geom_col(aes(fill = grp)) +
  scale_fill_manual(values = c("A" = "red", "B" = "blue", "C" = "orange",
                               "D" = "black"))

From this thread on StackOverflow, it appears that this worked as expected in version 3.3.3. I have tested version 3.3.4 and the development version from GitHub, and the unused level persists in the legend for both.

^{Created on 2021-07-06 by the reprex package (v2.0.0)}

Session info

sessioninfo::session_info()
#> ─ Session info ───────────────────────────────────────────────────────────────
#>  setting  value                       
#>  version  R version 4.1.0 (2021-05-18)
#>  os       macOS Big Sur 10.16         
#>  system   x86_64, darwin17.0          
#>  ui       X11                         
#>  language (EN)                        
#>  collate  en_US.UTF-8                 
#>  ctype    en_US.UTF-8                 
#>  tz       America/Chicago             
#>  date     2021-07-06                  
#> 
#> ─ Packages ───────────────────────────────────────────────────────────────────
#>  package     * version    date       lib source                            
#>  assertthat    0.2.1      2019-03-21 [1] CRAN (R 4.1.0)                    
#>  backports     1.2.1      2020-12-09 [1] standard (@1.2.1)                 
#>  broom         0.7.7      2021-06-13 [1] standard (@0.7.7)                 
#>  cellranger    1.1.0      2016-07-27 [1] standard (@1.1.0)                 
#>  cli           3.0.0      2021-06-30 [1] CRAN (R 4.1.0)                    
#>  colorspace    2.0-2      2021-06-24 [1] CRAN (R 4.1.0)                    
#>  crayon        1.4.1      2021-02-08 [1] CRAN (R 4.1.0)                    
#>  curl          4.3.1      2021-04-30 [1] CRAN (R 4.1.0)                    
#>  DBI           1.1.1      2021-01-15 [1] standard (@1.1.1)                 
#>  dbplyr        2.1.1      2021-04-06 [1] standard (@2.1.1)                 
#>  digest        0.6.27     2020-10-24 [1] CRAN (R 4.1.0)                    
#>  dplyr       * 1.0.6      2021-05-05 [1] standard (@1.0.6)                 
#>  ellipsis      0.3.2      2021-04-29 [1] CRAN (R 4.1.0)                    
#>  evaluate      0.14       2019-05-28 [1] standard (@0.14)                  
#>  fansi         0.5.0      2021-05-25 [1] CRAN (R 4.1.0)                    
#>  farver        2.1.0      2021-02-28 [1] standard (@2.1.0)                 
#>  forcats     * 0.5.1      2021-01-27 [1] standard (@0.5.1)                 
#>  fs            1.5.0      2020-07-31 [1] standard (@1.5.0)                 
#>  generics      0.1.0      2020-10-31 [1] standard (@0.1.0)                 
#>  ggplot2     * 3.3.5.9000 2021-07-07 [1] Github (tidyverse/ggplot2@acaa98e)
#>  glue          1.4.2      2020-08-27 [1] CRAN (R 4.1.0)                    
#>  gtable        0.3.0      2019-03-25 [1] standard (@0.3.0)                 
#>  haven         2.4.1      2021-04-23 [1] standard (@2.4.1)                 
#>  highr         0.9        2021-04-16 [1] standard (@0.9)                   
#>  hms           1.1.0      2021-05-17 [1] CRAN (R 4.1.0)                    
#>  htmltools     0.5.1.1    2021-01-22 [1] standard (@0.5.1.1)               
#>  httr          1.4.2      2020-07-20 [1] standard (@1.4.2)                 
#>  jsonlite      1.7.2      2020-12-09 [1] CRAN (R 4.1.0)                    
#>  knitr         1.33       2021-04-24 [1] standard (@1.33)                  
#>  labeling      0.4.2      2020-10-20 [1] standard (@0.4.2)                 
#>  lifecycle     1.0.0      2021-02-15 [1] CRAN (R 4.1.0)                    
#>  lubridate     1.7.10     2021-02-26 [1] standard (@1.7.10)                
#>  magrittr      2.0.1      2020-11-17 [1] CRAN (R 4.1.0)                    
#>  mime          0.10       2021-02-13 [1] standard (@0.10)                  
#>  modelr        0.1.8      2020-05-19 [1] standard (@0.1.8)                 
#>  munsell       0.5.0      2018-06-12 [1] standard (@0.5.0)                 
#>  pillar        1.6.1      2021-05-16 [1] CRAN (R 4.1.0)                    
#>  pkgconfig     2.0.3      2019-09-22 [1] CRAN (R 4.1.0)                    
#>  purrr       * 0.3.4      2020-04-17 [1] standard (@0.3.4)                 
#>  R6            2.5.0      2020-10-28 [1] CRAN (R 4.1.0)                    
#>  Rcpp          1.0.6      2021-01-15 [1] standard (@1.0.6)                 
#>  readr       * 1.4.0      2020-10-05 [1] standard (@1.4.0)                 
#>  readxl        1.3.1      2019-03-13 [1] standard (@1.3.1)                 
#>  reprex        2.0.0      2021-04-02 [1] standard (@2.0.0)                 
#>  rlang         0.4.11     2021-04-30 [1] CRAN (R 4.1.0)                    
#>  rmarkdown     2.9        2021-06-15 [1] standard (@2.9)                   
#>  rstudioapi    0.13       2020-11-12 [1] standard (@0.13)                  
#>  rvest         1.0.0      2021-03-09 [1] standard (@1.0.0)                 
#>  scales        1.1.1      2020-05-11 [1] standard (@1.1.1)                 
#>  sessioninfo   1.1.1      2018-11-05 [1] standard (@1.1.1)                 
#>  stringi       1.6.2      2021-05-17 [1] CRAN (R 4.1.0)                    
#>  stringr     * 1.4.0      2019-02-10 [1] CRAN (R 4.1.0)                    
#>  styler        1.4.1      2021-03-30 [1] standard (@1.4.1)                 
#>  tibble      * 3.1.2      2021-05-16 [1] CRAN (R 4.1.0)                    
#>  tidyr       * 1.1.3      2021-03-03 [1] standard (@1.1.3)                 
#>  tidyselect    1.1.1      2021-04-30 [1] standard (@1.1.1)                 
#>  tidyverse   * 1.3.1      2021-04-15 [1] standard (@1.3.1)                 
#>  utf8          1.2.1      2021-03-12 [1] CRAN (R 4.1.0)                    
#>  vctrs         0.3.8      2021-04-29 [1] CRAN (R 4.1.0)                    
#>  withr         2.4.2      2021-04-18 [1] CRAN (R 4.1.0)                    
#>  xfun          0.24       2021-06-15 [1] standard (@0.24)                  
#>  xml2          1.3.2      2020-04-23 [1] CRAN (R 4.1.0)                    
#>  yaml          2.2.1      2020-02-01 [1] standard (@2.2.1)                 
#> 
#> [1] /Library/Frameworks/R.framework/Versions/4.1/Resources/library

[wjakethompson]

Should have searched better before posting. This appears to be a duplicate of #4534 and #4511.