guides = 'collect' does not work with latest github version of ggplot2

[BenVolpe94]

Hi! I'm currently using the latest github version of ggplot2 because it has a fix for an issue I encountered. I noticed however that this version broke the guides = 'collect' option in patchwork.

See example below:

# Load current main branch
devtools::dev_mode(on = T)
#> ✔ Dev mode: ON
library(ggplot2)
library(patchwork)

# Create plots
p1 <- ggplot(mtcars) + 
  geom_point(aes(mpg, disp)) + 
  ggtitle('Plot 1')

p2 <- ggplot(mtcars) + 
  geom_boxplot(aes(gear, disp, group = gear)) + 
  ggtitle('Plot 2')

p3 <- ggplot(mtcars) + 
  geom_point(aes(hp, wt, colour = mpg)) + 
  ggtitle('Plot 3')

p4 <- ggplot(mtcars) + 
  geom_bar(aes(gear)) + 
  facet_wrap(~cyl) + 
  ggtitle('Plot 4')

# Combine plots
p1 + p2 + p3 + p4 +
  plot_layout(guides = 'collect')
#> Error in identicalUnits(x): object is not a unit

# Session info
sessionInfo()
#> R version 4.3.3 (2024-02-29 ucrt)
#> Platform: x86_64-w64-mingw32/x64 (64-bit)
#> Running under: Windows 11 x64 (build 22635)
#> 
#> Matrix products: default
#> 
#> 
#> locale:
#> [1] LC_COLLATE=Dutch_Belgium.utf8  LC_CTYPE=Dutch_Belgium.utf8   
#> [3] LC_MONETARY=Dutch_Belgium.utf8 LC_NUMERIC=C                  
#> [5] LC_TIME=Dutch_Belgium.utf8    
#> 
#> time zone: Europe/Brussels
#> tzcode source: internal
#> 
#> attached base packages:
#> [1] stats     graphics  grDevices utils     datasets  methods   base     
#> 
#> other attached packages:
#> [1] patchwork_1.2.0    ggplot2_3.5.1.9000
#> 
#> loaded via a namespace (and not attached):
#>  [1] utf8_1.2.4        generics_0.1.3    stringi_1.8.4     digest_0.6.36    
#>  [5] magrittr_2.0.3    evaluate_0.24.0   grid_4.3.3        pkgload_1.4.0    
#>  [9] fastmap_1.2.0     pkgbuild_1.4.4    sessioninfo_1.2.2 urlchecker_1.0.1 
#> [13] promises_1.3.0    purrr_1.0.2       fansi_1.0.6       scales_1.3.0     
#> [17] cli_3.6.3.9000    shiny_1.9.1       rlang_1.1.4       ellipsis_0.3.2   
#> [21] munsell_0.5.1     reprex_2.1.1      remotes_2.5.0     withr_3.0.1      
#> [25] cachem_1.1.0      yaml_2.3.10       devtools_2.4.5    tools_4.3.3      
#> [29] memoise_2.0.1     dplyr_1.1.4       colorspace_2.1-1  httpuv_1.6.15    
#> [33] vctrs_0.6.5       R6_2.5.1          mime_0.12         lifecycle_1.0.4  
#> [37] stringr_1.5.1     fs_1.6.4          htmlwidgets_1.6.4 usethis_3.0.0    
#> [41] miniUI_0.1.1.1    pkgconfig_2.0.3   pillar_1.9.0      later_1.3.2      
#> [45] gtable_0.3.5      glue_1.7.0        profvis_0.3.8     Rcpp_1.0.13      
#> [49] xfun_0.46         tibble_3.2.1      tidyselect_1.2.1  rstudioapi_0.16.0
#> [53] knitr_1.48        farver_2.1.2      xtable_1.8-4      htmltools_0.5.8.1
#> [57] labeling_0.4.3    rmarkdown_2.27    compiler_4.3.3

I get the following Traceback:

Error in identicalUnits(x) : object is not a unit
7. identicalUnits(x)
6. unit.c(legend.box.margin[4], widths, legend.box.margin[2])
5. guides_build(guides, theme)
4. assemble_guides(guide_grobs, theme)
3. build_patchwork(plot, plot$layout$guides %||% "auto")
2. print.patchwork(x)
1. (function (x, ...)
UseMethod("print"))(x)