`path_ext` wrong when two dots present

[tentacles-from-outer-space]

Two dots before file extension break path_ext:

path_ext("file..ext")
# [1] ""

[dicorynia]

Also when more than 2 dots...

library(fs)
test <- c("abc.xyz", "abc..xyz", "abc...xyz")
path_ext(test)
#> [1] "xyz" ""    ""

^{Created on 2023-01-31 with reprex v2.0.2}

Session info

sessionInfo()
#> R version 4.2.2 Patched (2022-11-10 r83330)
#> Platform: x86_64-pc-linux-gnu (64-bit)
#> Running under: Linux Mint 21.1
#> 
#> Matrix products: default
#> BLAS:   /usr/lib/x86_64-linux-gnu/blas/libblas.so.3.10.0
#> LAPACK: /usr/lib/x86_64-linux-gnu/lapack/liblapack.so.3.10.0
#> 
#> locale:
#>  [1] LC_CTYPE=fr_FR.UTF-8       LC_NUMERIC=C              
#>  [3] LC_TIME=fr_FR.UTF-8        LC_COLLATE=fr_FR.UTF-8    
#>  [5] LC_MONETARY=fr_FR.UTF-8    LC_MESSAGES=fr_FR.UTF-8   
#>  [7] LC_PAPER=fr_FR.UTF-8       LC_NAME=C                 
#>  [9] LC_ADDRESS=C               LC_TELEPHONE=C            
#> [11] LC_MEASUREMENT=fr_FR.UTF-8 LC_IDENTIFICATION=C       
#> 
#> attached base packages:
#> [1] stats     graphics  grDevices utils     datasets  methods   base     
#> 
#> other attached packages:
#> [1] fs_1.6.0
#> 
#> loaded via a namespace (and not attached):
#>  [1] digest_0.6.31   withr_2.5.0     lifecycle_1.0.3 reprex_2.0.2   
#>  [5] evaluate_0.20   rlang_1.0.6     cli_3.6.0       rstudioapi_0.14
#>  [9] rmarkdown_2.20  tools_4.2.2     glue_1.6.2      xfun_0.36      
#> [13] yaml_2.3.7      fastmap_1.1.0   compiler_4.2.2  htmltools_0.5.4
#> [17] knitr_1.42

[giocomai]

Encountered this in the wild with filenames in the format - "Surname + initial", e.g. for John Smith,

Smith, J..csv