I’m saving a large data.table object as a compressed file using data.table::fwrite(data, 'data.csv.gz'). However, when I try to extract this file using Ubuntu file manager, I get an “empty archive error”. Extracting in the command line works (gunzip data.csv.gz).

Listing the gzip archive contents gives me a bogus compress ratio result (reprex bellow). Is this a bug on data.table::fwrite()?

library(data.table)

dt <- data.table(a = 1:100000,
                 b = runif(100000))

fwrite(dt, 'teste.csv.gz')
# Malformed Gzip file (see ratio)
# Ubuntu file manager can't extract it.
res <- system('gunzip -l teste.csv.gz', intern = TRUE)
res
#> [1] "         compressed        uncompressed  ratio uncompressed_name"
#> [2] "            1055898               85906 -1129.1% teste.csv"

# but I can extract the file if I use the command line
system('gunzip teste.csv.gz')

# and if I compress the file through the CLI it works (see ratio)
# and now Ubuntu file manager can handle the archive
system('gzip teste.csv')
res <- system('gunzip -l teste.csv.gz', intern = TRUE)
res
#> [1] "         compressed        uncompressed  ratio uncompressed_name"
#> [2] "            1054997             2388946  55.8% teste.csv"

sessionInfo()
#> R version 4.4.0 (2024-04-24)
#> Platform: x86_64-pc-linux-gnu
#> Running under: Ubuntu 20.04.6 LTS
#> 
#> Matrix products: default
#> BLAS:   /usr/lib/x86_64-linux-gnu/openblas-pthread/libblas.so.3 
#> LAPACK: /usr/lib/x86_64-linux-gnu/openblas-pthread/liblapack.so.3;  LAPACK version 3.9.0
#> 
#> locale:
#>  [1] LC_CTYPE=pt_BR.UTF-8       LC_NUMERIC=C              
#>  [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8    
#>  [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=C             
#>  [7] LC_PAPER=en_US.UTF-8       LC_NAME=C                 
#>  [9] LC_ADDRESS=C               LC_TELEPHONE=C            
#> [11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C       
#> 
#> time zone: America/Sao_Paulo
#> tzcode source: system (glibc)
#> 
#> attached base packages:
#> [1] stats     graphics  grDevices utils     datasets  methods   base     
#> 
#> other attached packages:
#> [1] data.table_1.15.4
#> 
#> loaded via a namespace (and not attached):
#>  [1] styler_1.10.3     digest_0.6.35     fastmap_1.2.0     xfun_0.44        
#>  [5] magrittr_2.0.3    glue_1.7.0        R.utils_2.12.3    knitr_1.47       
#>  [9] htmltools_0.5.8.1 rmarkdown_2.27    lifecycle_1.0.4   cli_3.6.2        
#> [13] R.methodsS3_1.8.2 vctrs_0.6.5       reprex_2.1.0      withr_3.0.0      
#> [17] compiler_4.4.0    R.oo_1.26.0       R.cache_0.16.0    purrr_1.0.2      
#> [21] rstudioapi_0.16.0 tools_4.4.0       evaluate_0.23     yaml_2.3.8       
#> [25] rlang_1.1.3       fs_1.6.4

^{Created on 2024-05-29 with reprex v2.1.0}