`archive_extract()` not working for files compress using `data.table::fwrite()`

[matthiasgomolka]

Hi!

I started working with archive but stumbled upon the following problem: When I compress a csv file into a *. csv.gz archive using data.table::fwrite() and then want to extract the archive using archive_extract(), I get an error (see the reprex).

When I compress the csv file via archive_write_files(), the extraction works without problems. Here is the reprex:

# load packages
library(archive)
#> Warning: package 'archive' was built under R version 4.0.5
library(data.table)
#> Warning: package 'data.table' was built under R version 4.0.5

# prepare example files
data(mtcars)

# write csv
tf <- tempfile(fileext = ".csv")
fwrite(mtcars, tf)

# compress csv to csv.gz
tf_gz = paste0(tf, ".gz")
archive_write_files(
    archive = tf_gz, 
    files = tf, 
    format = "zip",
    filter = "gzip"
)

# extracting the archive works
archive_extract(tf_gz, tempdir())

# clean up
file.remove(c(tf, tf_gz))
#> [1] TRUE TRUE

# write archive via data.table
fwrite(mtcars, tf_gz)

# extracting the archive does not work
archive_extract(tf_gz, tempdir())
#> Error: archive_extract.cpp:166 archive_read_next_header(): Missing type keyword in mtree specification

^{Created on 2022-02-03 by the reprex package (v2.0.1)}

Is archive made to extract all kinds of (supported) archives without any prior knowledge about the archives? This is what I'm actually looking for.

[gaborcsardi]

Seems like it could be a libarchive bug: https://github.com/libarchive/libarchive/issues/507 Maybe we could work around it by telling libarchive the format explicitly.