[Rd] utils::unzip ignores overwrite argument, effectively

[Gábor Csárdi]

It does give a warning, but then it overwrites the files, anyway.
Reproducible example below.

This is R 3.4.3, but it does not seem to be fixed in R-devel:
https://github.com/wch/r-source/blob/4a9ca3e5ac6b19d7faa7c9290374f7604bf0ef64/src/main/dounzip.c#L171-L174

FYI,
Gábor

dir.create(tmp <- tempfile())
setwd(tmp)

cat("old1\n", file = "file1")
cat("old2\n", file = "file2")

utils::zip("files.zip", c("file1", "file2"))
#>   adding: file1 (stored 0%)
#>   adding: file2 (stored 0%)

unlink("file2")
cat("new1\n", file = "file1")
readLines("file1")
#> [1] "new1"

utils::unzip("files.zip", overwrite = FALSE)
#> Warning message:
#> In utils::unzip("files.zip", overwrite = FALSE) :
#>    not overwriting file './file1

readLines("file1")
#> [1] "old1"