unzip() is overwritting file, even when using overwrite = FALSE - r

Question

saveRDS(1, tmp1 <- "test1.rds")
tmp3 <- tempfile(fileext = ".zip")
zip(tmp3, tmp1)
unlink(tmp1)
file.exists(tmp1) # FALSE
unzip(tmp3)
file.exists(tmp1) # TRUE
readRDS(tmp1) # 1
saveRDS(2, tmp1)
readRDS(tmp1) # 2
unzip(tmp3, overwrite = FALSE)
# Warning message:
# In unzip(tmp3, overwrite = FALSE) : not overwriting file './test1.rds
readRDS(tmp1) # 1
unlink(tmp1)
I was expecting the last readRDS(tmp1) to return 2, right?
Any thought?
PS: I'm on Linux CentOS 7, using R version 3.5.2.

Answer 1

I have confirmed that you are indeed facing a bug in R 3.5.2. I have checked on Centos 7.2 only
R 3.6.0
$ /usr/bin/R -f test2.r
R version 3.6.0 (2019-04-26) -- "Planting of a Tree"
Copyright (C) 2019 The R Foundation for Statistical Computing
Platform: x86_64-redhat-linux-gnu (64-bit)
R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.
Natural language support but running in an English locale
R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.
Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.
[Previously saved workspace restored]
During startup - Warning message:
Setting LC_CTYPE failed, using "C"
> saveRDS(1, tmp1 <- "test1.rds")
> tmp3 <- tempfile(fileext = ".zip")
> zip(tmp3, tmp1)
adding: test1.rds (deflated 2%)
> unlink(tmp1)
> file.exists(tmp1) # FALSE
[1] FALSE
>
> unzip(tmp3)
> file.exists(tmp1) # TRUE
[1] TRUE
> readRDS(tmp1) # 1
[1] 1
> saveRDS(2, tmp1)
> readRDS(tmp1) # 2
[1] 2
> unzip(tmp3, overwrite = FALSE)
Warning message:
In unzip(tmp3, overwrite = FALSE) : not overwriting file './test1.rds
> readRDS(tmp1) # 1
[1] 2
>
> unlink(tmp1)
>
R 3.5.2
$ R -f test2.r
R version 3.5.2 (2018-12-20) -- "Eggshell Igloo"
Copyright (C) 2018 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)
R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.
Natural language support but running in an English locale
R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.
Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.
[Previously saved workspace restored]
During startup - Warning message:
Setting LC_CTYPE failed, using "C"
> saveRDS(1, tmp1 <- "test1.rds")
> tmp3 <- tempfile(fileext = ".zip")
> zip(tmp3, tmp1)
adding: test1.rds (deflated 5%)
> unlink(tmp1)
> file.exists(tmp1) # FALSE
[1] FALSE
>
> unzip(tmp3)
> file.exists(tmp1) # TRUE
[1] TRUE
> readRDS(tmp1) # 1
[1] 1
> saveRDS(2, tmp1)
> readRDS(tmp1) # 2
[1] 2
> unzip(tmp3, overwrite = FALSE)
Warning message:
In unzip(tmp3, overwrite = FALSE) : not overwriting file './test1.rds
> readRDS(tmp1) # 1
[1] 1
>
> unlink(tmp1)
>