Warning in install.packages : converting NULL pointer to R NULL

Hello,

R 4.0.0 on Ubuntu 20.04, sessionInfo() below.

Since I updated to R 4.0 that every time I try to install a package with
install.packages() the warning in the title shows up at the end, be the
installation successful or not. If it is successful, the package loads
with no problems, so I'm not very worried but it isn't normal (expected)
behavior, is it?

Here is a run of install.packages().


install.packages('cowplot')
Installing package into ?/usr/local/lib/R/site-library?
(as ?lib? is unspecified)
trying URL 'https://cloud.r-project.org/src/contrib/cowplot_1.0.0.tar.gz'
Content type 'application/x-gzip' length 1275585 bytes (1.2 MB)
==================================================
downloaded 1.2 MB

* installing *source* package ?cowplot? ...
** package ?cowplot? successfully unpacked and MD5 sums checked
** using staged installation
** R
** inst
** byte-compile and prepare package for lazy loading
** help
*** installing help indices
*** copying figures
** building package indices
** installing vignettes
** testing if installed package can be loaded from temporary location
** testing if installed package can be loaded from final location
** testing if installed package keeps a record of temporary installation
path
* DONE (cowplot)

The downloaded source packages are in
	?/tmp/Rtmp9NXQkt/downloaded_packages?
Warning in install.packages :
    converting NULL pointer to R NULL


Also, I'm running this on RStudio and haven't changed the R library
directory.


sessionInfo()
R version 4.0.0 (2020-04-24)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Ubuntu 20.04 LTS

Matrix products: default
BLAS:   /usr/lib/x86_64-linux-gnu/blas/libblas.so.3.9.0
LAPACK: /usr/lib/x86_64-linux-gnu/lapack/liblapack.so.3.9.0

locale:
   [1] LC_CTYPE=pt_PT.UTF-8       LC_NUMERIC=C
LC_TIME=pt_PT.UTF-8
   [4] LC_COLLATE=pt_PT.UTF-8     LC_MONETARY=pt_PT.UTF-8
LC_MESSAGES=pt_PT.UTF-8
   [7] LC_PAPER=pt_PT.UTF-8       LC_NAME=C                  LC_ADDRESS=C

[10] LC_TELEPHONE=C             LC_MEASUREMENT=pt_PT.UTF-8
LC_IDENTIFICATION=C

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

other attached packages:
[1] MASS_7.3-51.6  ggthemes_4.2.0 ggrepel_0.8.2  dplyr_0.8.5
ggplot2_3.3.0

loaded via a namespace (and not attached):
   [1] zoo_1.8-8          tidyselect_1.0.0   purrr_0.3.4
reshape2_1.4.4     haven_2.2.0
   [6] lattice_0.20-41    sodium_1.1         carData_3.0-3
colorspace_1.4-1   vctrs_0.2.4
[11] yaml_2.2.1         rlang_0.4.6        pillar_1.4.3
withr_2.2.0        foreign_0.8-79
[16] glue_1.4.0         readxl_1.3.1       lifecycle_0.2.0    plyr_1.8.6
          stringr_1.4.0
[21] MatrixModels_0.4-1 munsell_0.5.0      gtable_0.3.0
cellranger_1.1.0   zip_2.0.4
[26] rio_0.5.16         forcats_0.5.0      SparseM_1.78
quantreg_5.55      curl_4.3
[31] tis_1.38           Rcpp_1.0.4.6       readr_1.3.1
scales_1.1.0       abind_1.4-5
[36] farver_2.0.3       sos_2.0-0          brew_1.0-6
digest_0.6.25      hms_0.5.3
[41] png_0.1-7          stringi_1.4.6      openxlsx_4.1.4     grid_4.0.0
          tools_4.0.0
[46] magrittr_1.5       tibble_3.0.1       pacman_0.5.1
crayon_1.3.4       car_3.0-7
[51] pkgconfig_2.0.3    ellipsis_0.3.0     Matrix_1.2-18
data.table_1.12.8  assertthat_0.2.1
[56] httr_1.4.1         rstudioapi_0.11    R6_2.4.1
compiler_4.0.0


Thanks in advance,

Rui Barradas