WISH: Clarify "BiocManager.check_repositories" message and silence it in more cases?

从 R/repositories.R 开始，尤其是查看 issue 中链接的 repository 检查代码，并阅读 ?BiocManager::repositories。比较消息条件、BiocManager.check_repositories 选项、接受的 repository，以及所要求的环境变量行为。当预期的消息、文档和静默行为达成一致并由适当的测试覆盖时，即视为完成。

Issue

It is not always clear why the following message appear:

'getOption("repos")' replaces Bioconductor standard repositories, see
'?repositories' for details
replacement repositories:
CRAN: https://cloud.r-project.org

For instance, it shows up in the middle of a package installation when checking on R-hub, e.g.

* installing *source* package 'pillar' ...
** package 'pillar' successfully unpacked and MD5 sums checked
** using staged installation
** R
** inst
** byte-compile and prepare package for lazy loading
'getOption("repos")' replaces Bioconductor standard repositories, see
'?repositories' for details
replacement repositories:
CRAN: https://cloud.r-project.org
** help
*** installing help indices
*** copying figures
** building package indices
'getOption("repos")' replaces Bioconductor standard repositories, see
'?repositories' for details
replacement repositories:
CRAN: https://cloud.r-project.org
** installing vignettes
** testing if installed package can be loaded from temporary location
'getOption("repos")' replaces Bioconductor standard repositories, see
'?repositories' for details
replacement repositories:
CRAN: https://cloud.r-project.org
** testing if installed package can be loaded from final location
'getOption("repos")' replaces Bioconductor standard repositories, see
'?repositories' for details
replacement repositories:
CRAN: https://cloud.r-project.org
** testing if installed package keeps a record of temporary installation path
* creating tarball
packaged installation of 'pillar' as 'pillar_1.8.1_R_x86_64-pc-linux-gnu.tar.gz'
* DONE (pillar)

Suggestions

Suggestion 1: Clarify help location

Improve the message to clarify in which package the help is from + use full stop and capitalize next sentence, e.g.

'getOption("repos")' replaces Bioconductor standard repositories, see
'?BiocManager::repositories' for details.
Replacement repositories:
CRAN: https://cloud.r-project.org

or even

'getOption("repos")' replaces Bioconductor standard repositories, see
'help("repositories", package = "BiocManager")' for details.
Replacement repositories:
CRAN: https://cloud.r-project.org

Suggestion 2: Explain why

It is also not clear from the message why it is shown. For example, does it try to warn me about something, and if so, why? Or is it just an FYI message?

Maybe the message itself can be improved, or the paragraph in ?BiocManager::repositories could be extended.

Suggestion 3: Is the help page up-to-date on this?

From

https://github.com/Bioconductor/BiocManager/blob/7e3f92cb78472051712571b070f155f4516fa23d/R/repositories.R#L21-L37

it looks like this is a message condition and not a warning condition. However, in ?BiocManager::repositories there is a mentioning of a "warning":

If alternative default repositories are known to provide appropriate versions of CRAN or Bioconductor packages, the warning may be silenced (displayed as a message) with options(BiocManager.check_repositories = FALSE).

Also, the end of the same paragraph says:

A message is still printed, to serve as a reminder when debugging problems related to incompatible package installation.

Is that correct? Looking at the code, it looks like the note is only generated if R option BiocManager.check_repositories is TRUE.

Suggestion 4: Add all known CRAN repositories to the acceptance list

Could https://cloud.r-project.org, and all other known CRAN mirrors:

> m <- getCRANmirrors(all = FALSE, local.only = FALSE)
> str(m)
'data.frame':	99 obs. of  9 variables:
 $ Name       : chr  "0-Cloud [https]" "Argentina (La Plata)" "Australia (Canberra) [https]" "Australia (Melbourne 1) [https]" ...
 $ Country    : chr  "0-Cloud" "Argentina" "Australia" "Australia" ...
 $ City       : chr  "0-Cloud" "La Plata" "Canberra" "Melbourne" ...
 $ URL        : chr  "https://cloud.r-project.org/" "http://mirror.fcaglp.unlp.edu.ar/CRAN/" "https://cran.csiro.au/" "https://mirror.aarnet.edu.au/pub/CRAN/" ...
 $ Host       : chr  "Automatic redirection to servers worldwide, currently sponsored by Rstudio" "Universidad Nacional de La Plata" "CSIRO" "AARNET" ...
 $ Maintainer : chr  "cran # rstudio.com" "esuarez # Fcaglp.unlp.edu.ar" "ben.tan # csiro.au, Jayesh.joshi # csiro.au, CSIROServiceDesk # csiro.au" "<sysadmin # aarnet.edu.au>" ...
 $ OK         : int  1 1 1 1 1 1 1 1 1 1 ...
 $ CountryCode: chr  "us" "ar" "au" "au" ...
 $ Comment    : chr  "secure_mirror_from_master" "" "secure_mirror_from_master" "secure_mirror_from_master" ...

be accepted by default (when not using a snapshot mirror)?

Suggestion 5: Add environment variable

Since the default can be quite noisy (e.g. R-hub and GitHub Actions), would it be possible to control R option BiocManager.check_repositories via a corresponding environment variable, e.g. R_BIOCMANAGER_CHECK_REPOSITORIES. That would make it possible to silence these messages from outside of R.