pkg_system_requirements only reports direct sys reqs and ignores imports

[assignUser]

As I noticed in r-lib/actions#370 local_system_requirments and pkg_system_requirements seem to behave unxepectedly different. local recursively reports all system requirements of the package and its dependencies, while pkg only reports requirements listed directly in the DESCRIPTION of the package. I assume this is a bug?

pth <- fs::path_temp("testpackage")
usethis::create_package(pth, rstudio = FALSE, check_name = FALSE, fields = list(Imports = "gert"))
#> v Creating ...
setwd(pth)
pak::local_install()
#> i Loading metadata database
#> i Loading metadata database
pak::local_system_requirements(os = "ubuntu", os_release = "18.04")
#> [1] "apt-get install -y software-properties-common"
#> [2] "add-apt-repository -y ppa:cran/libgit2"       
#> [3] "apt-get update"                               
#> [4] "apt-get install -y libcurl4-openssl-dev"      
#> [5] "apt-get install -y libssl-dev"                
#> [6] "apt-get install -y git"                       
#> [7] "apt-get install -y libgit2-dev"
pak::pkg_system_requirements("testpackage", os = "ubuntu", os_release = "18.04")
#> character(0)

^{Created on 2021-09-06 by the reprex package (v2.0.1)}

[assignUser]

This seems to also cause pak::pkg_install to fail installation of e.g. devtools when dependencies have additional system requirements (in this case curl/openssl)

> pak::pkg_install("devtools")
                                                                           
→ Will install 38 packages.
→ Will update 12 packages.
.
.
.
ℹ Building curl 4.3.2                             
✖ Failed to build curl 4.3.2                      
Error: Failed to build source package 'curl'    

[riccardoporreca]

@assignUser, as far as I can understand, the two functions have intrinsically a different behavior in the way they use the RSPM API to retrieve system requirements (via pak:::system_requirements_internal()):

pkg_system_requirements() just calls the API for the given package name, and can only return sys reqs if the package is known to RSPM:

pak/R/system-requirements.R

Lines 64 to 75 in 7e4fdc7

	req_url <- sprintf(
	"%s/sysreqs?all=false&pkgname=%s&distribution=%s&release=%s",
	rspm_repo_url,
	package,
	os,
	os_release
	)
	res <- curl::curl_fetch_memory(req_url)
	data <- jsonlite::fromJSON(rawToChar(res$content), simplifyVector = FALSE)
	pre_install <- unique(unlist(c(data[["pre_install"]], lapply(data[["requirements"]], function(x) x[["requirements"]][["pre_install"]]))))
	install_scripts <- unique(unlist(c(data[["install_scripts"]], lapply(data[["requirements"]], function(x) x[["requirements"]][["install_scripts"]]))))

The API actually returns an error (https://packagemanager.rstudio.com/__api__/repos/1/sysreqs?all=false&pkgname=testpackage&distribution=ubuntu&release=18.04), which is however not really handled by pkg_system_requirements().

local_system_requirements() calls the API passing the DESCRIPTION file instead (from which the package dependencies are extracted and corresponding sys reqs returned):

pak/R/system-requirements.R

Lines 79 to 111 in 7e4fdc7

	desc_file <- normalizePath(file.path(root, "DESCRIPTION"), mustWork = FALSE)
	if (!file.exists(desc_file)) {
	stop("`", root, "` must contain a package.", call. = FALSE)
	}
	req_url <- sprintf(
	"%s/sysreqs?distribution=%s&release=%s&suggests=true",
	rspm_repo_url,
	os,
	os_release
	)
	h <- curl::new_handle()
	desc_size <- file.size(desc_file)
	desc_data <- readBin(desc_file, "raw", desc_size)
	curl::handle_setheaders(h,
	customrequest = "POST",
	"content-type" = "text/plain"
	)
	curl::handle_setopt(h,
	postfieldsize = desc_size,
	postfields = desc_data
	)
	res <- curl::curl_fetch_memory(req_url, h)
	data <- jsonlite::fromJSON(rawToChar(res$content), simplifyVector = FALSE)
	pre_install <- unique(unlist(c(data[["pre_install"]], lapply(data[["dependencies"]], `[[`, "pre_install"))))
	install_scripts <- unique(unlist(c(data[["install_scripts"]], lapply(data[["dependencies"]], `[[`, "install_scripts"))))

[assignUser]

@riccardoporreca thank you for your detailed answer. So my issue is kind of an edge case with a package that is not on CRAN/RSPM. I still think that the different behavior should be noted in the docs and pkg_system_requirements() should communicate API failures to the user to make troubleshooting easier.

[riccardoporreca]

I still think that the different behavior should be noted in the docs and pkg_system_requirements() should communicate API failures to the user to make troubleshooting easier.

@assignUser, see commits above, merged by PR #328

[assignUser]

@riccardoporreca Great, thank you!