Consider directly querying the lockfile for dependencies

[fkohrt]

Currently, we obtain the list of R package dependencies in three instances:

Add Code

code-publishing/code.qmd

Lines 157 to 180 in 1e6b034

	R packages that you use in your analysis are an obvious example of dependencies.
	Their version is recorded by `renv`,
	but you also need to ensure that they are available for download.
	First, identify the source from which you installed your packages:
	```{.r filename="Console"}
	# First, install {pak} and {sessioninfo}
	renv::install(c(
	"pak",
	"sessioninfo"
	))
	# Which R packages does the project directly depend on?
	deps <- renv::dependencies()$Package |>
	unique()
	# Which R packages does the project indirectly depend on?
	deps <- deps |>
	pak::pkg_deps(dependencies = NA) |>
	getElement("package")
	# Get information about their source
	sessioninfo::package_info(deps)
	```

Choose a License

code-publishing/choose_license.qmd

Lines 260 to 271 in 1e6b034

	You can learn which license an installed package uses via
	`packageDescription("<PACKAGE_NAME>", fields = "License")`.
	And to identify which licenses are being used by the R packages your project depends on,
	you can use the following code:
	```{.r filename="Console"}
	deps <- renv::dependencies()$Package |>
	unique() |>
	pak::pkg_deps(dependencies = NA) |>
	getElement("package")
	unique(installed.packages(fields="License")[deps, "License"])
	```

Make a README

code-publishing/make_readme.qmd

Lines 86 to 100 in d7837ef

	An overview over the system dependencies of R packages can be created
	using the function `pak::pkg_sysreqs()`.
	In combination with `renv`, we can obtain the system dependencies
	of all R packages the current project directly depends on:
	```{.r filename="Console"}
	# Find all R package dependencies
	deps <- renv::dependencies()$Package |>
	unique() |>
	pak::pkg_deps(dependencies = NA) |>
	getElement("package")
	# Identify their system dependencies
	pak::pkg_sysreqs(deps)
	```

In all three instances, we query the top-level dependencies via renv::dependencies()$Package and then gather the recursive dependencies via pak::pkg_deps(). However, there's a shortcut to the answer because we are using renv: Just look at the lockfile via names(renv::lockfile_read()$Packages).

I should ponder about the pros and cons of directly querying the lockfile.