Customizing sessioncheck() behavior

This article discusses how to customize the checks that are performed when sessioncheck() is called. The easiest way to alter its behavior is via the action argument, which specifies what action should be taken if an issue is detected (allowed values: "warn", "error", "message", "none"), and via the checks argument, which specifies which checks should be performed. The default behavior corresponds to this:

sessioncheck::sessioncheck(
  action = "warn",
  checks = c(
    "globalenv_objects", 
    "attached_packages", 
    "attached_environments"
  )
)

In this case, three checks are performed:

• "globalenv_objects" indicates that check_globalenv_objects() should be used
• "attached_packages" indicates that check_attached_packages() should be used
• "attached_environments" indicates that check_attached_environments() should be used

Several other options can be specified:

• "loaded_namespaces" indicates that check_loaded_namespaces() should be used
• "sessiontime" indicates that check_sessiontime() should be used
• "working_directory" indicates that check_working_directory() should be used
• "required_options" indicates that check_required_options() should be used
• "required_locale" indicates that check_required_locale() should be used
• "required_sysenv" indicates that check_required_sysenv() should be used

For example, this checks the loaded namespaces only:

sessioncheck::sessioncheck(
  action = "warn",
  checks = "loaded_namespaces"
)
#> Warning: Session check results:
#> ✖ Unexpected namespaces: digest, desc, R6, fastmap, and 20 more

The individual checks can themselves be customized. Each check function has one extra argument that is used to control its behavior, and these can be passed to the check function via .... For example, you can do this:

sessioncheck::sessioncheck(
  action = "warn",
  checks = c("loaded_namespaces", "required_options"),
  allow_loaded_namespaces = c("knitr", "vctrs", "cli"),
  required_options = list(scipen = 0L, max.print = 50L)
)
#> Warning: Session check results:
#> ✖ Unexpected namespaces: digest, desc, R6, fastmap, and 18 more
#> ✖ Unexpected options:
#>     max.print: expected 50, got 99999

The relevant arguments that can be passed via ... are as follows:

• allow_globalenv_objects is passed to check_globalenv_objects()
• allow_attached_packages is passed to check_attached_packages()
• allow_attached_environments is passed to check_attached_environments()
• allow_loaded_namespaces is passed to check_loaded_namespaces()
• max_sessiontime is passed to check_sessiontime()
• required_wd is passed to check_working_directory()
• required_options is passed to check_required_options()
• required_locale is passed to check_required_locale()
• required_sysenv is passed to check_required_sysenv()

To make life a little easier, the default values for all arguments can be specified via options(). For example, you could include something like this in the .Rprofile:

options(
  sessioncheck = list(
    action = "message",
    checks = c("loaded_namespaces", "required_options"),
    allow_loaded_namespaces = c("knitr", "vctrs", "cli"),
    required_options = list(scipen = 0L, max.print = 50L)
  )
)

When called, sessioncheck() will now use these values:

sessioncheck::sessioncheck()
#> Session check results:
#> ✖ Unexpected namespaces: digest, desc, R6, fastmap, and 18 more
#> ✖ Unexpected options:
#>     max.print: expected 50, got 99999

For more information on the specifics of each check, please see the documentation of the relevant check function or the article on individual checks.