Changelog • arg

arg (development version)

Added arg_color() (and variants) to check whether an argument corresponds to a valid color specification.
Fixed a bug where the message provided to .msg (if any) was not evaluated in the correct environment.
arg_counts() and arg_whole_numeric() (and their scalar equivalents) now check whether a value is a whole number using rlang::is_integerish() instead of the criterion used by all.equal().

CRAN release: 2026-05-27

err(), wrn(), and msg() now pass arguments specified in ... to rlang::abort(), rlang::warn(), and rlang::inform(), respectively.
When an error is caused by a failure to process a given fixed argument (e.g., bounds in arg_gt() or len in arg_length()), that error is now thrown correctly in arg_or(), arg_and(), when_supplied(), and when_not_null(). Previously, it was bundled with the errors thrown to the ultimate user of the function and_or(), etc., was used in, which it made it confusing to diagnose.
Fixed bugs with arg_or(), arg_and(), when_supplied(), and when_not_null().
Fixed a bug where an extra period might be added after an error message.
When the empty string ("") is supplied to err(), etc., it is no longer appended with a period.
Improved error messages for arg_element() and arg_not_element().
The .msg argument of arg_*() functions is now checked to ensure it is a string when not NULL.

CRAN release: 2026-04-09