Block usage of paste() and paste0() with messaging functions using ...

This linter discourages combining condition functions like stop() with string concatenation functions paste() and paste0(). This is because

• stop(paste0(...)) is redundant as it is exactly equivalent to stop(...)

• stop(paste(...)) is similarly equivalent to stop(...) with separators (see examples)

The same applies to the other default condition functions as well, i.e., warning(), message(), and packageStartupMessage().

Usage

condition_message_linter()

See also

linters for a complete list of linters available in lintr.

Tags

best_practices, consistency

Examples

# will produce lints
lint(
  text = 'stop(paste("a string", "another"))',
  linters = condition_message_linter()
)
#> ::warning file=<text>,line=1,col=1::file=<text>,line=1,col=1,[condition_message_linter] Don't use paste to build stop strings. Instead use the fact that these functions build condition message strings from their input (using "" as a separator). For translatable strings, prefer using gettextf().

lint(
  text = 'warning(paste0("a string", " another"))',
  linters = condition_message_linter()
)
#> ::warning file=<text>,line=1,col=1::file=<text>,line=1,col=1,[condition_message_linter] Don't use paste0 to build warning strings. Instead use the fact that these functions build condition message strings from their input (using "" as a separator). For translatable strings, prefer using gettextf().

# okay
lint(
  text = 'stop("a string", " another")',
  linters = condition_message_linter()
)

lint(
  text = 'warning("a string", " another")',
  linters = condition_message_linter()
)

lint(
  text = 'warning(paste("a string", "another", sep = "-"))',
  linters = condition_message_linter()
)