Handle unused variable with `glue`

[denrou]

The following code gives a warning when lint is applied:

library(glue)
test <- function() {
  x <- 1
  glue("{x}")
}

The warning is local variable 'x' assigned but may not be used.

It appears the linter object_usage_linter refers to codetools::checkUsage, which is not available on github unfortunately (so I can't open an issue). I was wondering if this issue could be handle by lintr directly or if a workaround exists.

For now, I applied a #nolint (unused variable) for each problematic line.

[russHyde]

Reprex:

expect_lint(
  "library(glue)\ntest <- function() {\n  x <- 1\nglue::glue('{x}')\n}\n",
  NULL,
  object_usage_linter)

[russHyde]

Similar to the object_usage_linter issue in #358

[jimhester]

The object usage linter now respects variables declared in utils::globalVariables(), so you can add them there to avoid these warnings.

[dragosmg]

I'm not quite sure why, but declaring global variables with utils doesn't seem to work for me. object_usage_linter() still complains when i define a variable and the use it only with glue::glue.

I think the way the check has been implemented in object_usage_linter() reads the global variables (declared_globals) after the package has been installed, while I usually run lintr::lint_package() before installing the new version. Is this the desired behaviour or am I missing anything?

Maybe useful to mention I am using the latest dev version of lintr (2.0.0.9000).

[jimhester]

You need to install the package before linting it.