skip c() unless >1 argument is used

r-lib · Jul 25, 2023 · a5170bf · a5170bf
1 parent 25d24c0
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diff --git a/NEWS.md b/NEWS.md
@@ -1,5 +1,9 @@
 # lintr (development version)
 
+## Bug fixes
+
+* `inner_combine_linter()` no longer throws on length-1 calls to `c()` like `c(exp(2))` or `c(log(3))` (#2017, @MichaelChirico). Such usage is discouraged by `unnecessary_concatenation_linter()`, but `inner_combine_linter()` _per se_ does not apply.
+
 # lintr 3.1.0
 
 ## Deprecations & Breaking Changes

diff --git a/R/inner_combine_linter.R b/R/inner_combine_linter.R
@@ -78,7 +78,7 @@ inner_combine_linter <- function() {
   )
   xpath <- glue::glue("
   //SYMBOL_FUNCTION_CALL[text() = 'c']
-    /parent::expr
+    /parent::expr[count(following-sibling::expr) > 1]
     /following-sibling::expr[1][ {c_expr_cond} ]
     /parent::expr
   ")

diff --git a/tests/testthat/test-inner_combine_linter.R b/tests/testthat/test-inner_combine_linter.R
@@ -67,6 +67,10 @@ test_that("inner_combine_linter is order-agnostic for matching arguments", {
   )
 })
 
+test_that("c() with ...length()=1 is OK", {
+  expect_lint("c(exp())", NULL, inner_combine_linter())
+})
+
 skip_if_not_installed("tibble")
 patrick::with_parameters_test_that(
   "inner_combine_linter skips allowed usages:",