fix paste(collapse='') lints inside pipes (#2572)

* fix paste(collapse='') lints inside pipes

* pipes() is the test helper, not namespace object

* longer line

* parameterize test

Author: MichaelChirico

R/paste_linter.R

@@ -167,14 +167,15 @@ paste_linter <- function(allow_empty_sep = FALSE,
   empty_paste_note <-
     'Note that paste() converts empty inputs to "", whereas file.path() leaves it empty.'
 
-  paste0_collapse_xpath <- "
+  paste0_collapse_xpath <- glue::glue("
   parent::expr
     /parent::expr[
       SYMBOL_SUB[text() = 'collapse']
-      and count(expr) = 3
+      and count(expr) =
+        3 - count(preceding-sibling::*[self::PIPE or self::SPECIAL[{ xp_text_in_table(magrittr_pipes) }]])
       and not(expr/SYMBOL[text() = '...'])
     ]
-  "
+  ")
 
   Linter(linter_level = "expression", function(source_expression) {
     paste_calls <- source_expression$xml_find_function_calls("paste")

tests/testthat/test-paste_linter.R

@@ -249,6 +249,22 @@ test_that("paste0(collapse=...) is caught", {
   expect_lint("paste0(foo(x, y, z), collapse = '')", lint_msg, linter)
 })
 
+local({
+  linter <- paste_linter()
+  lint_msg <- rex::rex("Use paste(), not paste0(), to collapse a character vector when sep= is not used.")
+  pipes <- pipes()
+
+  patrick::with_parameters_test_that(
+    "paste0(collapse=...) is caught in pipes",
+    {
+      expect_lint(sprintf('x %s paste0(y, collapse = "")', pipe), NULL, linter)
+      expect_lint(sprintf('x %s paste0(collapse = "")', pipe), lint_msg, linter)
+    },
+    pipe = pipes,
+    .test_name = pipes
+  )
+})
+
 test_that("paste0(collapse=...) cases interacting with other rules are handled", {
   linter <- paste_linter()
   lint_msg <- rex::rex("Use paste(), not paste0(), to collapse a character vector when sep= is not used.")