delete function_brace_linter and merge it into brace_linter

DESCRIPTION

@@ -82,7 +82,6 @@ Collate:
     'expect_type_linter.R'
     'extract.R'
     'extraction_operator_linter.R'
-    'function_brace_linter.R'
     'function_left_parentheses.R'
     'get_source_expressions.R'
     'ids_with_token.R'

NAMESPACE

@@ -49,7 +49,6 @@ export(expect_s4_class_linter)
 export(expect_true_false_linter)
 export(expect_type_linter)
 export(extraction_operator_linter)
-export(function_brace_linter)
 export(function_left_parentheses_linter)
 export(get_source_expressions)
 export(ids_with_token)

NEWS.md

@@ -12,6 +12,7 @@
 * Combined several curly brace related linters into a new `brace_linter` (#1041, @AshesITR):
   + `closed_curly_linter()`
   + Require `else` to come on the same line as the preceding `}`, if present (#884, @michaelchirico)
+  + Require functions spanning multiple lines to use curly braces (@michaelchirico)
 * The `...` arguments for `lint()`, `lint_dir()`, and `lint_package()` have promoted to an earlier position to better match the [Tidyverse design principal](https://design.tidyverse.org/args-data-details.html) of data->descriptor->details. This change enables passing objects to `...` without needing to specify non-required arguments, e.g. `lint_dir("/path/to/dir", linter())` now works without the need to specify `relative_path`. This affects some code that uses positional arguments. (#935, @michaelchirico)
   + For `lint()`, `...` is now the 3rd argument, where earlier this was `cache=`
   + For `lint_dir()` and `lint_package()`, `...` is now the 2nd argument, where earlier this was `relative_path=`

R/brace_linter.R

@@ -4,11 +4,13 @@
 #'
 #'  - Curly braces are on their own line unless they are followed by an `else`.
 #'  - Closing curly braces in `if` conditions are on the same line as the corresponding `else`.
+#'  - Functions spanning multiple lines use curly braces.
 #'
 #' @param allow_single_line if `TRUE`, allow an open and closed curly pair on the same line.
 #'
 #' @evalRd rd_tags("brace_linter")
-#' @seealso [linters] for a complete list of linters available in lintr.
+#' @seealso [linters] for a complete list of linters available in lintr. \cr
+#'   <https://style.tidyverse.org/syntax.html#indenting>
 #' @export
 brace_linter <- function(allow_single_line = FALSE) {
   Linter(function(source_expression) {
@@ -63,6 +65,15 @@ brace_linter <- function(allow_single_line = FALSE) {
       lint_message = "`else` should come on the same line as the previous `}`."
     ))
 
+    xp_function_brace <- "//expr[FUNCTION and @line1 != @line2 and not(expr[OP-LEFT-BRACE])]"
+
+    lints <- c(lints, lapply(
+      xml2::xml_find_all(source_expression$xml_parsed_content, xp_function_brace),
+      xml_nodes_to_lint,
+      source_file = source_expression,
+      lint_message = "Any function spanning multiple lines should use curly braces."
+    ))
+
     lints
   })
 }

R/zzz.R

@@ -18,7 +18,6 @@ default_linters <- with_defaults(
   commented_code_linter(),
   cyclocomp_linter(),
   equals_na_linter(),
-  function_brace_linter(),
   function_left_parentheses_linter(),
   if_else_match_braces_linter(),
   infix_spaces_linter(),

inst/lintr/linters.csv

@@ -26,7 +26,6 @@ expect_s4_class_linter,package_development best_practices
 expect_true_false_linter,package_development best_practices readability
 expect_type_linter,package_development best_practices
 extraction_operator_linter,style best_practices
-function_brace_linter,default style readability
 function_left_parentheses_linter,style readability default
 if_else_match_braces_linter,default style readability
 ifelse_censor_linter,best_practices efficiency

tests/testthat/test-brace_linter.R

@@ -123,3 +123,24 @@ test_that("brace_linter lints else correctly", {
   )
 })
 
+test_that("brace_linter lints function expressions correctly", {
+  linter <- brace_linter()
+  expect_lint("function(x) 4", NULL, linter)
+
+  lines <- trim_some("
+    function(x) {
+      x + 4
+    }
+  ")
+  expect_lint(lines, NULL, linter)
+
+  lines <- trim_some("
+    function(x)
+      x+4
+  ")
+  expect_lint(
+    lines,
+    rex::rex("Any function spanning multiple lines should use curly braces."),
+    linter
+  )
+})