[ci] [R-package] enforce more {lintr} checks (#6130)

.ci/lint_r_code.R

 
-library(lintr)
+loadNamespace("lintr")
 
 args <- commandArgs(
     trailingOnly = TRUE
@@ -33,30 +33,34 @@ LINTERS_TO_USE <- list(
     , "any_duplicated"       = lintr::any_duplicated_linter()
     , "any_is_na"            = lintr::any_is_na_linter()
     , "assignment"           = lintr::assignment_linter()
+    , "backport"             = lintr::backport_linter()
     , "boolean_arithmetic"   = lintr::boolean_arithmetic_linter()
     , "braces"               = lintr::brace_linter()
     , "class_equals"         = lintr::class_equals_linter()
     , "commas"               = lintr::commas_linter()
+    , "conjunct_test"        = lintr::conjunct_test_linter()
     , "duplicate_argument"   = lintr::duplicate_argument_linter()
     , "empty_assignment"     = lintr::empty_assignment_linter()
     , "equals_na"            = lintr::equals_na_linter()
+    , "fixed_regex"          = lintr::fixed_regex_linter()
     , "for_loop_index"       = lintr::for_loop_index_linter()
     , "function_left"        = lintr::function_left_parentheses_linter()
+    , "function_return"      = lintr::function_return_linter()
+    , "implicit_assignment"  = lintr::implicit_assignment_linter()
     , "implicit_integers"    = lintr::implicit_integer_linter()
     , "infix_spaces"         = lintr::infix_spaces_linter()
     , "inner_combine"        = lintr::inner_combine_linter()
     , "is_numeric"           = lintr::is_numeric_linter()
-    , "fixed_regex"          = lintr::fixed_regex_linter()
-    , "function_return"      = lintr::function_return_linter()
     , "lengths"              = lintr::lengths_linter()
+    , "line_length"          = lintr::line_length_linter(length = 120L)
     , "literal_coercion"     = lintr::literal_coercion_linter()
-    , "long_lines"           = lintr::line_length_linter(length = 120L)
     , "matrix"               = lintr::matrix_apply_linter()
     , "missing_argument"     = lintr::missing_argument_linter()
     , "non_portable_path"    = lintr::nonportable_path_linter()
     , "numeric_leading_zero" = lintr::numeric_leading_zero_linter()
     , "outer_negation"       = lintr::outer_negation_linter()
     , "package_hooks"        = lintr::package_hooks_linter()
+    , "paren_body"           = lintr::paren_body_linter()
     , "paste"                = lintr::paste_linter()
     , "quotes"               = lintr::quotes_linter()
     , "redundant_equals"     = lintr::redundant_equals_linter()
@@ -100,6 +104,7 @@ LINTERS_TO_USE <- list(
             "%>%" = pipe_text
             , "%.%" = pipe_text
             , "%..%" = pipe_text
+            , "|>" = pipe_text
             , "?" = interactive_text
             , "??" = interactive_text
         )
@@ -107,6 +112,7 @@ LINTERS_TO_USE <- list(
     , "unnecessary_concatenation" = lintr::unnecessary_concatenation_linter()
     , "unnecessary_lambda"        = lintr::unnecessary_lambda_linter()
     , "unreachable_code"          = lintr::unreachable_code_linter()
+    , "unused_import"             = lintr::unused_import_linter()
     , "vector_logic"              = lintr::vector_logic_linter()
     , "whitespace"                = lintr::whitespace_linter()
 )

R-package/demo/basic_walkthrough.R

 library(lightgbm)
-library(methods)
 
 # We load in the agaricus dataset
 # In this example, we are aiming to predict whether a mushroom is edible

R-package/demo/boost_from_prediction.R

 library(lightgbm)
-library(methods)
 
 # Load in the agaricus dataset
 data(agaricus.train, package = "lightgbm")

R-package/demo/early_stopping.R

 library(lightgbm)
-library(methods)
 
 # Load in the agaricus dataset
 data(agaricus.train, package = "lightgbm")

R-package/tests/testthat.R

 library(testthat)
-library(lightgbm)
+library(lightgbm)  # nolint: [unused_import]
 
 test_check(
     package = "lightgbm"

R-package/tests/testthat/test_dataset.R

@@ -183,7 +183,9 @@ test_that("lgb.Dataset: colnames", {
     colnames(dtest) <- "asdf"
   })
   new_names <- make.names(seq_len(ncol(test_data)))
-  expect_silent(colnames(dtest) <- new_names)
+  expect_silent({
+    colnames(dtest) <- new_names
+  })
   expect_equal(colnames(dtest), new_names)
 })
 

R-package/tests/testthat/test_learning_to_rank.R

@@ -37,7 +37,8 @@ test_that("learning-to-rank with lgb.train() works as expected", {
     eval_results <- model$eval_train()
     expect_equal(length(eval_results), length(eval_names))
     for (result in eval_results) {
-        expect_true(result[["value"]] > 0.0 && result[["value"]] < 1.0)
+        expect_true(result[["value"]] > 0.0)
+        expect_true(result[["value"]] < 1.0)
         expect_true(result[["higher_better"]])
         expect_identical(result[["data_name"]], "training")
     }
@@ -104,8 +105,10 @@ test_that("learning-to-rank with lgb.cv() works as expected", {
     # check that best score and iter make sense (0.0 < nDCG < 1.0)
     best_iter <- cv_bst$best_iter
     best_score <- cv_bst$best_score
-    expect_true(best_iter > 0L && best_iter <= nrounds)
-    expect_true(best_score > 0.0 && best_score < 1.0)
+    expect_true(best_iter > 0L)
+    expect_true(best_iter <= nrounds)
+    expect_true(best_score > 0.0)
+    expect_true(best_score < 1.0)
     expect_true(abs(best_score - 0.75) < .LGB_NUMERIC_TOLERANCE)
 
     # best_score should be set for the first metric

R-package/tests/testthat/test_lgb.Booster.R

@@ -1275,7 +1275,9 @@ test_that("params (including dataset params) should be stored in .rds file for B
     bst_file <- tempfile(fileext = ".rds")
     expect_warning(saveRDS.lgb.Booster(bst, file = bst_file))
 
-    expect_warning(bst_from_file <- readRDS.lgb.Booster(file = bst_file))
+    expect_warning({
+        bst_from_file <- readRDS.lgb.Booster(file = bst_file)
+    })
     expect_identical(
         bst_from_file$params
         , list(