Fix a false positive for Lint/IncompatibleIoSelectWithFiberScheduler

This PR fixes a false positive for `Lint/IncompatibleIoSelectWithFiberScheduler`
when using excepts argument.

AFAIK, `IO.wait_readable` and `IO.wait_writable` cannot replace IO objects waiting for exceptions.

changelog/fix_a_false_positive_for_lint_incompatible_io_select_with_fiber_scheduler.md

@@ -0,0 +1 @@
+* [#11830](https://github.com/rubocop/rubocop/pull/11830): Fix a false positive for `Lint/IncompatibleIoSelectWithFiberScheduler`. ([@koic][])

lib/rubocop/cop/lint/incompatible_io_select_with_fiber_scheduler.rb

@@ -6,6 +6,9 @@ module Lint
       #
       # This cop checks for `IO.select` that is incompatible with Fiber Scheduler since Ruby 3.0.
       #
+      # When an array of IO objects waiting for an exception (the third argument of `IO.select`)
+      # is used as an argument, there is no alternative API, so offenses are not registered.
+      #
       # NOTE: When the method is successful the return value of `IO.select` is `[[IO]]`,
       # and the return value of `io.wait_readable` and `io.wait_writable` are `self`.
       # They are not autocorrected when assigning a return value because these types are different.
@@ -42,8 +45,8 @@ class IncompatibleIoSelectWithFiberScheduler < Base
         PATTERN
 
         def on_send(node)
-          read, write, _excepts, timeout = *io_select(node)
-          return unless read
+          read, write, excepts, timeout = *io_select(node)
+          return if excepts && !excepts.children.empty?
           return unless scheduler_compatible?(read, write) || scheduler_compatible?(write, read)
 
           preferred = preferred_method(read, write, timeout)

spec/rubocop/cop/lint/incompatible_io_select_with_fiber_scheduler_spec.rb

@@ -164,6 +164,12 @@
     RUBY
   end
 
+  it 'does not register an offense when using `IO.select` with read and excepts arguments' do
+    expect_no_offenses(<<~RUBY)
+      IO.select([rp], [], [excepts])
+    RUBY
+  end
+
   it 'does not register an offense when using `Enumerable#select`' do
     expect_no_offenses(<<~RUBY)
       collection.select { |item| item.do_something? }