From f505cee07afe05eafadb95baadc74bece7cb5089 Mon Sep 17 00:00:00 2001
From: Earlopain <14981592+Earlopain@users.noreply.github.com>
Date: Mon, 27 May 2024 22:55:04 +0200
Subject: [PATCH] [Fix #12910] Ensure that RuboCop runs warning-free

This is inspired by how Rails approaches this
---
 spec/spec_helper.rb             |  3 +++
 spec/support/strict_warnings.rb | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+)
 create mode 100644 spec/support/strict_warnings.rb

diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index d65c777089a2..f643ca4fe93b 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -4,6 +4,9 @@
 require 'rainbow'
 Rainbow.enabled = false
 
+require_relative 'support/strict_warnings'
+StrictWarnings.enable!
+
 require 'rubocop'
 require 'rubocop/cop/internal_affairs'
 require 'rubocop/server'
diff --git a/spec/support/strict_warnings.rb b/spec/support/strict_warnings.rb
new file mode 100644
index 000000000000..86dc87913d9b
--- /dev/null
+++ b/spec/support/strict_warnings.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+module StrictWarnings
+  class WarningError < StandardError; end
+
+  # Warnings from 3rd-party gems
+  SUPPRESSED_WARNINGS = Regexp.union(
+    %r{lib/parser/builders/default.*Unknown escape},
+    %r{lib/parser/builders/default.*character class has duplicated range},
+    /internal.*Float.*out of range/ # also from the parser gem
+  )
+
+  def warn(message, ...)
+    return if SUPPRESSED_WARNINGS.match?(message)
+
+    super
+    # RuboCop uses `warn` to display some of its output and tests assert against
+    # that. Assume that warnings are intentional when stderr is redirected.
+    return if $stderr.is_a?(StringIO)
+    # Ignore warnings from dev/rc ruby versions. Things are subject to change and
+    # contributors should not be bothered by them with red CI.
+    return if RUBY_PATCHLEVEL == -1
+
+    raise WarningError
+  end
+
+  def self.enable!
+    $VERBOSE = true
+    Warning[:deprecated] = true
+    Warning.singleton_class.prepend(self)
+  end
+end