Merge pull request #9390 from ruby/keep-lib-ext-and-warn

Revert `DEFAULT_INSTALL_EXTENSION_IN_LIB` and warn `require_relative` with C ext

Author: hsbt

lib/rubygems/config_file.rb

@@ -47,7 +47,7 @@ class Gem::ConfigFile
   DEFAULT_CONCURRENT_DOWNLOADS = 8
   DEFAULT_CERT_EXPIRATION_LENGTH_DAYS = 365
   DEFAULT_IPV4_FALLBACK_ENABLED = false
-  DEFAULT_INSTALL_EXTENSION_IN_LIB = false
+  DEFAULT_INSTALL_EXTENSION_IN_LIB = true
   DEFAULT_GLOBAL_GEM_CACHE = false
   DEFAULT_USE_PSYCH = false
 

lib/rubygems/specification_policy.rb

@@ -476,6 +476,7 @@ def validate_extensions # :nodoc:
 
     validate_rake_extensions(builder)
     validate_rust_extensions(builder)
+    validate_extension_require_relative
   end
 
   def validate_rust_extensions(builder) # :nodoc:
@@ -496,6 +497,33 @@ def validate_rake_extensions(builder) # :nodoc:
     WARNING
   end
 
+  def validate_extension_require_relative # :nodoc:
+    return unless @specification.extensions.any?
+
+    require_paths = @specification.require_paths
+
+    @specification.files.each do |rb_file|
+      next unless rb_file.end_with?(".rb")
+      next unless require_paths.any? {|rp| rb_file.start_with?("#{rp}/") }
+      next unless File.file?(rb_file)
+
+      File.foreach(rb_file).with_index(1) do |line, lineno|
+        next unless line =~ /^\s*require_relative\s+["']([^"']+)["']/
+
+        required_path = Regexp.last_match(1)
+        resolved = File.join(File.dirname(rb_file), required_path)
+
+        next if @specification.files.any? {|f| f == "#{resolved}.rb" || f == resolved }
+
+        warning <<~WARNING
+          #{rb_file}:#{lineno} uses `require_relative "#{required_path}"` to load a compiled extension.
+          This will break in RubyGems 4.2, which will stop copying compiled extensions into the gem's lib directory.
+          Use `require` instead of `require_relative` to load compiled extensions.
+        WARNING
+      end
+    end
+  end
+
   def validate_unique_links
     links = @specification.metadata.slice(*METADATA_LINK_KEYS)
     grouped = links.group_by {|_key, uri| uri }

test/rubygems/test_gem_config_file.rb

@@ -43,7 +43,7 @@ def test_initialize
     assert_equal [@gem_repo], Gem.sources
     assert_equal 365, @cfg.cert_expiration_length_days
     assert_equal false, @cfg.ipv4_fallback_enabled
-    assert_equal false, @cfg.install_extension_in_lib
+    assert_equal true, @cfg.install_extension_in_lib
 
     File.open @temp_conf, "w" do |fp|
       fp.puts ":backtrace: true"
@@ -59,7 +59,7 @@ def test_initialize
       fp.puts ":ssl_verify_mode: 0"
       fp.puts ":ssl_ca_cert: /etc/ssl/certs"
       fp.puts ":cert_expiration_length_days: 28"
-      fp.puts ":install_extension_in_lib: true"
+      fp.puts ":install_extension_in_lib: false"
       fp.puts ":ipv4_fallback_enabled: true"
     end
 
@@ -75,7 +75,7 @@ def test_initialize
     assert_equal 0, @cfg.ssl_verify_mode
     assert_equal "/etc/ssl/certs", @cfg.ssl_ca_cert
     assert_equal 28, @cfg.cert_expiration_length_days
-    assert_equal true, @cfg.install_extension_in_lib
+    assert_equal false, @cfg.install_extension_in_lib
     assert_equal true, @cfg.ipv4_fallback_enabled
   end
 

test/rubygems/test_gem_specification.rb

@@ -2887,6 +2887,61 @@ def test_validate_rust_extension_have_no_missing_cargo_toml_error
     end
   end
 
+  def test_validate_extension_require_relative_warning
+    util_setup_validate
+
+    Dir.chdir @tempdir do
+      @a1.extensions = ["ext/a/extconf.rb"]
+      @a1.files = %w[lib/code.rb lib/a.rb ext/a/extconf.rb]
+
+      File.write File.join("lib", "a.rb"), 'require_relative "a/a"'
+
+      use_ui @ui do
+        @a1.validate
+      end
+
+      assert_match(%r{require_relative "a/a"}, @ui.error)
+      assert_match(/will break in RubyGems 4\.2/, @ui.error)
+      assert_match(/Use `require` instead of `require_relative`/, @ui.error)
+    end
+  end
+
+  def test_validate_extension_require_relative_no_warning_when_rb_exists
+    util_setup_validate
+
+    Dir.chdir @tempdir do
+      @a1.extensions = ["ext/a/extconf.rb"]
+      @a1.files = %w[lib/code.rb lib/a.rb lib/a/a.rb ext/a/extconf.rb]
+
+      FileUtils.mkdir_p File.join("lib", "a")
+      File.write File.join("lib", "a.rb"), 'require_relative "a/a"'
+      File.write File.join("lib", "a", "a.rb"), ""
+
+      use_ui @ui do
+        @a1.validate
+      end
+
+      refute_match(/require_relative/, @ui.error)
+    end
+  end
+
+  def test_validate_extension_require_relative_no_warning_without_extensions
+    util_setup_validate
+
+    Dir.chdir @tempdir do
+      @a1.extensions = []
+      @a1.files = %w[lib/code.rb lib/a.rb]
+
+      File.write File.join("lib", "a.rb"), 'require_relative "a/a"'
+
+      use_ui @ui do
+        @a1.validate
+      end
+
+      refute_match(/require_relative/, @ui.error)
+    end
+  end
+
   def test_validate_description
     util_setup_validate