From 0c36ba53192c5a0d245c9b626e4346a32d7d144e Mon Sep 17 00:00:00 2001
From: Mike Dalessio <mike.dalessio@gmail.com>
Date: Mon, 23 May 2022 17:31:14 -0400
Subject: Define unsupported GC compaction methods as rb_f_notimplement

Fixes [Bug #18779]

Define the following methods as `rb_f_notimplement` on unsupported
platforms:

- GC.compact
- GC.auto_compact
- GC.auto_compact=
- GC.latest_compact_info
- GC.verify_compaction_references

This change allows users to call `GC.respond_to?(:compact)` to
properly test for compaction support. Previously, it was necessary to
invoke `GC.compact` or `GC.verify_compaction_references` and check if
those methods raised `NotImplementedError` to determine if compaction
was supported.

This follows the precedent set for other platform-specific
methods. For example, in `process.c` for methods such as
`Process.fork`, `Process.setpgid`, and `Process.getpriority`.
---
 test/ruby/test_gc_compact.rb | 58 ++++++++++++++++++++++++++++++++------------
 1 file changed, 43 insertions(+), 15 deletions(-)

(limited to 'test/ruby/test_gc_compact.rb')

diff --git a/test/ruby/test_gc_compact.rb b/test/ruby/test_gc_compact.rb
index 16b15b39ac..da0023e6f3 100644
--- a/test/ruby/test_gc_compact.rb
+++ b/test/ruby/test_gc_compact.rb
@@ -9,14 +9,7 @@ if RUBY_PLATFORM =~ /s390x/
 end
 
 class TestGCCompact < Test::Unit::TestCase
-  module SupportsCompact
-    def setup
-      omit "autocompact not supported on this platform" unless supports_auto_compact?
-      super
-    end
-
-    private
-
+  module CompactionSupportInspector
     def supports_auto_compact?
       return false if /wasm/ =~ RUBY_PLATFORM
       return true unless defined?(Etc::SC_PAGE_SIZE)
@@ -31,10 +24,19 @@ class TestGCCompact < Test::Unit::TestCase
     end
   end
 
-  include SupportsCompact
+  module OmitUnlessCompactSupported
+    include CompactionSupportInspector
+
+    def setup
+      omit "autocompact not supported on this platform" unless supports_auto_compact?
+      super
+    end
+  end
+
+  include OmitUnlessCompactSupported
 
   class AutoCompact < Test::Unit::TestCase
-    include SupportsCompact
+    include OmitUnlessCompactSupported
 
     def test_enable_autocompact
       before = GC.auto_compact
@@ -88,13 +90,39 @@ class TestGCCompact < Test::Unit::TestCase
     end
   end
 
-  def os_page_size
-    return true unless defined?(Etc::SC_PAGE_SIZE)
+  class CompactMethodsNotImplemented < Test::Unit::TestCase
+    include CompactionSupportInspector
+
+    def assert_not_implemented(method, *args)
+      omit "autocompact is supported on this platform" if supports_auto_compact?
+
+      assert_raise(NotImplementedError) { GC.send(method, *args) }
+      refute(GC.respond_to?(method), "GC.#{method} should be defined as rb_f_notimplement")
+    end
+
+    def test_gc_compact_not_implemented
+      assert_not_implemented(:compact)
+    end
+
+    def test_gc_auto_compact_get_not_implemented
+      assert_not_implemented(:auto_compact)
+    end
+
+    def test_gc_auto_compact_set_not_implemented
+      assert_not_implemented(:auto_compact=, true)
+    end
+
+    def test_gc_latest_compact_info_not_implemented
+      assert_not_implemented(:latest_compact_info)
+    end
+
+    def test_gc_verify_compaction_references_not_implemented
+      assert_not_implemented(:verify_compaction_references)
+    end
   end
 
-  def setup
-    omit "autocompact not supported on this platform" unless supports_auto_compact?
-    super
+  def os_page_size
+    return true unless defined?(Etc::SC_PAGE_SIZE)
   end
 
   def test_gc_compact_stats
-- 
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