test: try using ruby_memcheck to look for leaks

.github/workflows/ci.yml

@@ -296,3 +296,26 @@ jobs:
             bundle install --local || bundle install
             bundle exec rake compile -- --${{matrix.sys}}-system-libraries
             bundle exec rake test
+
+  memcheck:
+    continue-on-error: true # this is experimental!
+    strategy:
+      fail-fast: false
+      matrix:
+        sys: ["enable", "disable"]
+        ruby: ["3.0"]
+    runs-on: ubuntu-latest
+    container:
+      image: ghcr.io/sparklemotion/nokogiri-test:mri-${{matrix.ruby}}
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          submodules: true
+      - uses: actions/cache@v2
+        if: matrix.sys == 'disable'
+        with:
+          path: ports
+          key: ports-ubuntu-${{hashFiles('dependencies.yml', 'patches/**/*.patch')}}
+      - run: bundle install --local || bundle install
+      - run: bundle exec rake compile -- --${{matrix.sys}}-system-libraries
+      - run: bundle exec rake test:memcheck

nokogiri.gemspec

@@ -333,6 +333,7 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency("rubocop-performance", "~> 1.11")
   spec.add_development_dependency("rubocop-rake", "~> 0.6")
   spec.add_development_dependency("rubocop-shopify", "~> 2.3")
+  spec.add_development_dependency("ruby_memcheck", "~> 1.0")
   spec.add_development_dependency("simplecov", "~> 0.20")
 
   spec.extensions << "ext/nokogiri/extconf.rb"

rakelib/test.rake

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require "rake/testtask"
+require "ruby_memcheck"
 
 #
 #  much of this was ripped out of hoe-debugging
@@ -15,6 +16,11 @@ class ValgrindTestTask < Rake::TestTask
                       "--error-exitcode=#{ERROR_EXITCODE}",
                       "--gen-suppressions=all",]
 
+  RubyMemcheck.config(
+    binary_name: "nokogiri",
+    valgrind_generate_suppressions: true,
+  )
+
   def ruby(*args, **options, &block)
     valgrind_options = check_for_suppression_file(VALGRIND_OPTIONS)
     command = "ulimit -s unlimited && valgrind #{valgrind_options.join(" ")} #{RUBY} #{args.join(" ")}"
@@ -96,4 +102,8 @@ namespace "test" do
   LldbTestTask.new("lldb") do |t|
     nokogiri_test_task_configuration(t)
   end
+
+  RubyMemcheck::TestTask.new("memcheck") do |t|
+    nokogiri_test_task_configuration(t)
+  end
 end

test/helper.rb

@@ -12,6 +12,10 @@
 #   - "stress" - run tests with GC.stress set to true
 # - NOKOGIRI_GC: read more in test/test_memory_leak.rb
 #
+
+# make sure we do one final major before the process exits (for valgrind)
+at_exit { GC.start(full_mark: true) } unless ::RUBY_PLATFORM == "java"
+
 require "simplecov"
 SimpleCov.start do
   add_filter "/test/"