extconf.rb in plain_apm-0.8.4

- old
+ new
@@ -1,6 +1,84 @@
 require "mkmf"
 
-have_header("ruby/ruby.h") or missing("ruby/ruby.h")
-have_header("ruby/debug.h") or missing("ruby/debug.h")
+def abort_on_missing_ruby_header(name)
+  abort(
+  <<-MSG
+
+      PlainAPM extension needs #{name} Ruby library header to compile.
+
+      If Ruby is installed from a package on your system, please ensure the
+      corresponding Ruby development package is installed as well.
+
+      E.g. on Debian/Ubuntu, this would be achieved by running
+
+      sudo apt install ruby-dev
+
+      on CentOS/Fedora, run
+
+      sudo yum install ruby-devel
+
+      etc...
+  MSG
+  )
+end
+
+def warn_on_ruby_ractor_bugs
+  warn(
+  <<-MSG
+
+     PlainAPM extension to track object allocation on a per-thread basis is
+     built on top of Ruby's TracePoint API.
+
+     However, the currently running Ruby version contains bugs which,
+     when Tracepoints are used in together with Ractors, can cause
+     crashes or inconsistent tracing results.
+
+     Per-thread object allocation tracing will be disabled.
+
+     If you are sure your app is not using Ractors, you can override this by
+     installing plain_apm with --enable-object-tracing-override flag:
+
+     gem install plain_apm -- --enable-object-tracing-override
+
+     When using bundler, you can configure it to pass this flag to the gem
+     install by running:
+
+     bundle config set --global build.plain_apm --enable-object-tracing-override
+
+     See also:
+
+     https://bugs.ruby-lang.org/issues/18464
+     https://bugs.ruby-lang.org/issues/19112
+
+  MSG
+  )
+end
+
+def try_ruby(file)
+  system("ruby", "-W0", File.join(__dir__, file), [:out, :err] => File::NULL)
+end
+
+def enable_object_tracing
+  $defs.push("-DOBJECT_TRACING_ENABLED") unless $defs.include? "-DOBJECT_TRACING_ENABLED"
+end
+
+%w(
+  ruby/ruby.h
+  ruby/debug.h
+).each do |header|
+  have_header(header) or abort_on_missing_ruby_header(header)
+end
+
+if enable_config("object-tracing-override", false)
+  enable_object_tracing
+else
+  bugs = %w(bug18464.rb bug19112).count { |f| !try_ruby(f) }
+
+  if bugs.zero?
+    enable_object_tracing
+  else
+    warn_on_ruby_ractor_bugs
+  end
+end
 
 create_makefile("object_tracing")