[strscan] Make strscan Ractor safe (#17)

* Make strscan Ractor safe

* Add test-unit in the development dependencies

ruby/strscan@3c93c2bebe

Author: mrkn

ext/strscan/strscan.c

@@ -1571,6 +1571,10 @@ strscan_fixed_anchor_p(VALUE self)
 void
 Init_strscan(void)
 {
+#ifdef HAVE_RB_EXT_RACTOR_SAFE
+    rb_ext_ractor_safe(true);
+#endif
+
 #undef rb_intern
     ID id_scanerr = rb_intern("ScanError");
     VALUE tmp;

ext/strscan/strscan.gemspec

@@ -17,4 +17,5 @@ Gem::Specification.new do |s|
 
   s.add_development_dependency "rake-compiler"
   s.add_development_dependency "benchmark-driver"
+  s.add_development_dependency "test-unit"
 end

test/strscan/test_ractor.rb

@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+require 'test/unit'
+
+class TestStringScannerRactor < Test::Unit::TestCase
+  def setup
+    skip unless defined? Ractor
+  end
+
+  def test_ractor
+    assert_in_out_err([], <<-"end;", ["stra", " ", "strb", " ", "strc"], [])
+      require "strscan"
+      $VERBOSE = nil
+      r = Ractor.new do
+        s = StringScanner.new("stra strb strc", true)
+        [
+          s.scan(/\\w+/),
+          s.scan(/\\s+/),
+          s.scan(/\\w+/),
+          s.scan(/\\s+/),
+          s.scan(/\\w+/),
+          s.scan(/\\w+/),
+          s.scan(/\\w+/)
+        ]
+      end
+      puts r.take.compact
+    end;
+  end
+end