Fix ruby segment fault (#3708)

* Fix ruby segment fault

1) rb_ary_new cannot be called during allocate function. During allocate
fucntion, the containing object hasn't been marked and rb_ary_new may
invoke gc to collect containing object.
2) The global map should be marked before allocating it. Otherwise it
may be garbage collected.

* Add test

* Remove commented code

* Fix grammer error

1 files changed, 58 insertions, 0 deletions

diff --git a/ruby/tests/gc_test.rb b/ruby/tests/gc_test.rb
new file mode 100644
index 00000000..f3470cca
--- /dev/null
+++ b/ruby/tests/gc_test.rb
@@ -0,0 +1,58 @@
+#!/usr/bin/ruby
+#
+# generated_code.rb is in the same directory as this test.
+$LOAD_PATH.unshift(File.expand_path(File.dirname(__FILE__)))
+
+old_gc = GC.stress
+GC.stress = 0x01 | 0x04
+require 'generated_code_pb'
+GC.stress = old_gc
+
+require 'test/unit'
+
+class GCTest < Test::Unit::TestCase
+  def get_msg
+    A::B::C::TestMessage.new(
+        :optional_int32 => 1,
+        :optional_int64 => 1,
+        :optional_uint32 => 1,
+        :optional_uint64 => 1,
+        :optional_bool => true,
+        :optional_double => 1.0,
+        :optional_float => 1.0,
+        :optional_string => "a",
+        :optional_bytes => "b",
+        :optional_enum => A::B::C::TestEnum::A,
+        :optional_msg => A::B::C::TestMessage.new(),
+        :repeated_int32 => [1],
+        :repeated_int64 => [1],
+        :repeated_uint32 => [1],
+        :repeated_uint64 => [1],
+        :repeated_bool => [true],
+        :repeated_double => [1.0],
+        :repeated_float => [1.0],
+        :repeated_string => ["a"],
+        :repeated_bytes => ["b"],
+        :repeated_enum => [A::B::C::TestEnum::A],
+        :repeated_msg => [A::B::C::TestMessage.new()],
+        :map_int32_string => {1 => "a"},
+        :map_int64_string => {1 => "a"},
+        :map_uint32_string => {1 => "a"},
+        :map_uint64_string => {1 => "a"},
+        :map_bool_string => {true => "a"},
+        :map_string_string => {"a" => "a"},
+        :map_string_msg => {"a" => A::B::C::TestMessage.new()},
+        :map_string_int32 => {"a" => 1},
+        :map_string_bool => {"a" => true},
+    )
+  end
+  def test_generated_msg
+    old_gc = GC.stress
+    GC.stress = 0x01 | 0x04
+    from = get_msg
+    data = A::B::C::TestMessage.encode(from)
+    to = A::B::C::TestMessage.decode(data)
+    GC.stress = old_gc
+    puts "passed"
+  end
+end