Support old versions of Ruby with FrozenError.

They should work separatedly from Ruby core repository.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64215 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/ostruct.rb

@@ -156,7 +156,8 @@ class OpenStruct
     begin
       @modifiable = true
     rescue
-      raise FrozenError, "can't modify frozen #{self.class}", caller(3)
+      exception_class = defined?(FrozenError) ? FrozenError : RuntimeError
+      raise exception_class, "can't modify frozen #{self.class}", caller(3)
     end
     @table
   end

test/date/test_date_marshal.rb

@@ -30,13 +30,15 @@ class TestDateMarshal < Test::Unit::TestCase
     a = d.marshal_dump
     d.freeze
     assert(d.frozen?)
-    assert_raise(FrozenError){d.marshal_load(a)}
+    expected_error = defined?(FrozenError) ? FrozenError : RuntimeError
+    assert_raise(expected_error){d.marshal_load(a)}
 
     d = DateTime.now
     a = d.marshal_dump
     d.freeze
     assert(d.frozen?)
-    assert_raise(FrozenError){d.marshal_load(a)}
+    expected_error = defined?(FrozenError) ? FrozenError : RuntimeError
+    assert_raise(expected_error){d.marshal_load(a)}
   end
 
 end

test/dbm/test_dbm.rb

@@ -625,9 +625,10 @@ if defined? DBM
     end
 
     def test_freeze
+      expected_error = defined?(FrozenError) ? FrozenError : RuntimeError
       DBM.open("#{@tmproot}/a") {|d|
         d.freeze
-        assert_raise(FrozenError) { d["k"] = "v" }
+        assert_raise(expected_error) { d["k"] = "v" }
       }
     end
   end

test/gdbm/test_gdbm.rb

@@ -726,7 +726,8 @@ if defined? GDBM
     def test_freeze
       GDBM.open("#{@tmproot}/a.dbm") {|d|
         d.freeze
-        assert_raise(FrozenError) { d["k"] = "v" }
+        expected_error = defined?(FrozenError) ? FrozenError : RuntimeError
+        assert_raise(expected_error) { d["k"] = "v" }
       }
     end
   end

test/ostruct/test_ostruct.rb

@@ -66,15 +66,16 @@ class TC_OpenStruct < Test::Unit::TestCase
     o = OpenStruct.new(foo: 42)
     o.a = 'a'
     o.freeze
-    assert_raise(FrozenError) {o.b = 'b'}
+    expected_error = defined?(FrozenError) ? FrozenError : RuntimeError
+    assert_raise(expected_error) {o.b = 'b'}
     assert_not_respond_to(o, :b)
-    assert_raise(FrozenError) {o.a = 'z'}
+    assert_raise(expected_error) {o.a = 'z'}
     assert_equal('a', o.a)
     assert_equal(42, o.foo)
     o = OpenStruct.new :a => 42
     def o.frozen?; nil end
     o.freeze
-    assert_raise(FrozenError, '[ruby-core:22559]') {o.a = 1764}
+    assert_raise(expected_error, '[ruby-core:22559]') {o.a = 1764}
   end
 
   def test_delete_field

test/stringio/test_stringio.rb

@@ -722,9 +722,10 @@ class TestStringIO < Test::Unit::TestCase
     s = StringIO.new
     s.freeze
     bug = '[ruby-core:33648]'
-    assert_raise(FrozenError, bug) {s.puts("foo")}
-    assert_raise(FrozenError, bug) {s.string = "foo"}
-    assert_raise(FrozenError, bug) {s.reopen("")}
+    exception_class = defined?(FrozenError) ? FrozenError : RuntimeError
+    assert_raise(exception_class, bug) {s.puts("foo")}
+    assert_raise(exception_class, bug) {s.string = "foo"}
+    assert_raise(exception_class, bug) {s.reopen("")}
   end
 
   def test_frozen_string