[ruby/psych] Implement YAML.safe_dump to make safe_load more usable.

In case where Psych is used as a two way serializers,
e.g. to serialize some cache or config, it is preferable
to have the same restrictions on both load and dump.

Otherwise you might dump and persist some objects payloads
that you later won't be able to read.

https://github.com/ruby/psych/commit/441958396f

1 files changed, 57 insertions, 0 deletions

diff --git a/test/psych/test_psych.rb b/test/psych/test_psych.rb
index 256ed9110c..c9d39c5810 100644
--- a/test/psych/test_psych.rb
+++ b/test/psych/test_psych.rb
@@ -381,4 +381,61 @@ hoge:
     result = Psych.safe_load(yaml, symbolize_names: true)
     assert_equal result, { foo: { bar: "baz", 1 => 2 }, hoge: [{ fuga: "piyo" }] }
   end
+
+  def test_safe_dump_defaults
+    yaml = <<-eoyml
+---
+array:
+- 1
+float: 13.12
+booleans:
+- true
+- false
+eoyml
+
+    payload = YAML.safe_dump({
+      "array" => [1],
+      "float" => 13.12,
+      "booleans" => [true, false],
+    })
+    assert_equal yaml, payload
+  end
+
+  def test_safe_dump_unpermitted_class
+    error = assert_raises Psych::DisallowedClass do
+      YAML.safe_dump(Object.new)
+    end
+    assert_equal "Tried to dump unspecified class: Object", error.message
+
+    hash_subclass = Class.new(Hash)
+    error = assert_raises Psych::DisallowedClass do
+      YAML.safe_dump(hash_subclass.new)
+    end
+    assert_equal "Tried to dump unspecified class: #{hash_subclass.inspect}", error.message
+  end
+
+  def test_safe_dump_extra_permitted_classes
+    assert_equal "--- !ruby/object {}\n", YAML.safe_dump(Object.new, permitted_classes: [Object])
+  end
+
+  def test_safe_dump_symbols
+    error = assert_raises Psych::DisallowedClass do
+      YAML.safe_dump(:foo, permitted_classes: [Symbol])
+    end
+    assert_equal "Tried to dump unspecified class: Symbol(:foo)", error.message
+
+    assert_equal "--- :foo\n", YAML.safe_dump(:foo, permitted_classes: [Symbol], permitted_symbols: [:foo])
+  end
+
+  def test_safe_dump_aliases
+    x = []
+    x << x
+    error = assert_raises Psych::BadAlias do
+      YAML.safe_dump(x)
+    end
+    assert_equal "Tried to dump an aliased object", error.message
+
+    assert_equal "--- &1\n" + "- *1\n", YAML.safe_dump(x, aliases: true)
+  end
+
 end