x509name: return nil for wrong type in Name#<=>

Previously, OpenSSL::X509::Name#{cmp,<=>} would raise a TypeError if you
attempted to compare a Name object with another object of a different
type. Most Ruby classes instead return nil in this situation.

The old behavior resulted in some strange outcomes:

    >> n1 = OpenSSL::X509::Name.new

    >> 'abc' == n1
    => false

    >> n1 == 'abc'
    TypeError: wrong argument type String (expected OpenSSL/X509/NAME)

With the new behavior, cmp/<=> will return nil if the other object is
not an X509::Name instead of raising an error. This allows `==` to also
return false instead of raising an error for type mismatches.

New behavior:

    >> n1 = OpenSSL::X509::Name.new

    >> n1 == 'abc'
    => false

    >> n1 <=> 'abc'
    => nil

1 files changed, 6 insertions, 0 deletions

diff --git a/test/test_x509name.rb b/test/test_x509name.rb
index e31b5e29..531af19f 100644
--- a/test/test_x509name.rb
+++ b/test/test_x509name.rb
@@ -402,6 +402,9 @@ class OpenSSL::TestX509Name < OpenSSL::TestCase
     n2 = OpenSSL::X509::Name.parse_rfc2253 'CN=a'
 
     assert_equal n1, n2
+
+    assert_equal false, n1 == 'abc'
+    assert_equal false, n2 == nil
   end
 
   def test_spaceship
@@ -415,6 +418,9 @@ class OpenSSL::TestX509Name < OpenSSL::TestCase
     assert_equal -1, n2 <=> n3
     assert_equal 1, n3 <=> n1
     assert_equal 1, n3 <=> n2
+    assert_equal nil, n1 <=> 'abc'
+    assert_equal nil, n2 <=> 123
+    assert_equal nil, n3 <=> nil
   end
 
   def name_hash(name)