string.c: fix String#{casecmp,casecmp?} for non-string arguments

* string.c: make String#{casecmp,casecmp?} return nil for
  non-string arguments instead of raising a TypeError.

* test/ruby/test_string.rb: add tests.

Reported by Marcus Stollsteimer.  Based on a patch by Shingo Morita.
[ruby-core:80145] [Bug #13312]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58837 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 14 insertions, 0 deletions

diff --git a/test/ruby/test_string.rb b/test/ruby/test_string.rb
index e1b27fc2be..232d92b2a3 100644
--- a/test/ruby/test_string.rb
+++ b/test/ruby/test_string.rb
@@ -2321,6 +2321,13 @@ CODE
     assert_equal(1, "FoO".casecmp("BaR"))
     assert_equal(-1, "baR".casecmp("FoO"))
     assert_equal(1, "\u3042B".casecmp("\u3042a"))
+
+    assert_nil("foo".casecmp(:foo))
+    assert_nil("foo".casecmp(Object.new))
+
+    o = Object.new
+    def o.to_str; "fOO"; end
+    assert_equal(0, "FoO".casecmp(o))
   end
 
   def test_casecmp?
@@ -2328,6 +2335,13 @@ CODE
     assert_equal(false, 'FoO'.casecmp?('BaR'))
     assert_equal(false, 'baR'.casecmp?('FoO'))
     assert_equal(true, 'äöü'.casecmp?('ÄÖÜ'))
+
+    assert_nil("foo".casecmp?(:foo))
+    assert_nil("foo".casecmp?(Object.new))
+
+    o = Object.new
+    def o.to_str; "fOO"; end
+    assert_equal(true, "FoO".casecmp?(o))
   end
 
   def test_upcase2