* numeric.c (do_coerce): Add a warning when an exception is raised

  or an invalid value is returned in #coerce called by
  numeric comparison operators and the exception
  thrown by the caller has no information on the failure.
  In the next release such exception should not be rescued or
  should be the cause of the caller exception. nil is accepted
  as the "no possible coercion" return value. See #7688.
* test/ruby/test_numeric.rb: Add corresponding test.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46375 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 17 insertions, 0 deletions

diff --git a/test/ruby/test_numeric.rb b/test/ruby/test_numeric.rb
index 674e869473..b42509dd1a 100644
--- a/test/ruby/test_numeric.rb
+++ b/test/ruby/test_numeric.rb
@@ -59,6 +59,23 @@ class TestNumeric < Test::Unit::TestCase
     end
     assert_equal(-1, -a)
 
+    bug7688 = '[ruby-core:51389] [Bug #7688]'
+    DummyNumeric.class_eval do
+      remove_method :coerce
+      def coerce(x); raise StandardError; end
+    end
+    assert_raise_with_message(TypeError, /can't be coerced into /) { 1 + a }
+    warn = /will no more rescue exceptions of #coerce.+ in the next release/m
+    assert_warn(warn, bug7688) { assert_raise(ArgumentError) { 1 < a } }
+
+    DummyNumeric.class_eval do
+      remove_method :coerce
+      def coerce(x); :bad_return_value; end
+    end
+    assert_raise_with_message(TypeError, "coerce must return [x, y]") { 1 + a }
+    warn = /Bad return value for #coerce.+next release will raise an error/m
+    assert_warn(warn, bug7688) { assert_raise(ArgumentError) { 1 < a } }
+
   ensure
     DummyNumeric.class_eval do
       remove_method :coerce