error.c: Let Exception#inspect inspect its message

... only when the message string has a newline.

`p StandardError.new("foo\nbar")` now prints `#<StandardError: "foo\nbar">'
instead of:

    #<StandardError:
    bar>

[Bug #18170]

1 files changed, 6 insertions, 0 deletions

diff --git a/test/ruby/test_exception.rb b/test/ruby/test_exception.rb
index 0b05ff7c51..acc3228e2f 100644
--- a/test/ruby/test_exception.rb
+++ b/test/ruby/test_exception.rb
@@ -478,6 +478,12 @@ end.join
       def to_s; ""; end
     end
     assert_equal(e.inspect, e.new.inspect)
+
+    # https://bugs.ruby-lang.org/issues/18170#note-13
+    assert_equal('#<Exception:"foo\nbar">', Exception.new("foo\nbar").inspect)
+    assert_equal('#<Exception: foo bar>', Exception.new("foo bar").inspect)
+    assert_equal('#<Exception: foo\bar>', Exception.new("foo\\bar").inspect)
+    assert_equal('#<Exception: "foo\nbar">', Exception.new('"foo\nbar"').inspect)
   end
 
   def test_to_s