Issue #12728 has been reported by Robert Klemme.

----------------------------------------
Bug #12728: Negative lookahead does not work for "+" even though works for "@"
https://bugs.ruby-lang.org/issues/12728

* Author: Robert Klemme
* Status: Open
* Priority: Normal
* Assignee: 
* ruby -v: ruby 2.2.5p319 (2016-04-26 revision 54774) [x86_64-cygwin]
* Backport: 2.1: UNKNOWN, 2.2: UNKNOWN, 2.3: UNKNOWN
----------------------------------------
I'll attach a test program that shows the effect.  Basically, if I have a negative lookahead in the regex like (?!@) and "@" shows up in the proper location I get a mismatch (1. case).  This is expected.  If I exchange the "@" with a "\+" or "[+]" in the regex and a "+" in the input, a match occurs (case 2 and 3).  This is the bug.  If the "+" or "@" is removed from the string an expected match occurs (case 4 and 5).  I was not able to boil this down to a smaller example yet.

---Files--------------------------------
rx-mini.rb (1.63 KB)


-- 
https://bugs.ruby-lang.org/

Unsubscribe: <mailto:ruby-core-request / ruby-lang.org?subject=unsubscribe>
<http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>