Re: bug on {,} : result of {,10} compar to {5,10},

[Eric Blake]

On 04/18/2013 10:46 AM, Paul Eggert wrote:
> On 04/18/13 08:24, Eric Blake wrote:
>> {,10} is therefore undefined by POSIX.
> 
> It is defined in the grep manual (in the
> node Fundamental Structure), as being
> equivalent to {0,10}, so there does appear
> to be a bug here.

Indeed, we have changed behavior over time; my Fedora 18 box has nicer
behavior:

$ rpm -q grep
grep-2.14-1.fc18.x86_64
$ echo guillaumeeeeeeeguillaume | grep -E "guillaume{,10}gui"
guillaumeeeeeeeguillaume

Guillaume was using grep 2.6.3 on Cygwin.  I don't directly see it in
grep's NEWS, although one of these two releases is probably responsible:

2.12:
  grep -E 'a{1000000000}' now reports an overflow error rather than
  silently acting like grep -E 'a\{1000000000}'.

2.7:
  X{0,0} is implemented correctly.  It used to be a synonym of X{0,1}.
  [bug present since "the beginning"]

At this point, it might be worth asking the Cygwin folks to package a
newer grep, to pick up this (and other) fixes, but there's nothing to do
upstream, unless we want to improve old NEWS entries.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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