bug#15773: grep-2.15 bug report

[Aharon Robbins]

Hello All.

> >>> After updating from 2.14 to 2.15 grep has started to fail to match 
> >>> patterns
> >>> that contain '\s*' or '\s\+'
>
> And here's a proper patch, including NEWS and test suite additions:

FWIW, I can't reproduce this in gawk (gawk-4.1-stable branch).

The program below correctly produces no output, with and without the fix
in dfa.c:lex. (I have added the fix anyway.)

Any ideas why?

Thanks,

Arnold
----------------------------------
BEGIN {
        pat["^\\s*$"] = pat["^\\s+$"] = pat["^\\s?$"] = pat["^\\s{1}$"] = 1
        for (i in pat) {
                if (" " !~ i) {
                        printf("pattern \"%s\" failed!\n", i) > "/dev/stderr"
                        exit 1
                }
        }
        exit 0
}