bug#19252: [PATCH] dfa: matching at next position or infinit loop in matching mode

[Jim Meyering]

On Wed, Dec 3, 2014 at 2:18 AM, Norihiro Tanaka <address@hidden> wrote:
> On Tue, 2 Dec 2014 08:35:32 -0800
> Jim Meyering <address@hidden> wrote:
>> I'm not sure I understand the above paragraph.
>> Is this what you intended?
>>
>>     That will cause an invalid match or an infinite loop.
>>     By the way, there is no option to make grep use
>>     searching mode rather than matching mode.
>
> That will cause an invalid match or an infinite loop.
> By the way, there is no option to make grep use
> matching mode rather than searching mode.
>
>> Can you provide a test case to trigger this?
>> Is it easier to construct a test case using gawk?
>
> Yes, but it uses neither grep nor gawk.  It uses an auxiliary program
> writtern only to accomplish the test, as grep and gawk do *NOT* set 0 to
> forth argument of dfacomp.  I added tests of failure and infloop version.

Thank you for adding that test program and a script to run it.
I have made some changes:

  - reworded the commit logs
  - removed the NEWS entry, since this is not a user-visible change
  - changed a 4-line sequence in dfa.c to a single one using the
      ternary operator:

     -      if (allow_nl)
     -        s = d->newlines[s1];
     -      else
     -        s = 0;
     +      s = allow_nl ? d->newlines[s1] : 0;

  - fixed the new "make syntax-check" violations induced
      by the addition of that new .c file.
  - changed the test script to use warn_ rather than printf
  - replaced the full hex SHA1 in the log with the more useful
      and readable "git desc ..." output: v2.5.4-144-gbafa134

See attached:

0001-dfa-avoid-invalid-match-or-infinite-loop-in-unused-m.patch
Description: Binary data

0002-dfa-simplify-dfaexec.patch
Description: Binary data