Re: grep-2.6.2 -Ff hangs on files with empty lines

[Jim Meyering]

Allan McRae wrote:
> On 31/03/10 16:21, Jim Meyering wrote:
>> Allan McRae wrote:
>>> Grep-2.6.2 will hang on "grep -Ff foo bar" if foo contains an empty
>>> line.  The bug is new to 2.6.2.
>>
>> Thanks for the report.
>> However, so far, I am unable to reproduce that.
>>
>> Please provide more details:
>>    - type of CPU and OS you are using
>
> I am running Arch Linux and get the issue on both i686 and x86_64.
> Grep is configured with:
> ./configure --prefix=/usr --bindir=/bin --without-included-regex
>
>>    - the contents of your "foo" and "bar" files
>
> I replicate using your example:
>
> printf 'a\n\nb\n' > foo
> seq 10 > bar
> grep -Ff foo bar


I don't have an Arch Linux system handy, so
I rebuilt --without-included-regex on F11, F12, F13-alpha, rawhide,
and a couple of debian and even a Centos 5.4 system.
On all of them, I saw this (and no hang):

    $ printf 'a\n\nb\n' > foo; seq 10 > bar; src/grep -Ff foo bar
    1
    2
    3
    4
    5
    6
    7
    8
    9
    10

I suspect something about your system.  The compiler?
Did grep's "make check" pass?

Please run it under gdb and send a backtrace showing where it's hanging.