Re: zgrep -<NUM> doesn't work if <NUM> is two digits or greater

[Thomas Bushnell, BSG]

Cool. Dan Bloch should get the credit for finding the bug I believe.


On Tue, Aug 7, 2012 at 10:24 AM, Jim Meyering <address@hidden> wrote:

> Jim Meyering wrote:
> > Thomas Bushnell, BSG wrote:
> >> Create a gzipped file:
> >>
> >>    $ for i in $(seq 1 100); do echo $i; done > file.txt
> >>    $ gzip file.txt
> >>
> >> Then:
> >>
> >>    $ zgrep -9 17 file.txt.gz
> >>    8
> >>    9
> >>    ...
> >>    25
> >>    26
> >>
> >> works.  But:
> >>
> >>    $ zgrep -10 17 file.txt.gz
> >>    gzip: 17.gz: No such file or directory
> >>
> >> fails.
> >>
> >> Note that "grep -9 17 file.txt" and "grep -10 17 file.txt" work just
> >> fine.
> >>
> >> (https://bugs.launchpad.net/bugs/1032831)
> >>
> >> Please include me in the CC on any replies.
> >
> > Hi Thomas,
> >
> > Thanks for the report.
> > That made a nice puzzle to go with my morning caffeine ;-)
> >
> > Here's the fix:
> > I'll write the NEWS entry and test later.
>
> Here's the complete patch I expect to push:
>
> From 722184b17c98080c66453d4568bf37165108ad06 Mon Sep 17 00:00:00 2001
> From: Jim Meyering <address@hidden>
> Date: Tue, 7 Aug 2012 10:21:55 +0200
> Subject: [PATCH 1/2] zgrep: handle a multi-digit context option like -15
>
> * zgrep.in: Do not malfunction when given an option like -15.
> Before, it could mistake the pattern for a file name:
>
>   $ echo x | gzip | zgrep -15 x
>   gzip: x.gz: No such file or directory
>
> * NEWS (Bug fixes): Mention it.
> Reported by Thomas Bushnell: https://bugs.launchpad.net/bugs/1032831
> ---
>  NEWS     |  4 ++++
>  zgrep.in | 10 +++++++---
>  2 files changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/NEWS b/NEWS
> index ac39994..79c1110 100644
> --- a/NEWS
> +++ b/NEWS
> @@ -4,6 +4,10 @@ GNU gzip NEWS                                    -*-
> outline -*-
>
>  ** Bug fixes
>
> +  zgrep no longer malfunctions with a multi-digit context option like -15.
> +  Now, it passes that option to grep (equivalent to -C15) just as it does
> +  for single-digit options. [bug introduced in gzip-1.3.12]
> +
>    zmore now acts more like 'more', and is more portable to POSIXish hosts.
>
>
> diff --git a/zgrep.in b/zgrep.in
> index d09bfa7..abc5847 100644
> --- a/zgrep.in
> +++ b/zgrep.in
> @@ -66,9 +66,13 @@ while test $# -ne 0; do
>
>    case $option in
>    (-[0123456789EFGHIKLPRTUVZabchilnoqrsuvwxyz]?*)
> -    arg2=-\'$(expr "X$option" : 'X-.[0-9]*\(.*\)' | sed "$escape")
> -    eval "set -- $arg2 "'${1+"$@"}'
> -    option=$(expr "X$option" : 'X\(-.[0-9]*\)');;
> +    if expr "X$option" : 'X-[0-9]\+$' > /dev/null; then
> +      : # Let a multi-digit, digit-only option like -10 fall through.
> +    else
> +      arg2=-\'$(expr "X$option" : 'X-.[0-9]*\(.*\)' | sed "$escape")
> +      eval "set -- $arg2 "'${1+"$@"}'
> +      option=$(expr "X$option" : 'X\(-.[0-9]*\)')
> +    fi;;
>    (--binary-*=* | --[lm]a*=* | --reg*=*)
>      ;;
>    (-[ABCDXdefm] | binary-* | --file | --[lm]a* | --reg*)
> --
> 1.7.12.rc1.22.gbfbf4d4
>
>
> From 71b69de01f6799280b9131bb5882971e53c99fcd Mon Sep 17 00:00:00 2001
> From: Jim Meyering <address@hidden>
> Date: Tue, 7 Aug 2012 18:29:14 +0200
> Subject: [PATCH 2/2] tests: exercise the just-fixed part of zgrep
>
> * tests/zgrep-context: New file.
> * tests/Makefile.am (TESTS): Add it.
> ---
>  tests/Makefile.am   |  1 +
>  tests/zgrep-context | 43 +++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 44 insertions(+)
>  create mode 100755 tests/zgrep-context
>
> diff --git a/tests/Makefile.am b/tests/Makefile.am
> index 3b6ec31..ddab493 100644
> --- a/tests/Makefile.am
> +++ b/tests/Makefile.am
> @@ -25,6 +25,7 @@ TESTS =                                       \
>    trailing-nul                         \
>    zdiff                                        \
>    zgrep-f                              \
> +  zgrep-context                                \
>    zgrep-signal                         \
>    znew-k
>
> diff --git a/tests/zgrep-context b/tests/zgrep-context
> new file mode 100755
> index 0000000..85799a4
> --- /dev/null
> +++ b/tests/zgrep-context
> @@ -0,0 +1,43 @@
> +#!/bin/sh
> +# Ensure that zgrep -15 works.  Before gzip-1.5, it would fail.
> +
> +# Copyright (C) 2012 Free Software Foundation, Inc.
> +
> +# This program is free software: you can redistribute it and/or modify
> +# it under the terms of the GNU General Public License as published by
> +# the Free Software Foundation, either version 3 of the License, or
> +# (at your option) any later version.
> +
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +# GNU General Public License for more details.
> +
> +# You should have received a copy of the GNU General Public License
> +# along with this program.  If not, see <http://www.gnu.org/licenses/>.
> +# limit so don't run it by default.
> +
> +. "${srcdir=.}/init.sh"; path_prepend_ ..
> +
> +require_POSIX_grep_
> +
> +# A limited replacement for seq: handle 1 or 2 args, and an increment of
> 1.
> +seq()
> +{
> +  case $# in
> +    1) start=1  final=$1;;
> +    2) start=$1 final=$2;;
> +    *) echo you lose 1>&2; exit 1;;
> +  esac
> +  awk 'BEGIN{for(i='$start';i<='$final';i++) print i}' < /dev/null
> +}
> +
> +seq 40 > in || framework_failure_
> +gzip < in > in.gz || framework_failure_
> +seq 2 32 > exp || framework_failure_
> +
> +fail=0
> +zgrep -15 17 - < in.gz > out || fail=1
> +compare exp out || fail=1
> +
> +Exit $fail
> --
> 1.7.12.rc1.22.gbfbf4d4
>