Path: csiph.com!goblin1!goblin.stu.neva.ru!usenet.stanford.edu!not-for-mail
From: Grisha Levit <grishalevit@gmail.com>
Newsgroups: gnu.bash.bug
Subject: null array[*] expansion not treated as null
Date: Mon, 12 Nov 2018 16:32:06 -0500
Lines: 13
Approved: bug-bash@gnu.org
Message-ID: <mailman.3945.1542058363.1284.bug-bash@gnu.org>
NNTP-Posting-Host: lists.gnu.org
Mime-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
X-Trace: usenet.stanford.edu 1542058364 4057 208.118.235.17 (12 Nov 2018 21:32:44 GMT)
X-Complaints-To: action@cs.stanford.edu
To: bug-bash <bug-bash@gnu.org>
Envelope-to: bug-bash@gnu.org
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:from:date:message-id:subject:to; bh=6bV8BVtET4MkiIxhQGWfdciGIhs2Ho2BQ5PhGlm/iqc=; b=WHPS55TJQUrBPY95kTZfqhNlEBWTExgyz5nwMveLxX2x3rFS3dop4q+bgEGIKseHta sd8kxVMsv0+KGVezYOdTQSyISk6sn8l6NKJjawkOnieHBKOYOGd+L/BSVjR8s02NEJeU eoLJbi/LIa6uamXnb8uxxz+/wi5g+pck/cOUfJoTeP/xx5OdTdVF97LBrDHCwlv0DKzz rfYXlp4sjEo3VrLZao0Np+MysaR2eAgV8jkXJ+BeE8ak9P5gGRPIeizkIXZ+bamrYFLk leGdqjA7kJFpHNTr8/RdyR1Tw4KPa+sCyo8o+A/+kAkyCUHOAWDgyGDywDbK/kBvvaAx w7KA==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to; bh=6bV8BVtET4MkiIxhQGWfdciGIhs2Ho2BQ5PhGlm/iqc=; b=gflYDLBTxAdI5JLAg7wfxoXtjNXIZooqfi4IkNmMYTQFp7trH7KwN1TCv6FKQvERnT XtoO4iHhHEk/uS4IYhRMURRBpQnR+8IL1z+JXwVge9OYv8rm98CskZdn5RA+yCIdWVcu Ewo7BJnp2D1tp2fTHEfh0IJ/GG64m9fQanB3i5D/nqHvT3MLTgNPKaaoK8borcM1oZel kpWjEJknon/UWzqyulP2T+307IKE74EFm2dUSxaotkLeFGQHejCqZU4cgdevFkaSiF7r dCRbbAJu2m8AcMDouQk+bCd5AAdiU3tUlHlwTn6UuPJxyWMURPdsigSGd7DEF6haIa/Z iUxQ==
X-Gm-Message-State: AGRZ1gLBlRn4MTdsKMGgM2vcgfv32JDCwouM13h5snjvQhthN+8acJ57 Ml6gEa2lyO4N1oOkIJeXam/x5VO7Cizvf+MumQDfP/QRKBc=
X-Google-Smtp-Source: AJdET5dgALeubTOoL5YOWP6h/Asl0j3BETeWroeTHDaQVS6Kb3d+RcgB6+XUcCmhDBl2PivI9wi+N0wpYvPuXlz0/KE=
X-Received: by 2002:ac8:30ac:: with SMTP id v41mr2507149qta.51.1542058337666; Mon, 12 Nov 2018 13:32:17 -0800 (PST)
X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized.
X-Received-From: 2607:f8b0:4864:20::72e
X-Content-Filtered-By: Mailman/MimeDel 2.1.21
X-BeenThere: bug-bash@gnu.org
X-Mailman-Version: 2.1.21
Precedence: list
List-Id: Bug reports for the GNU Bourne Again SHell <bug-bash.gnu.org>
List-Unsubscribe: <https://lists.gnu.org/mailman/options/bug-bash>, <mailto:bug-bash-request@gnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/archive/html/bug-bash/>
List-Post: <mailto:bug-bash@gnu.org>
List-Help: <mailto:bug-bash-request@gnu.org?subject=help>
List-Subscribe: <https://lists.gnu.org/mailman/listinfo/bug-bash>, <mailto:bug-bash-request@gnu.org?subject=subscribe>
Xref: csiph.com gnu.bash.bug:14805

When an array A has non-zero elements but the expansion of "${A[*]}" is
still
a null string, it is not treated as such for purposes of ${var:-X} expansion
(though $* is treated as null in the same circumstance).

    $ A=(''); set -- ''
    $ echo "<${A[*]:-X}>" "<${*:-X}>"
    <> <X>

    $ IFS=
    $ A=('' ''); set -- '' ''
    $ echo "<${A[*]:-X}>" "<${*:-X}>"
    <> <X>