Path: csiph.com!goblin3!goblin2!goblin1!goblin.stu.neva.ru!usenet.stanford.edu!not-for-mail
From: =?utf-8?Q?Lawrence_Vel=C3=A1zquez?= <vq@larryv.me>
Newsgroups: gnu.bash.bug
Subject: Re: set -u not working as expected
Date: Sun, 2 Aug 2020 01:12:56 -0400
Lines: 52
Approved: bug-bash@gnu.org
Message-ID: <mailman.481.1596345182.2739.bug-bash@gnu.org>
References: <000301d66834$588493c0$098dbb40$@kalvr.net> <F4821044-5F8D-4B6D-A266-BAC88AE3DC2C@larryv.me> <1867D8FC-85DD-4406-A239-3002913493AB@larryv.me>
NNTP-Posting-Host: lists.gnu.org
Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.15\))
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
Cc: bug-bash@gnu.org
To: Kristof Burek <contact@kalvr.net>
Envelope-to: bug-bash@gnu.org
In-Reply-To: <F4821044-5F8D-4B6D-A266-BAC88AE3DC2C@larryv.me>
Received-SPF: pass client-ip=64.147.123.25; envelope-from=vq@larryv.me; helo=wout2-smtp.messagingengine.com
X-Spam_score_int: -27
X-Spam_score: -2.8
X-Spam_bar: --
X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=ham autolearn_force=no
X-Spam_action: no action
X-BeenThere: bug-bash@gnu.org
X-Mailman-Version: 2.1.23
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: <https://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>
X-Mailman-Original-Message-ID: <1867D8FC-85DD-4406-A239-3002913493AB@larryv.me>
X-Mailman-Original-References: <000301d66834$588493c0$098dbb40$@kalvr.net> <F4821044-5F8D-4B6D-A266-BAC88AE3DC2C@larryv.me>
Xref: csiph.com gnu.bash.bug:16672

> On Aug 1, 2020, at 8:47 PM, Lawrence Vel=C3=A1zquez <vq@larryv.me> =
wrote:
>=20
> Presumably none of these shells implements u+=3D(t) as u=3D("${u[@]}" =
t).

Granted, they do disagree on ${u[@]}.

% bash -c 'set -u; unset u; u=3D("${u[@]}" t); typeset -p u'
declare -a u=3D([0]=3D"t")
% ksh -c 'set -u; unset u; u=3D("${u[@]}" t); typeset -p u'
typeset -a u=3D(t)
% zsh -c 'set -u; unset u; u=3D("${u[@]}" t); typeset -p u'
zsh:1: u[@]: parameter not set

> I haven't seen the code for arithmetic expansion, but I assume it
> treats v+=3D1 as morally equivalent to v=3D${v}+1 (=C3=A0 la C99). =
Thus there
> *is* an expansion, which fails under set -u. Regardless of the
> particulars, ksh and zsh again agree:
>=20
> % bash -c 'set -u; unset v; let v+=3D1; printf "<%s>\\n" "$v"'
> bash: v: unbound variable
> % ksh -c 'set -u; unset v; let v+=3D1; printf "<%s>\\n" "$v"'
> ksh: let: v: parameter not set
> ksh: v: parameter not set
> % zsh -c 'set -u; unset v; let v+=3D1; printf "<%s>\\n" "$v"'
> zsh:1: v: parameter not set
> zsh:1: v: parameter not set

On the other hand...

% bash -c 'set -u; typeset -i v; printf "<%s>\\n" "$v"'
bash: v: unbound variable
% ksh -c 'set -u; typeset -i v; printf "<%s>\\n" "$v"'
ksh: v: parameter not set
% zsh -c 'set -u; typeset -i v; printf "<%s>\\n" "$v"'
<0>

...and...

% bash -c 'set -u; typeset -i v; v+=3D1; printf "<%s>\\n" "$v"'
<1>
% ksh -c 'set -u; typeset -i v; v+=3D1; printf "<%s>\\n" "$v"'
<1>
% zsh -c 'set -u; typeset -i v; v+=3D1; printf "<%s>\\n" "$v"'
<1>

*shrug*

vq=