From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 23190 invoked by alias); 17 Apr 2018 09:20:09 -0000 Mailing-List: contact zsh-workers-help@zsh.org; run by ezmlm Precedence: bulk X-No-Archive: yes List-Id: Zsh Workers List List-Post: List-Help: List-Unsubscribe: X-Seq: 42666 Received: (qmail 19741 invoked by uid 1010); 17 Apr 2018 09:20:09 -0000 X-Qmail-Scanner-Diagnostics: from mailout1.w1.samsung.com by f.primenet.com.au (envelope-from , uid 7791) with qmail-scanner-2.11 (clamdscan: 0.99.2/21882. spamassassin: 3.4.1. Clear:RC:0(210.118.77.11):SA:0(-1.9/5.0):. Processed in 15.156442 secs); 17 Apr 2018 09:20:09 -0000 X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on f.primenet.com.au X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,RCVD_IN_MSPIKE_H2, SPF_HELO_PASS,SPF_PASS,T_DKIMWL_WL_HIGH,T_DKIM_INVALID autolearn=ham autolearn_force=no version=3.4.1 X-Envelope-From: p.stephenson@samsung.com X-Qmail-Scanner-Mime-Attachments: | X-Qmail-Scanner-Zip-Files: | DKIM-Filter: OpenDKIM Filter v2.11.0 mailout1.w1.samsung.com 20180417091950euoutp01a7d41c5dbe53f36c6863ac90a229f706~mLqCHUQbA2259122591euoutp01j DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1523956790; bh=pFNsWnLjwN7xl7J8cN80NweeGUzgZINbMB8DDAwh540=; h=Date:From:To:Subject:In-reply-to:References:From; b=jmgGu+iKjMNeUvdU6cPQc/gIdVn8MtXv56Q10YXX+rtguGEVoKlJdoVH0TfOTZ0ZD M+StHY+O4My/3QRNwqf/Id6DYcN1l3KiXTdOM10yKApFS1I1MWFrNb1eGkPiNskBVl kxYcjVtLA8PKgrq4f9pnCQOnD23tWjCirxQIG7kc= X-AuditID: cbfec7f5-b45ff700000028a9-14-5ad5bc35169e Date: Tue, 17 Apr 2018 10:19:47 +0100 From: Peter Stephenson To: zsh-workers@zsh.org Subject: Re: "echo | ps -j $(:) | cat | cat | cat" runs components in different process groups Message-id: <20180417101947.5fd347df@camnpupstephen.cam.scsc.local> In-reply-to: <180416223910.ZM32002@torch.brasslantern.com> Organization: SCSC X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-version: 1.0 Content-type: text/plain; charset="US-ASCII" Content-transfer-encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrCIsWRmVeSWpSXmKPExsWy7djPc7qme65GGbxsMrU42PyQyYHRY9XB D0wBjFFcNimpOZllqUX6dglcGVfOHmUumMZZ0dwzhbmBsYW9i5GDQ0LAROLVxeouRi4OIYEV jBKr571k62LkBHJ6mSRmrNEFsUFqVjT3MUEULWOUWPBxAxuEM41J4tzUuSwQzhlGicXHVzNC OBcYJZ48+sYE0s8ioCqx78JcZhCbTcBQYuqm2YwgtoiAuMTZtedZQGxhgQSJs3t2gNXzCjhL rJj8D8zmFLCS2DgTJM7BwS8gJHGh2RbiJHuJo3tOQpULSvyYfA9sDLOAjsS2bY/ZIWx5ic1r 3jKD3CMhMIVNYuaibmaIZheJVd86GCFsYYlXx7ewQ9gyEp0dB5kgGpoZJdbev88GkehhlJi1 OBTCtpbou32REWIDn8SkbdOZIQHJK9HRJgRR4iFx7dJnqJmOEqv2trFCAmUKq0T/+/8sExjl ZyE5fBaSw2chOXwBI/MqRvHU0uLc9NRi47zUcr3ixNzi0rx0veT83E2MwLg//e/41x2M+/4k HWIU4GBU4uGV2HElSog1say4MvcQowQHs5II787HQCHelMTKqtSi/Pii0pzU4kOM0hwsSuK8 cRp1UUIC6YklqdmpqQWpRTBZJg5OqQbG6zkPc5Jf2c90N381UTi1OGf14n3/NrPlTuiMDj5l cqX8SNLnHscstQfV7+vlc92uMT48a7PuBX+VaILNO97/181f3JB56m93svzggcT3p1dbaKor f8/mvfoh81qexJ6780J0TK45BPZxvjrhYt/9+HyPf8w27sS5uWINx57ZS3UW3K3/GfBRiaU4 I9FQi7moOBEALKOTXvcCAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFjrMLMWRmVeSWpSXmKPExsVy+t/xq7qme65GGVx9ImxxsPkhkwOjx6qD H5gCGKO4bFJSczLLUov07RK4Mq6cPcpcMI2zorlnCnMDYwt7FyMnh4SAicSK5j6mLkYuDiGB JYwS/3bOgXJmMElsfXWDBaRKSOAco8SKn4kQiQuMEu/efWAGSbAIqErsuzAXzGYTMJSYumk2 I4gtIiAucXbtebBmYYEEiUVPJoDFeQWcJVZM/scEYnMKWElsnLkDatsUVomObd+Aijg4+AWE JC4020KcZy9xdM9JJoheQYkfk++BzWQW0JLYvK2JFcKWl9i85i0zxKHqEjfu7mafwCg0C0nL LCQts5C0LGBkXsUoklpanJueW2yoV5yYW1yal66XnJ+7iREYtNuO/dy8g/HSxuBDjAIcjEo8 vBI7rkQJsSaWFVfmHmKU4GBWEuHd+RgoxJuSWFmVWpQfX1Sak1p8iFGag0VJnPe8QWWUkEB6 YklqdmpqQWoRTJaJg1OqgTFqEuu75rbENQdFdVbdes/4+pl4zIVbxjZ7/xxQ4d2lGip2WlRi vn7K+ZbDXEVsB0/ZWv6+lOf8qFm86Ja8/qZrzzYu+eR46Ni5ab+fbN0YIHdoCd+vgKVCc5bP fH/c8sSmW0bbT3B+/s/GzaF+qlEtUWLecdd9DzqcpHsk3q61XfDjhLzMZaU+JZbijERDLeai 4kQAuOYY4VYCAAA= X-CMS-MailID: 20180417091949eucas1p295f46ac1670cd4bfec428d6b02d916aa X-Msg-Generator: CA CMS-TYPE: 201P X-CMS-RootMailID: 20180324221021epcas1p184507a6328dbd505b97db69c1f9d8194 X-RootMTR: 20180324221021epcas1p184507a6328dbd505b97db69c1f9d8194 References: <180323221959.ZM27569@torch.brasslantern.com> <20180324080514.txxyrb3qiztu4pqt@gmail.com> <180324150945.ZM32251@torch.brasslantern.com> <20180410124545.13fccd5d@camnpupstephen.cam.scsc.local> <20180410145926.64c4f671@camnpupstephen.cam.scsc.local> <180411151025.ZM19332@torch.brasslantern.com> <20180412172342.52df6b10@camnpupstephen.cam.scsc.local> <20180415162326.GA12549@chaz.gmail.com> <20180415185804.GB12549@chaz.gmail.com> <180416223910.ZM32002@torch.brasslantern.com> On Mon, 16 Apr 2018 22:39:10 -0700 Bart Schaefer wrote: > So if, when we determine that "&" is the command separator, we could > treat the command in the way the "time" prefix does, this would all > work out without mangling execcmd_exec() and prefork(). That's good, I think that's probably worth doing. > However, there are some other unique zsh-isms that would be altered > by this. For example: > > % echo ${foo::=bar} & echo $foo > [1] 31940 > bar > % bar > > [1] + done echo ${foo::=bar} > % unset foo > % time echo ${foo::=bar} & echo $foo > [1] 31943 > > % bar > > [1] + done time echo ${foo::=bar} > % > > Note the assignment "sticks" in the current shell in the first case, > because it happens before the fork, but is lost in the second case. > Perhaps the former is a bug as well. It certainly looks rather unexpected. I think most of us staring at it would assume the entire command line was evaluated in the background. It's hard to believe anyone is deliberately relying on this behaviour. I think it would be fine to change with a note about the incompatibility. pws