From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 92944 invoked by alias); 6 Apr 2018 19:22:49 -0000 Mailing-List: contact cygwin-developers-help@cygwin.com; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-developers-owner@cygwin.com Mail-Followup-To: cygwin-developers@cygwin.com Received: (qmail 92928 invoked by uid 89); 6 Apr 2018 19:22:48 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.6 required=5.0 tests=BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 spammy=persons, tweaked, preferences, cells X-HELO: mout.gmx.net Received: from mout.gmx.net (HELO mout.gmx.net) (212.227.17.21) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Fri, 06 Apr 2018 19:22:46 +0000 Received: from [192.168.0.129] ([37.201.195.115]) by mail.gmx.com (mrgmx101 [212.227.17.168]) with ESMTPSA (Nemesis) id 0Lo2EO-1ebnuF2Wfw-00fwUr; Fri, 06 Apr 2018 21:22:43 +0200 Date: Fri, 06 Apr 2018 19:22:00 -0000 From: Johannes Schindelin To: Thomas Wolff cc: cygwin-developers@cygwin.com Subject: Re: winpty injection In-Reply-To: <8dbc29b9-eb6e-9385-9ef4-cd7bc00099f2@towo.net> Message-ID: References: <20180405084733.GP2833@calimero.vinschen.de> <848d804d-8dad-a176-4fa9-a51e1544da3a@towo.net> <075cb1a4-7508-306b-a3a6-a1d9db939ba9@towo.net> <8dbc29b9-eb6e-9385-9ef4-cd7bc00099f2@towo.net> User-Agent: Alpine 2.21.1 (DEB 209 2017-03-23) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-UI-Out-Filterresults: notjunk:1;V01:K0:zDqit6hO3Nk=:PqwAp/R98kAZr3NkeltkxK hjsBrZvBFMtwQu6vfIvXY72PupEsH03OPRLeUx/bYghGlKsYhmFh43mhLLRmRq8VqXHSdxJIe ao0222GAgtHPoe2rF07rfZWJOHztLnkCx4lDulJwXiD2XBVecLiFVxt1wmyCExOVS4JP8b2Lw 3iYPSip4/+nhLPLfqGyRGkcQ53pI92NNZysOo1bU3xmZ8zAc+iOlrflyVlyI7bVpEXTEqqsvo yFBI984L8MlPSmpFHYDzSQqouJm6sjrwRTKufTSfuQc+SCYXHo5cOTx95GlFs92OSqpytjwmV 8KWr6/keB3X4r1PLVA8NPfI18Ng32s7dYgpEtWKV8XA8yQpFdr+fnUtA7EpryHdS153pKsVC6 wy2NjR1T/v/QCvNvhu4BaCcoEg2+XyJzW4jWKwsp67aaYAyeOHddS7c/A14FhQKlIwDmwZ4V0 UbAwbeBOAyp5B4oBCrq6eXYGYaTAp/OUO5kO23axMjwEXtVS6r6vP97EUKwXH4HinbPCPrx6i cxEHdkZLUlNZnDaMK8c2UZUOiuMImwWq793BaXAli8JwRLkiLJZVkNJT8+xTwrDnOGOZuprZi 1PMvgFRw2aFCDTvW5Hx3qhBV07flXz7xF8EOa6R6+fJc6yFJmsgs+UbLsLURX5CNM1GZnFncz 9TMA/D1DWjPvZhZtH+Sv7b9oNLQ87Sq9xIebwz7vH83EIaKIX5X7BQl+A5Rs+nGkKVuKRAvrQ LCdRmpSBhV5byik8DjlCd1bX3IVO1nn5rsvS57Ap9V8j/JMv4w0EBL09WsWBibiBAhE6WYp7I i3AGpMxBK5PXZN14m1ES70TmpOne9sVJ1CNVFPfnfclTMOBbfAyoWyzUpRE6hrWnnE8KsTr X-IsSubscribed: yes X-SW-Source: 2018-04/txt/msg00015.txt.bz2 Hi Thomas, On Fri, 6 Apr 2018, Thomas Wolff wrote: > Am 06.04.2018 um 12:31 schrieb Johannes Schindelin: > > > > On Fri, 6 Apr 2018, Thomas Wolff wrote: > > > > > These symptoms suggest to me: winpty is not the culprit, but its > > > presence in the invocation chain seems to trigger the effect in a > > > yet unclear way. > > > > Sure, `winpty` is not the culprit. > > > Actually, as it turns out, winpty *is* the culprit. I've raised winpty > issue https://github.com/rprichard/winpty/issues/140 about it. I am not sure you understand the issue here. The `winpty` helper opens a Win32 console for the native Windows application to use. Then it polls this (hidden) console for changes and tries to reflect them in the Cygwin pty. If that Windows application writes something to that console containing Escape sequences, then those Escape sequences occupy certain cells in that matrix of rows and columns making up that console. However, if the Windows application uses random-access functions to put individual characters into cells specified by given absolute positions, winpty cannot tell the difference. So what winpty would be asked to consider an ANSI sequence may never have been an ANSI sequence. Sure, this is a construed example, but it shows that you should not be so sure that winpty *can* detect ANSI sequences and handle them in a way that *you* want. Apart from that, winpty's polling also adds quite a bit of a performance burden, using more CPU, and lagging in screen updates. Which some users do not take kindly to. > > But running certain software (such as Maven) through `winpty` is *not* > > as unproblematic as we would want. > > > > Therefore, it would make sense *not* to make it the default. Unless > > you have a really good strategy in mind how to communicate this change > > to users in a way that lets them know about this issue and how to work > > around it. > > Assuming, we're getting winpty tweaked as to the above issue, any further > concerns? Just like you seem to have a preference for removing all the structure of my mails when quoting them by removing all the empty lines, making things substantially harder to read for me (not to mention uglier to my eyes), this issue boils down to a matter of personal preferences. For an individual person, therefore, it would be totally appropriate to change the default on a whim, according to one person's personal bias. But not for a widely-used software such as Cygwin. In the least, therefore, it should be configurable. And I would even argue that the default behavior should remain the same as current in Cygwin: do not use winpty by default. Of course, this is just my opinion, and I am but a user and infrequent contributor to Cygwin. But I would hope that the Cygwin maintainers use a lot of care and reluctant deliberation when considering a potentially disruptive change such as this, a change that may very well occupy a lot of time in dealing with the unwanted fallout. Ciao, Johannes