From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Qiantan Hong Newsgroups: gmane.emacs.devel Subject: Re: Question collaborative editing. Date: Wed, 30 Sep 2020 17:48:13 +0000 Message-ID: <0B69D727-B2C1-44FC-8382-FDAB6C7CBDAD@mit.edu> References: <20200924013655.asv2tem25cbwv5et@Ergus> <2ACED303-9A2C-4363-BE56-2E9AF0B8DC85@posteo.net> <20200925002239.fgg3vw2nylltcoyp@Ergus> <219042AC-556D-48CC-8920-82D9BF2BD3AA@aol.com> <3A81FB67-A558-4281-8285-CDD9B01033E3@posteo.net> <1C949FC9-6023-467E-99EC-75D57B08AFB0@gnu.support> <20200929124513.fd745r2txowwbiir@Ergus> <87blho7af9.fsf@red-bean.com> <20200929215849.zg4wzytbrwx2b7ih@Ergus> <84B86B7C-81F0-42DF-894C-BF577E4B3D6E@mit.edu> <83a6x7js6y.fsf@gnu.org> <83eemji6e8.fsf@gnu.org> <83blhni3kr.fsf@gnu.org> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="Apple-Mail=_DB4A0434-406B-4009-904C-9E1FD049C8C8"; protocol="application/pkcs7-signature"; micalg=sha-256 Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="4973"; mail-complaints-to="usenet@ciao.gmane.io" Cc: Ergus , Fermin , Jean Louis , Noam Postavsky , Emacs developers , Karl Fogel , Stefan Monnier To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Wed Sep 30 19:50:18 2020 Return-path: Envelope-to: ged-emacs-devel@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kNgF8-0001Ay-PB for ged-emacs-devel@m.gmane-mx.org; Wed, 30 Sep 2020 19:50:18 +0200 Original-Received: from localhost ([::1]:36734 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kNgF7-0005vR-8X for ged-emacs-devel@m.gmane-mx.org; Wed, 30 Sep 2020 13:50:17 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:55100) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kNgDk-0004bK-4g for emacs-devel@gnu.org; Wed, 30 Sep 2020 13:48:52 -0400 Original-Received: from outgoing-exchange-5.mit.edu ([18.9.28.59]:52010) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kNgDh-0004fK-BA; Wed, 30 Sep 2020 13:48:51 -0400 Original-Received: from oc11exedge1.exchange.mit.edu (OC11EXEDGE1.EXCHANGE.MIT.EDU [18.9.3.17]) by outgoing-exchange-5.mit.edu (8.14.7/8.12.4) with ESMTP id 08UHmfcZ028861; Wed, 30 Sep 2020 13:48:44 -0400 Original-Received: from oc11expo16.exchange.mit.edu (18.9.4.47) by oc11exedge1.exchange.mit.edu (18.9.3.17) with Microsoft SMTP Server (TLS) id 15.0.1293.2; Wed, 30 Sep 2020 13:47:34 -0400 Original-Received: from oc11expo16.exchange.mit.edu (18.9.4.47) by oc11expo16.exchange.mit.edu (18.9.4.47) with Microsoft SMTP Server (TLS) id 15.0.1365.1; Wed, 30 Sep 2020 13:48:13 -0400 Original-Received: from oc11expo16.exchange.mit.edu ([18.9.4.47]) by oc11expo16.exchange.mit.edu ([18.9.4.47]) with mapi id 15.00.1365.000; Wed, 30 Sep 2020 13:48:13 -0400 Thread-Topic: Question collaborative editing. Thread-Index: AQHWkA+RtV3K1wr9B0aFczVHqkD+n6lzGC2+gAByx1WAA75ZgIABUIuAgAAtCoCAAKrvgIAEEd+AgAGGOACAABFAAIAAe9OAgABIs4CAAA5xVYAAjDuAgAAchYCAAKh2a4AAZX0A///GIeWAAE52AIAAAPKA///BnCeAAEq0gA== In-Reply-To: <83blhni3kr.fsf@gnu.org> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: yes x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [18.18.245.17] Received-SPF: pass client-ip=18.9.28.59; envelope-from=qhong@mit.edu; helo=outgoing-exchange-5.mit.edu X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/30 13:01:05 X-ACL-Warn: Detected OS = Windows 7 (Websense crawler) X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:256783 Archived-At: --Apple-Mail=_DB4A0434-406B-4009-904C-9E1FD049C8C8 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 > I'm sorry, I probably miss too much background information here, > because I don't really understand what is the issue you are describing > here. E.g., why is user intent important, when all you need is to > keep buffer text synchronized between several sessions? That=E2=80=99s the baseline for collaborative editing, there=E2=80=99s = apparently solution that satisfies this single property (convergence property) but are extremely bad =E2=80=94 e.g. the effect of some user input takes no effect, or a trivial program displaying an empty buffer for=20 every user. Actually if we only want this property there=E2=80=99s much simpler way than CRDT/OT, e.g. let the server (or one client) send the whole buffer periodically. One example of diff not preserving user intent is: suppose in the buffer there is =E2=80=9Cone two one=E2=80=9D And users agree that this sentence should always end in =E2=80=9Cone=E2=80= =9D. Now user A deleted the first two words =E2=80=9Cone two =E2=80=9C user B inserted =E2=80=9Cthree=E2=80=9D between the first =E2=80=9Cone=E2=80= =9D and =E2=80=9Ctwo=E2=80=9D However, the diff have no idea about users=E2=80=99 agreement and what exactly user does (unless we get it from modification hooks). For user A, the diff just see =E2=80=9Cone=E2=80=9D after and = assume that A delete the suffix =E2=80=9Ctwo one=E2=80=9D. The CRDT then does = it job correctly and gives final synchronization result =E2=80=9Cone three=E2=80=9D= . Clearly, user intent is violated.= --Apple-Mail=_DB4A0434-406B-4009-904C-9E1FD049C8C8 Content-Disposition: attachment; filename="smime.p7s" Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgEFADCABgkqhkiG9w0BBwEAAKCCA70w ggO5MIIDIqADAgECAhAaql39NsO1qLVjkS2hl517MA0GCSqGSIb3DQEBCwUAMGwxCzAJBgNVBAYT AlVTMRYwFAYDVQQIEw1NYXNzYWNodXNldHRzMS4wLAYDVQQKEyVNYXNzYWNodXNldHRzIEluc3Rp dHV0ZSBvZiBUZWNobm9sb2d5MRUwEwYDVQQLEwxDbGllbnQgQ0EgdjEwHhcNMjAwODAzMDEyNDIz WhcNMjEwODAxMDEyNDIzWjCBoTELMAkGA1UEBhMCVVMxFjAUBgNVBAgTDU1hc3NhY2h1c2V0dHMx LjAsBgNVBAoTJU1hc3NhY2h1c2V0dHMgSW5zdGl0dXRlIG9mIFRlY2hub2xvZ3kxFTATBgNVBAsT DENsaWVudCBDQSB2MTEVMBMGA1UEAxMMUWlhbnRhbiBIb25nMRwwGgYJKoZIhvcNAQkBFg1xaG9u Z0BNSVQuRURVMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAylUlEQdK4BSXKzoGh6As CKN/TpLmC0kjhPdxUKMj1/86Xl6GDCla4h95uISDOWVAKdu3cIlA8m9zRLT2jNEIkt1DVpXP6c9h y8RRyfJm0qlrvr6tsHi5AmO4Li6s2dEGaTxbakPL6vEn7ZYr86t5orq56nubki77Z8ZvRv9/fWdF bF/YBNGDayLNk0NbXIEQdCHiz1l+bxfw+GHHRmdOge3MKWSg463+GGMdxtLQ61AbtR2vm47FIJBt c0X6ptcInWUg4Nf/9vSNGl6KvREvfbEWKCT6TfL5ncIFlitf6ZWKue2PZ4ULFfIQ3/7EsEk03xxr S7sTOy7e2dbPboe/WwIDAQABo4GhMIGeMAkGA1UdEwQCMAAwEQYJYIZIAYb4QgEBBAQDAgWgMB0G A1UdJQQWMBQGCCsGAQUFBwMEBggrBgEFBQcDAjALBgNVHQ8EBAMCBeAwHQYDVR0OBBYEFDeb9Jlj XSm+y0CD872IhzRDIGv1MDMGA1UdHwQsMCowKKAmoCSGImh0dHA6Ly9jYS5taXQuZWR1L2NhL21p dGNsaWVudC5jcmwwDQYJKoZIhvcNAQELBQADgYEApBTx4tBbD5rQ+bNGd/Z3OBV07qFsm5QHNg0+ 6lxJ3j7q5zMMq35o6y5cBIhcFG6t+MFqJIdERZ3EprDturyqozQsIBMHFnqh+iZcMg0uQyssEqKZ hrzIdw8GuY4Z6jNewdGy5mwwG9yjpEbzWWgdofSM5rnezZz7EvCQu9ilt1sxggNDMIIDPwIBATCB gDBsMQswCQYDVQQGEwJVUzEWMBQGA1UECBMNTWFzc2FjaHVzZXR0czEuMCwGA1UEChMlTWFzc2Fj aHVzZXR0cyBJbnN0aXR1dGUgb2YgVGVjaG5vbG9neTEVMBMGA1UECxMMQ2xpZW50IENBIHYxAhAa ql39NsO1qLVjkS2hl517MA0GCWCGSAFlAwQCAQUAoIIBkzAYBgkqhkiG9w0BCQMxCwYJKoZIhvcN AQcBMBwGCSqGSIb3DQEJBTEPFw0yMDA5MzAxNzQ4MTNaMC8GCSqGSIb3DQEJBDEiBCAF79aM8AYw NKLfEzLa3q8vzcQbeDuhia2lNmrQkaa4ZjCBkQYJKwYBBAGCNxAEMYGDMIGAMGwxCzAJBgNVBAYT AlVTMRYwFAYDVQQIEw1NYXNzYWNodXNldHRzMS4wLAYDVQQKEyVNYXNzYWNodXNldHRzIEluc3Rp dHV0ZSBvZiBUZWNobm9sb2d5MRUwEwYDVQQLEwxDbGllbnQgQ0EgdjECEBqqXf02w7WotWORLaGX nXswgZMGCyqGSIb3DQEJEAILMYGDoIGAMGwxCzAJBgNVBAYTAlVTMRYwFAYDVQQIEw1NYXNzYWNo dXNldHRzMS4wLAYDVQQKEyVNYXNzYWNodXNldHRzIEluc3RpdHV0ZSBvZiBUZWNobm9sb2d5MRUw EwYDVQQLEwxDbGllbnQgQ0EgdjECEBqqXf02w7WotWORLaGXnXswDQYJKoZIhvcNAQEBBQAEggEA QYuJ9x3S1qloqWoguJynTZOJLpXj5r6LSBmQq17Qzi/nhVPHQ16gPtLKtRIwhc1JyRZsxFXrIAeZ FeRB9GXFKh/bT3sFWSF5Cc+rVFW13F3eJrEEItMgKawnrNXnQj9IPAIrdOG4OPu+kF3np+0ppshM 5FoDHW4R0qsYOBfqtnQ9vTmx23I7s99wEPPMdGaF5bDu9dW+XodgntECdbS+o3SJn7jsbDhDtgwG WODXSB6Tq4eOtAZVbJbO42NQyVfGL/oieXShosySwKx7KsmBuuTiZRpcxUP/AB4oQm0Z9i1YMRDV S8/9bAwr2/KncynUjXWIEgvy6vXyW/J7ta4ZiQAAAAAAAA== --Apple-Mail=_DB4A0434-406B-4009-904C-9E1FD049C8C8--