From debbugs-submit-bounces@debbugs.gnu.org Wed Jan 06 04:56:36 2021 Received: (at 45570) by debbugs.gnu.org; 6 Jan 2021 09:56:36 +0000 Received: from localhost ([127.0.0.1]:43465 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1kx5YS-00022F-1D for submit@debbugs.gnu.org; Wed, 06 Jan 2021 04:56:36 -0500 Received: from eggs.gnu.org ([209.51.188.92]:56174) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1kx5YQ-00021z-0P for 45570@debbugs.gnu.org; Wed, 06 Jan 2021 04:56:34 -0500 Received: from fencepost.gnu.org ([2001:470:142:3::e]:57354) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kx5YH-0008TB-PY; Wed, 06 Jan 2021 04:56:26 -0500 Received: from [2a01:e0a:1d:7270:af76:b9b:ca24:c465] (port=41410 helo=ribbon) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1kx5YH-0002rt-79; Wed, 06 Jan 2021 04:56:25 -0500 From: =?utf-8?Q?Ludovic_Court=C3=A8s?= To: Leo Prikler Subject: Re: bug#45570: [PATCH] system: Assert, that user and group names are unique. References: <20210102055728.22594-1-leo.prikler@student.tugraz.at> X-URL: http://www.fdn.fr/~lcourtes/ X-Revolutionary-Date: 17 =?utf-8?Q?Niv=C3=B4se?= an 229 de la =?utf-8?Q?R?= =?utf-8?Q?=C3=A9volution?= X-PGP-Key-ID: 0x090B11993D9AEBB5 X-PGP-Key: http://www.fdn.fr/~lcourtes/ludovic.asc X-PGP-Fingerprint: 3CE4 6455 8A84 FDC6 9DB4 0CFB 090B 1199 3D9A EBB5 X-OS: x86_64-pc-linux-gnu Date: Wed, 06 Jan 2021 10:56:23 +0100 In-Reply-To: <20210102055728.22594-1-leo.prikler@student.tugraz.at> (Leo Prikler's message of "Sat, 2 Jan 2021 06:57:29 +0100") Message-ID: <87v9cao0c8.fsf@gnu.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Spam-Score: -2.3 (--) X-Debbugs-Envelope-To: 45570 Cc: 45570@debbugs.gnu.org, conjaroy@gmail.com X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -3.3 (---) Hi, Leo Prikler skribis: > *gnu/system/shadow.scm (find-duplicates): New variable. > (assert-unique-account-names, assert-unique-group-names): New variables. > (account-activation): Use them here. [...] > +(define (find-duplicates list =3D) > + (match list > + ('() '()) This should be: (match list (() '()) =E2=80=A6) I=E2=80=99m surprised '() works as a pattern. > + ((first . rest) > + (if (member first rest =3D) ; (srfi srfi-1) member > + (cons first (find-duplicates rest =3D)) > + (find-duplicates rest =3D))))) Note that this is quadratic; it=E2=80=99s fine as long as we don=E2=80=99t = have =E2=80=9Ctoo many=E2=80=9D users, which may be the case in general. > +(define (assert-unique-account-names users) > + (for-each > + (lambda (account) > + (raise (condition > + (&message > + (message > + (format #f (G_ "account with name '~a' found twice.") > + (user-account-name account))))))) > + (find-duplicates users (lambda (alice bob) > + (string=3D? (user-account-name alice) > + (user-account-name bob)))))) =E2=80=98for-each=E2=80=99 looks awkward since we=E2=80=99ll stop on the fi= rst one. How about something like: (define (assert-unique-account-names users) (match (find-duplicates things =E2=80=A6) (() #t) (lst (raise (formatted-message (G_ "the following accounts appear more th= an once:~{ ~a~}~%" lst)))))) ? Thanks! Ludo=E2=80=99.