From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Michael Heerdegen Newsgroups: gmane.emacs.bugs Subject: bug#37888: 27.0.50; Streams and errors in element generation Date: Wed, 23 Oct 2019 16:27:36 +0200 Message-ID: <87eez3eduv.fsf@web.de> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="75920"; mail-complaints-to="usenet@blaine.gmane.org" Cc: Nicolas Petton To: 37888@debbugs.gnu.org Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Wed Oct 23 16:29:45 2019 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([209.51.188.17]) by blaine.gmane.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1iNHdv-000JcK-Sp for geb-bug-gnu-emacs@m.gmane.org; Wed, 23 Oct 2019 16:29:44 +0200 Original-Received: from localhost ([::1]:37666 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iNHdt-0005zH-VO for geb-bug-gnu-emacs@m.gmane.org; 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Wed, 23 Oct 2019 10:27:42 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=web.de; s=dbaedf251592; t=1571840849; bh=htsDzSkcSh7PJHJ26JaqqQB9XgJtSfNKt2IkVOdddcs=; h=X-UI-Sender-Class:From:To:Cc:Subject:Date; b=UUQOU7n1Vz3jzWhW19sIi59fdEDOXizLLMJfVBo3NplSD/6bp5nzsAYQisJo3lnxD kMflt5i7vZeSJMaqaYJ3sB3GsrQHLj+qaSqBh/+UMM+NDUDCIWENSFho+cvQrV/YK8 sviVhzMsuOeDnHayYPWtjKIFXWtFCTqB2Pw+rg84= X-UI-Sender-Class: c548c8c5-30a9-4db5-a2e7-cb6cb037b8f9 Original-Received: from drachen.dragon ([94.218.222.9]) by smtp.web.de (mrweb103 [213.165.67.124]) with ESMTPSA (Nemesis) id 0MOArg-1iK0Ll0Na0-005a1M; Wed, 23 Oct 2019 16:27:29 +0200 X-Provags-ID: V03:K1:3WlQSIN+gI6BmtDSAJ639Ktbiy68/HCE+Nqmg3e62HdPE8qlPY1 B2rbq0ZJZ0tgdusm5Zxp0gyx5Gi7l9EXPpDpFGtyaMqsA33uKe9/JbtWdlGvWyChU9+3IY0 NMb5aulmvL+16Cngels+xTWXfR1ZrGreWX/r/VCiiitAxiCFVtioiYqKX1AheRHyKAg7P1s YHikGfVXiKbei5gJKz78A== X-UI-Out-Filterresults: notjunk:1;V03:K0:Judw5nd+vyU=:rfVefyP2bnq+PX1cmz1lE0 0Ns1ygeHr8wjxVnJmm3p+5CrqIhnRWy+3IsBlKiR/crHi5hA+3ak089t9TXvSwKR+wk61yL9N /ZJ7EBQTvWPpxRFab+0HPZuEsblKsaXiOHEpwbGPb51kljcTm6xr+3WvWNgT6C4MI4xUfIs/H LXXmThQUdvMu0MM4N48JINb2PW6p9pwS19IBsbzy12sKY6WvhcRaBx4j7C3Ri9BLApqq4kb7C AWu2LhmraYTLPlcnG8E5cm23Y1QyZR0fd15A3X35xA/IZexpb6jrJ8FpD/62LD7c9nDDqEcvA tv72gG5T/o2qsr0hQmDNCn0m5rl5wqvyJ8ZhoDW2hVJ1/vW0MfdVvRCGjELGRN+ak1U3y7emL O9Of09K/cKd1/Ur+t59VCaAHhs7pG/1GYmXJ9O0XAbNXALBnA0ZUeAnHpmrmV3Nfguge4nNNG JFzTAVen+eRCsQKyxeW5vFZQzM5WVm4jZOjIoDsIenyNZpchigk6QDyMgEpurCplK7rzr6/7v zVt3Ho9b3MCsAZr3pkuk4cMNqn+/MJi2QCMZpV+fzrKDsaV4qJ7fB5mxoEAkicqjRJsZ3kd7e YpWVW7JawVwSrAtTmLtESle5kz+UPb0XTlUSEIYHkYo4mrzZmAO6T6Y0EHbi7CyZu4k4rFTaF rIevrILxsqNNsmhd9opntt0HTHn3o1h27G7L6BMH2dCjBLsXhyieXnjmrdM88xoTIGv9HjNeH +02MFjXz55lb8FNPa/ulvivZplwcilWBW9zvUVy2IMT9db8eRFiaUumd5JoDrng5KySvXxCZ X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.51.188.43 X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.org gmane.emacs.bugs:170068 Archived-At: Hi, consider this case (it appeared to me in real life): --8<---------------cut here---------------start------------->8--- (defun test-stream (n) (stream-cons n (if (< n 0) (error "test") (test-stream (1- n))))) (setq my-stream (test-stream 10)) (condition-case nil (seq-length my-stream) (error (message "Hmm, didn't work so well"))) --8<---------------cut here---------------end--------------->8--- Now, what happened to `my-stream' after evaluating this? If you try to use it, you get a quite confusing error: (seq-length my-stream) |-- stream--force: Wrong type argument: streamp, (((n . -1) t) nil ...) i.e. the stream is broken. I wonder if we could improve this case. I'm not sure how, however. Should referencing the element whose generation caused the error raise the same error again, or a standardized kind of error? Should the whole stream be invalidated in some way? FWIW, in my use case I expected the stream to raise the same error again. Would it be reasonable to make the stream just retry to calculate the problematic element? TIA, Michael. In GNU Emacs 27.0.50 (build 27, x86_64-pc-linux-gnu, GTK+ Version 3.24.12) of 2019-10-23 built on drachen Repository revision: 39ba44f18445c7759de5ac91ce25e53123c2abeb Repository branch: master Windowing system distributor 'The X.Org Foundation', version 11.0.12004000 System Description: Debian GNU/Linux bullseye/sid