From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.bugs Subject: bug#62958: [PATCH] Set PAGER=cat in comint.el Date: Tue, 09 May 2023 19:43:03 +0300 Message-ID: <83wn1ha220.fsf@gnu.org> References: <83edof6oln.fsf@gnu.org> <83zg724kea.fsf@gnu.org> <835y97jnfd.fsf@gnu.org> <83pm7aay70.fsf@gnu.org> <874jol1rml.fsf@catern.com> <831qjpbj8j.fsf@gnu.org> Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="28958"; mail-complaints-to="usenet@ciao.gmane.io" Cc: sbaugh@catern.com, 62958@debbugs.gnu.org To: Spencer Baugh Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Tue May 09 18:43:16 2023 Return-path: Envelope-to: geb-bug-gnu-emacs@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 1pwQQm-0007Nq-4G for geb-bug-gnu-emacs@m.gmane-mx.org; Tue, 09 May 2023 18:43:16 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pwQQa-0002gF-Ay; Tue, 09 May 2023 12:43:04 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pwQQY-0002ag-S2 for bug-gnu-emacs@gnu.org; Tue, 09 May 2023 12:43:02 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1pwQQY-0001I3-Jp for bug-gnu-emacs@gnu.org; Tue, 09 May 2023 12:43:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1pwQQY-0006wX-FB for bug-gnu-emacs@gnu.org; Tue, 09 May 2023 12:43:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Tue, 09 May 2023 16:43:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 62958 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: patch Original-Received: via spool by 62958-submit@debbugs.gnu.org id=B62958.168365053026616 (code B ref 62958); Tue, 09 May 2023 16:43:02 +0000 Original-Received: (at 62958) by debbugs.gnu.org; 9 May 2023 16:42:10 +0000 Original-Received: from localhost ([127.0.0.1]:44279 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1pwQPi-0006vD-5G for submit@debbugs.gnu.org; Tue, 09 May 2023 12:42:10 -0400 Original-Received: from eggs.gnu.org ([209.51.188.92]:39308) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1pwQPe-0006ug-QD for 62958@debbugs.gnu.org; Tue, 09 May 2023 12:42:08 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pwQPZ-0001Ap-91; Tue, 09 May 2023 12:42:01 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=References:Subject:In-Reply-To:To:From:Date: mime-version; bh=DkO2I/FSp3LVbOgndWYgkRX9xwT8die6w3FVXCKsuuE=; b=Jx6SIg3s3CqF CPUhh0yGiA+MzB86R67ArqKKkGSl8RFogcxyWLVr+JXJ6/x98WI4AoRmHoPHB5+28kImOTfN6mIWT 3QmXHT5T0ShD6xbKK8iTwR/I9nTY5WMBJNly+UFHH+WLWUHR5B3876vbhrxWn8c1xUVUMGLJI9eMw 7NSQt3D5xAuY/lJPal7WHrcDduMmr2AAl7gHmthqy1eNFbOOZOhDdto9rCsJ0yTWiec0+Jv+UywzU YI0xrhTS1f4XFSE+vytqv/3CjLp6MszAEOSE0+YyvtuAVvWc9mgBinPSABJjXLGqc+3I4yWgROkCZ Y7lOoc4Xn2JLh0jHGVTuBA==; Original-Received: from [87.69.77.57] (helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pwQPY-0002PE-Ot; Tue, 09 May 2023 12:42:01 -0400 In-Reply-To: (message from Spencer Baugh on Tue, 09 May 2023 12:30:42 -0400) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list 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-mx.org@gnu.org Original-Sender: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.bugs:261429 Archived-At: > From: Spencer Baugh > Cc: sbaugh@catern.com, 62958@debbugs.gnu.org > Date: Tue, 09 May 2023 12:30:42 -0400 > > Eli Zaretskii writes: > > >> From: sbaugh@catern.com > >> Date: Tue, 09 May 2023 14:55:31 +0000 (UTC) > >> Cc: Spencer Baugh , 62958@debbugs.gnu.org > >> > >> Eli Zaretskii writes: > >> > >> >> From: Spencer Baugh > >> >> Cc: 62958@debbugs.gnu.org > >> >> Date: Mon, 08 May 2023 15:38:12 -0400 > >> >> > >> >> > Pagination is not needed, and gets in the way, when the output of > >> >> > the program is directed to an Emacs buffer, so in those cases > >> >> > pagination should be disabled. To disable pagination, this > >> >> > variable's value should be a string that names a program, such > >> >> > as \"cat\", which passes through all of the output without any > >> >> > filtering or delays. Comint will then set the PAGER variable > >> >> > to name that program, when it invokes external programs." > >> >> > >> >> I think it's worth noting the fact that there are programs which depend > >> >> on pagination for their normal functionality. How about this short > >> >> additional paragraph added after your text: > >> >> > >> >> "Disabling pagination means programs will produce their entire output > >> >> immediately. If only part of the output is useful, this can be > >> >> wasteful. For some programs, this can be avoided by using commands (for > >> >> example, `vc-print-log') which run the program, limit the output it > >> >> produces, and let the user interactively browse the output inside > >> >> Emacs." > >> > > >> > Sorry, I don't understand: why would it matter that a program produces > >> > its output immediately when that output is redirected to an Emacs > >> > buffer? Whatever the amount of output, the user can always page > >> > through it interactively and conveniently using the normal movement > >> > commands, no? What am I missing? > >> > >> If the command produces a lot of output it can take a long time to run > >> and slow down Emacs. > >> > >> For example, if a user disables pagination, runs M-x shell, and then > >> runs "git log" in the Emacs repo, it takes ~3.5 minutes to run and > >> produces ~1.5 million lines. Even if all they want is to see the 10 > >> most recent commits. There are several negative effects of this, in > >> decreasing order of importance: > >> > >> - The shell buffer now has way more output, which slows down navigation > >> and operations on that buffer forever after, including font lock. > >> - The user's shell is blocked during that whole time, preventing further > >> shell commands. > >> - git log producing unnecessary output wastes CPU and IO. > >> > >> If "git log" is run with a pager, it can complete as soon as the user > >> exits the pager, and it only produces a few lines. > > > > But this is impossible in general, AFAIU: most comint clients aren't > > prepared for interactive paging anyway. If someone wants paging, they > > should use "M-x term" or "M-x ansi-term", the terminal emulators that > > Emacs provides. > > Yes. I of course know that, that's why I filed this bug :) > > Nevertheless, today by default many programs run in comint clients will > run a pager, and even though it is a hassle and gets in the way inside > Emacs, it does prevent some programs from producing lots of output and > yielding the negative effects I mentioned previously: > > >> - The shell buffer now has way more output, which slows down navigation > >> and operations on that buffer forever after, including font lock. > >> - The user's shell is blocked during that whole time, preventing further > >> shell commands. > >> - git log producing unnecessary output wastes CPU and IO. > > Because of these negative effects which will start happening for some > programs when the user disables pagination, I think it's important for > users to know that there's alternatives for such programs: namely, using > native Emacs interfaces like vc-print-log. OK, but what's the purpose of the addition you were proposing? It basically says that sometimes paging should not be disabled, but since this is a defcustom, and the default is not to disable paging, that already speaks volumes about the same issue, right?