{"id":26315,"url":"https://patchwork.libcamera.org/api/1.1/patches/26315/?format=json","web_url":"https://patchwork.libcamera.org/patch/26315/","project":{"id":1,"url":"https://patchwork.libcamera.org/api/1.1/projects/1/?format=json","name":"libcamera","link_name":"libcamera","list_id":"libcamera_core","list_email":"libcamera-devel@lists.libcamera.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20260323102724.1385487-3-barnabas.pocze@ideasonboard.com>","date":"2026-03-23T10:27:19","name":"[RFC,v2,2/7] meson: Ignore `Wredundant-move` with GCC 11 and above","commit_ref":null,"pull_url":null,"state":"accepted","archived":false,"hash":"fb4e59fd8c6b3eb84e4dc8e41e0d95407afee876","submitter":{"id":216,"url":"https://patchwork.libcamera.org/api/1.1/people/216/?format=json","name":"Barnabás Pőcze","email":"barnabas.pocze@ideasonboard.com"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/26315/mbox/","series":[{"id":5837,"url":"https://patchwork.libcamera.org/api/1.1/series/5837/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=5837","date":"2026-03-23T10:27:17","name":"C++20 migration","version":2,"mbox":"https://patchwork.libcamera.org/series/5837/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/26315/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/26315/checks/","tags":{},"headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 32FC0C32F5\n\tfor ;\n\tMon, 23 Mar 2026 10:27:34 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 9C70862764;\n\tMon, 23 Mar 2026 11:27:30 +0100 (CET)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id C26D562737\n\tfor ;\n\tMon, 23 Mar 2026 11:27:27 +0100 (CET)","from pb-laptop.local (185.221.143.129.nat.pool.zt.hu\n\t[185.221.143.129])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 5BF37591;\n\tMon, 23 Mar 2026 11:26:11 +0100 (CET)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"I/krynXv\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1774261571;\n\tbh=87Zl8dAVhoX7TEAN+gzR8eiODF1j0cJrZ90GT79RjCc=;\n\th=From:To:Cc:Subject:Date:In-Reply-To:References:From;\n\tb=I/krynXvefRNBnQavvkr6G0UNOsIrpzFPek5IpIt33I3rCFOvY0k5uTz/IGye1a68\n\tuO53zy9lYf6ow4o8Ix+lR5+Cn5I4yEnNjDLvdY4cu2O/SfR7YsxGn48N0qy59Xb7pq\n\tnGW+cMxz1dU+GFuoPB+/zOEiJskh4Ek+pr2tQai8=","From":"=?utf-8?q?Barnab=C3=A1s_P=C5=91cze?= ","To":"libcamera-devel@lists.libcamera.org","Cc":"Laurent Pinchart ","Subject":"[RFC PATCH v2 2/7] meson: Ignore `Wredundant-move` with GCC 11 and\n\tabove","Date":"Mon, 23 Mar 2026 11:27:19 +0100","Message-ID":"<20260323102724.1385487-3-barnabas.pocze@ideasonboard.com>","X-Mailer":"git-send-email 2.53.0","In-Reply-To":"<20260323102724.1385487-1-barnabas.pocze@ideasonboard.com>","References":"<20260323102724.1385487-1-barnabas.pocze@ideasonboard.com>","MIME-Version":"1.0","Content-Type":"text/plain; charset=UTF-8","Content-Transfer-Encoding":"8bit","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "},"content":"In C++20 mode, object slicing in a return statement triggers automatic move\nsince GCC 11, and using `std::move()` emits `-Wredundant-move` in those\nsame GCC versions. So disable the warning in those as well.\n\nThis is relevant for `valueOrTuple()` in `py_helpers.cpp`, which\nreturns a `py::tuple` as `py::object`.\n\nSigned-off-by: Barnabás Pőcze \nReviewed-by: Laurent Pinchart \n---\n meson.build | 21 +++++++++++----------\n 1 file changed, 11 insertions(+), 10 deletions(-)","diff":"diff --git a/meson.build b/meson.build\nindex 82867f82b..fa38fa2c0 100644\n--- a/meson.build\n+++ b/meson.build\n@@ -159,16 +159,17 @@ if cc.get_id() == 'gcc'\n error('gcc version is too old, libcamera requires 9.0 or newer')\n endif\n \n- # gcc 13 implements the C++23 version of automatic move from local\n- # variables in return statements (see\n- # https://en.cppreference.com/w/cpp/language/return). As a result, some\n- # previously required explicit std::move() in return statements generate\n- # warnings. Those moves can't be removed as older compiler versions could\n- # use copy constructors instead of move constructors. The easiest fix is to\n- # disable the warning. With -Wpessimizing-move enabled, the compiler will\n- # still warn of pessimizing moves, only the redundant but not pessimizing\n- # moves will be ignored.\n- if cc.version().version_compare('>=13')\n+ # In C++20 mode, prior to gcc 11, object slicing in a return statement didn't\n+ # perform automatic move. It required explicit std::move() usage, which now\n+ # generate warnings. Those moves can't be removed as older compiler versions\n+ # could use copy constructors instead of move constructors. The easiest fix\n+ # is to disable the warning. With -Wpessimizing-move enabled, the compiler\n+ # will still warn of pessimizing moves, only the redundant but not\n+ # pessimizing moves will be ignored.\n+ #\n+ # \\todo When dropping support for compilers older than gcc 11, drop the\n+ # argument and remove the unneeded std::move() calls.\n+ if cc.version().version_compare('>=11')\n cpp_arguments += [\n '-Wno-redundant-move',\n ]\n","prefixes":["RFC","v2","2/7"]}