From patchwork Fri Mar 14 00:20:51 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Elijah Newren X-Patchwork-Id: 14016103 Received: from mail-wr1-f45.google.com (mail-wr1-f45.google.com [209.85.221.45]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 862A6645 for ; Fri, 14 Mar 2025 00:20:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.45 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741911660; cv=none; b=E7DKk9bHpWSGSf4XQZ5YaD9MAJzEkwlQTvv81L9H5aA/pIb3YrOzFovL6bXSlYsmfGwXj0+lLsd2dAEwQZlAh8gnIlBmH7T4HoNgXG/K7OzdOj8asrEOzhFkL0mVp54Td/YrdkLGfIgebaIKYO/0GO+q/fCUmJQSuW4ZcR/qAAk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741911660; c=relaxed/simple; bh=mRgayroK1BcvKQ1Rwkhhb2r2ZaNecThni6T14iI6YB0=; h=Message-Id:In-Reply-To:References:From:Date:Subject:Content-Type: MIME-Version:To:Cc; b=nrLaBaBbM316J8wh06w04nEx0aHfdJJWKxdV+ZQvSYM2V/KY+E2Fl80rL8B+BRZjQylGRSsr+pRD6aHJWUqHVeHdjd420vM/i2RbqNtApoThD6iDL4OQOLgYEPai/ntadea69nu5B/Jlpyun07O5PVecgefTw1P/MG6/8uTC5x8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=agY239zb; arc=none smtp.client-ip=209.85.221.45 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="agY239zb" Received: by mail-wr1-f45.google.com with SMTP id ffacd0b85a97d-3913fdd003bso843105f8f.1 for ; Thu, 13 Mar 2025 17:20:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1741911656; x=1742516456; darn=vger.kernel.org; h=cc:to:mime-version:content-transfer-encoding:fcc:subject:date:from :references:in-reply-to:message-id:from:to:cc:subject:date :message-id:reply-to; bh=b18BZcSRc2K7cJv/D+oSBt1xsZUSo9cA8FGp4u8zQRI=; b=agY239zbjajhTmXIxjRrVtzKjjS4/Nl9Wj72ICTTWJAy6vk8/ngLtUDZrWFijZIZvV 4uuNLBaNosSZ6DCS+WFDZJ1t0f8l5DNpl4ZzQ/M5giBnZK4w6q10LvVaON6+tCuYCRhc 0QB6AXL9pgY812i1U5B79V2Mk64h6bgXu3/4tsVVcDJ7FzSqs4ydmAURIxXv2+mVL+F0 tX7XuAj6os9EmGouIe6F2gvPhSLrjkvUY3dFaRPP4MponDltYtW3spQ2g5gZITLfP4OF 8Zv1GsnJokj/ZfyBZthrXbJMh2pZUIytFcj/XnJ8dQwVzuxXP0wJSfiDkfzY2pLCYUJM A0jA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1741911656; x=1742516456; h=cc:to:mime-version:content-transfer-encoding:fcc:subject:date:from :references:in-reply-to:message-id:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=b18BZcSRc2K7cJv/D+oSBt1xsZUSo9cA8FGp4u8zQRI=; b=I896cL0okOC8qPe/oXDip0wzqZbCOvEUsw3cnCOS9TtRVEZAM3ovavgc5vIKjHOzJl /sgtxMVtWgXrRmNX5v+EHzgCMEwkV8NBGay5dffsv91269Ql1ZAKBglI4yZWIPpCvp+t vcfFShjVw+SjWFEUillxO7+Kk+TBxR3/OX+8k/ML8PJ/qcYkAKu3mC4MMpplPeYI0wPS vA7i7ybI2ZOBYWVug6uDQzEWqfTN7hWJMFb2TEvcWieVVz/c5SB0pLxv7r+VlbyukJ18 0shbYzDU6aWcARmwkrOauH80Kpx8pQjVMSUBd6Od+uGyxlpd6NnqwxP9+nNKMT+Y01lA ERpA== X-Gm-Message-State: AOJu0YxVhzHAS3L5A3xyQf6XtIO6m5Dg97i8GyII3EBpOAvgay3mi3QW VKIc9D39tc77MN0rh7y8XpC47DvR91Vttvovi588qLedNN0iuk0xOuAhsQ== X-Gm-Gg: ASbGncvSp50E+BNTAnRby1t+YPQ02lNjSkc9frC48cKCoXqWg9gb+VJqs+oqSuQYrxp ev9sGtYlH5XJlSbJT0y1mw72FFdmplA3OoqpX5j6UnNC6p13MbnTMNfin+SqStDrQ8m2DUhcVCl UHYt3PGOzeLe7b3IzeS+pYd/xxDe/IeOuOzTa+8PvdSFdg81WNXjbwZvVAnxPdXv+X9ew/Cg4aL 1ZAzm2PZLgOH7ToVjzBKMge8cot1ahagnIRQHlhMOBme+PbsqRyktAPzU33CtwQVIkldvFy4ot6 VU2Pnuo4kev6vpcZorZ7ZpwGxk0X2TrSPSRPebZbi8vQUQ== X-Google-Smtp-Source: AGHT+IETWu3r7f8/skQpVXs1kPJifZaYtDpJh2fnYrj875Ji6kEyLEBToujmhHEJfeE4wdi0Kx4oWg== X-Received: by 2002:a05:6000:1447:b0:391:65c:1b05 with SMTP id ffacd0b85a97d-3971bfce005mr519747f8f.11.1741911656384; Thu, 13 Mar 2025 17:20:56 -0700 (PDT) Received: from [127.0.0.1] ([13.74.141.28]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-395c83b6a10sm3706888f8f.36.2025.03.13.17.20.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 13 Mar 2025 17:20:54 -0700 (PDT) Message-Id: <80dcc2ba3aa0ef72abe18f8525d571ea39ac6382.1741911652.git.gitgitgadget@gmail.com> In-Reply-To: References: Date: Fri, 14 Mar 2025 00:20:51 +0000 Subject: [PATCH 2/3] ci: add build checking for side-effects in assert() calls Fcc: Sent Precedence: bulk X-Mailing-List: git@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 To: git@vger.kernel.org Cc: Elijah Newren , Elijah Newren From: Elijah Newren From: Elijah Newren It is a big no-no to have side-effects in an assertion, because if the assert() is compiled out, you don't get that side-effect, leading to the code behaving differently. That can be a large headache to debug. We have roughly 566 assert() calls in our codebase (my grep might have picked up things that aren't actually assert() calls, but most appeared to be). All but 9 of them can be determined by gcc to be free of side effects with a clever redefine of assert(). The current 9 appear to be free of side effects to me as well, but are too complicated for a compiler/linker to figure that since each assertion involves some kind of function call. Add a CI job which will find and report these possibly problematic assertions, and have the job suggest to the user that they replace these with BUG_IF_NOT() calls. Example output from running: ``` ERROR: The compiler could not verify the following assert() calls are free of side-effects. Please replace with BUG_IF_NOT() calls. /home/newren/floss/git/diffcore-rename.c:1409 assert(!dir_rename_count || strmap_empty(dir_rename_count)); /home/newren/floss/git/merge-ort.c:1645 assert(renames->deferred[side].trivial_merges_okay && !strset_contains(&renames->deferred[side].target_dirs, path)); /home/newren/floss/git/merge-ort.c:794 assert(omittable_hint == (!starts_with(type_short_descriptions[type], "CONFLICT") && !starts_with(type_short_descriptions[type], "ERROR")) || type == CONFLICT_DIR_RENAME_SUGGESTED); /home/newren/floss/git/merge-recursive.c:1200 assert(!merge_remote_util(commit)); /home/newren/floss/git/object-file.c:2709 assert(would_convert_to_git_filter_fd(istate, path)); /home/newren/floss/git/parallel-checkout.c:280 assert(is_eligible_for_parallel_checkout(pc_item->ce, &pc_item->ca)); /home/newren/floss/git/scalar.c:244 assert(have_fsmonitor_support()); /home/newren/floss/git/scalar.c:254 assert(have_fsmonitor_support()); /home/newren/floss/git/sequencer.c:4968 assert(!(opts->signoff || opts->no_commit || opts->record_origin || should_edit(opts) || opts->committer_date_is_author_date || opts->ignore_date)); ``` Note that if there are possibly problematic assertions, not necessarily all of them will be shown in a single run, because the compiler errors may include something like "ld: ... more undefined references to `not_supposed_to_survive' follow" instead of listing each individually. But in such cases, once you clean up a few that are shown in your first run, subsequent runs will show (some of) the ones that remain, allowing you to iteratively remove them all. Signed-off-by: Elijah Newren --- Makefile | 4 ++++ ci/check-unsafe-assertions.sh | 18 ++++++++++++++++++ ci/run-static-analysis.sh | 2 ++ git-compat-util.h | 6 ++++++ 4 files changed, 30 insertions(+) create mode 100755 ci/check-unsafe-assertions.sh diff --git a/Makefile b/Makefile index 7315507381e..57774912f18 100644 --- a/Makefile +++ b/Makefile @@ -2261,6 +2261,10 @@ ifdef WITH_BREAKING_CHANGES BASIC_CFLAGS += -DWITH_BREAKING_CHANGES endif +ifdef CHECK_ASSERTION_SIDE_EFFECTS + BASIC_CFLAGS += -DCHECK_ASSERTION_SIDE_EFFECTS +endif + ifdef INCLUDE_LIBGIT_RS # Enable symbol hiding in contrib/libgit-sys/libgitpub.a without making # us rebuild the whole tree every time we run a Rust build. diff --git a/ci/check-unsafe-assertions.sh b/ci/check-unsafe-assertions.sh new file mode 100755 index 00000000000..d66091efd22 --- /dev/null +++ b/ci/check-unsafe-assertions.sh @@ -0,0 +1,18 @@ +#!/bin/sh + +make CHECK_ASSERTION_SIDE_EFFECTS=1 >compiler_output 2>compiler_error +if test $? != 0 +then + echo "ERROR: The compiler could not verify the following assert()" >&2 + echo " calls are free of side-effects. Please replace with" >&2 + echo " BUG_IF_NOT() calls." >&2 + grep undefined.reference.to..not_supposed_to_survive compiler_error \ + | sed -e s/:[^:]*$// | sort | uniq | tr ':' ' ' \ + | while read f l + do + printf "${f}:${l}\n " + awk -v start="$l" 'NR >= start { print; if (/\);/) exit }' $f + done + exit 1 +fi +rm compiler_output compiler_error diff --git a/ci/run-static-analysis.sh b/ci/run-static-analysis.sh index 0d51e5ce0e7..ae714e020ae 100755 --- a/ci/run-static-analysis.sh +++ b/ci/run-static-analysis.sh @@ -31,4 +31,6 @@ exit 1 make check-pot +${0%/*}/check-unsafe-assertions.sh + save_good_tree diff --git a/git-compat-util.h b/git-compat-util.h index c3415ad7e0a..0aefd763751 100644 --- a/git-compat-util.h +++ b/git-compat-util.h @@ -1584,4 +1584,10 @@ static inline void *container_of_or_null_offset(void *ptr, size_t offset) ((uintptr_t)&(ptr)->member - (uintptr_t)(ptr)) #endif /* !__GNUC__ */ +#ifdef CHECK_ASSERTION_SIDE_EFFECTS +#undef assert +extern int not_supposed_to_survive; +#define assert(expr) ((void)(not_supposed_to_survive || (expr))) +#endif /* CHECK_ASSERTION_SIDE_EFFECTS */ + #endif