Question

我有一个C ++项目，我想在其中使用-Wsign-conversion编译选项。使用构建工具Bazel 0.26.0。我的自行编写的代码不会生成该类型的警告。该项目使用Googletest。不幸的是，Googletest会生成这种警告，这破坏了我的构建。这是我的文件：

.bazelrc

build --cxxopt=-Werror           # Every warning is treated as an error.
build --cxxopt=-std=c++14
build --cxxopt=-Wsign-conversion # Warn for implicit conversions that may change the sign of an integer value

gtest.BUILD

cc_library(
    name = "main",
    srcs = glob(
        ["src/*.cc"],
        exclude = ["src/gtest-all.cc"]
    ),
    hdrs = glob([
        "include/**/*.h",
        "src/*.h"
    ]),
    copts = ["-Iexternal/gtest/include"],
    linkopts = ["-pthread"],
    visibility = ["//visibility:public"],
)

工作空间

workspace(name = "GTestDemo")

load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")

git_repository(
    name = "googletest",
    remote = "https://github.com/google/googletest",
    #tag = "release-1.8.1",
    commit = "2fe3bd994b3189899d93f1d5a881e725e046fdc2", 
    shallow_since = "1535728917 -0400",
)

已构建

cc_test(
    name = "tests",
    srcs = ["test.cpp"],
    copts = ["-Iexternal/gtest/include"],
    deps = [
            "@googletest//:gtest_main",
        ],
)

test.cpp

#include <iostream>

#include "gtest/gtest.h"

TEST(sample_test_case, sample_test)
{
    EXPECT_EQ(1, 1);
}

当我尝试构建代码时，显示以下错误：

Starting local Bazel server and connecting to it...
INFO: Analyzed target //:tests (21 packages loaded, 540 targets configured).
INFO: Found 1 target...
INFO: Deleting stale sandbox base /mnt/ramdisk/bazel-sandbox.be60b2910864108c1e29c6fce8ad6ea4
ERROR: /home/admin/.cache/bazel/_bazel_admin/cc9b56275ffa85d1a0fca263d1d708e4/external/googletest/BUILD.bazel:55:1: C++ compilation of rule '@googletest//:gtest' failed (Exit 1) gcc failed: error executing command /usr/bin/gcc -U_FORTIFY_SOURCE -fstack-protector -Wall -Wunused-but-set-parameter -Wno-free-nonheap-object -fno-omit-frame-pointer '-std=c++0x' -MD -MF ... (remaining 36 argument(s) skipped)

Use --sandbox_debug to see verbose messages from the sandbox
external/googletest/googletest/src/gtest-filepath.cc: In member function 'testing::internal::FilePath testing::internal::FilePath::RemoveFileName() const':
external/googletest/googletest/src/gtest-filepath.cc:168:45: error: conversion to 'std::__cxx11::basic_string<char>::size_type {aka long unsigned int}' from 'long int' may change the sign of the result [-Werror=sign-conversion]
     dir = std::string(c_str(), last_sep + 1 - c_str());
                                ~~~~~~~~~~~~~^~~~~~~~~
cc1plus: all warnings being treated as errors
Target //:tests failed to build
Use --verbose_failures to see the command lines of failed build steps.
INFO: Elapsed time: 7.225s, Critical Path: 0.66s
INFO: 0 processes.
FAILED: Build did NOT complete successfully

Bazel是否有可能忽略googletest等第三方库中的警告？

Answer 1

这更多是GCC问题。

“系统标题” are immune from this kind of thing：

-Wsystem-headers ：为在系统头文件中找到的结构打印警告消息。 通常会抑制系统标头中的警告，因为它们通常并不表示真正的问题，只会使编译器的输出难以阅读。

因此，您可以使用GCC's -isystem flag（而不是-I）假装第三方库是系统头文件：

copts = ["-isystem external/gtest/include"],

Answer 2

Bazel的--per_file_copt允许为所有匹配某些正则表达式的文件设置标志。 .bazelrc中的类似内容应该可以满足您的需求：

# Warn for implicit conversions that may change the sign of an integer value,
# for C++ files not in googletest
build --per_file_copt=.*\.(cc|cpp),-googletest/.*@-Wsign-conversion

您需要更新它以匹配用于.cc和.cpp以外的C ++文件的所有扩展名。 cc_library.srcs的文档列出了Bazel使用的所有扩展，以供参考。

我不知道如何在标记中匹配@googletest//，因为我看不到有逃脱@的方法...但是，我很确定它是否匹配针对@googletest而非external/googletest之类的东西，因为/googletest与任何内容都不匹配。可能无关紧要，但是如果其中包含googletest的任何其他文件名，则要记住这一点。

将警告视为错误，但忽略googletest中的警告

2 个答案: