Jsoncpp cmake 在 TravisCI 中执行 github 时抛出被视为错误的警告

Question

我的存储库中有一个 .travis.yml 文件（每当我推送到 github 时它总是运行），看起来像这样：

---
language: java
sudo: true
jdk: oraclejdk8
addons:
  apt:
    sources:
      - ubuntu-toolchain-r-test
      - llvm-toolchain-precise-3.5
      - george-edison55-precise-backports # cmake 3.2.3 / doxygen 1.8.3
    packages:
      - cmake
      - cmake-data
      - gcc-4.9
      - g++-4.9
      - clang-3.5
      - valgrind
before_install:
  - sudo apt-get -qq update
  - git clone https://github.com/open-source-parsers/jsoncpp.git
  - cd jsoncpp
  - python amalgamate.py
  - mkdir build
  - cd build
  - cmake ..
  - make
script:
  - cd ../..
  - mvn install -Dlog4j.configurationFile="src/test/resources/log4j.xml"

yaml 运行一直完美到 make 语句，它记录了以下消息：

$ make
Scanning dependencies of target jsoncpp_lib_static
[ 16%] Building CXX object src/lib_json/CMakeFiles/jsoncpp_lib_static.dir/json_reader.cpp.o
[ 33%] Building CXX object src/lib_json/CMakeFiles/jsoncpp_lib_static.dir/json_value.cpp.o
/home/travis/build/fire-d/testDemo/jsoncpp/src/lib_json/json_value.cpp: In copy constructor ‘Json::Value::CZString::CZString(const Json::Value::CZString&)’:
/home/travis/build/fire-d/testDemo/jsoncpp/src/lib_json/json_value.cpp:273:78: error: conversion to ‘unsigned char:2’ from ‘unsigned int’ may alter its value [-Werror=conversion]
cc1plus: some warnings being treated as errors
make[2]: *** [src/lib_json/CMakeFiles/jsoncpp_lib_static.dir/json_value.cpp.o] Error 1
make[1]: *** [src/lib_json/CMakeFiles/jsoncpp_lib_static.dir/all] Error 2
make: *** [all] Error 2
The command "make" failed and exited with 2 during .

显然，构建失败是因为 CMAKE_CXX_FLAGS 在包含文件 json_value.cpp.o。由于脚本总是运行s 远程，我不能修改这样的值。

有什么方法可以让 "warnings being treated as errors" 消息消失吗？有人遇到过类似的问题吗？谢谢。

PD：Link 完整日志 here。

Answer 1

我终于找到了解决办法：

问题在于，即使安装了 4.9 版本的 gcc 和 g++ 编译器，容器也没有将它们作为默认值。所以，我不得不强制构建将这些编译器作为默认值：

  - cd build
  - export CC=/usr/bin/gcc-4.9
  - export CXX=/usr/bin/g++-4.9
  - cmake ..

由于这些是 CMakeFiles 应该运行的编译器，构建顺利通过。

Jsoncpp cmake 在 TravisCI 中执行 github 时抛出被视为错误的警告

Jsoncpp cmake throws warning treated as error when executed inside TravisCI for github

github

cmake

jsoncpp

travis-ci