cmake throws warning treated as error message when executed inside TravisCI

[gigena-git]

I'm trying to use jsoncpp as part of my project. The end goal is to get the following files:

• dist/jsoncpp.cpp (need to run python amalgamate.py)
• dist/json/json.h (need to run python amalgamate.py)
• dist/json/json-forwards.h (need to run python amalgamate.py)
• src/lib_json/libjsoncpp.a (need to run cmake)

So, I have a .travis.yml file inside my repo (which will always run whenever I push to github) that looks like this:

---
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:
- cp src/lib_json/libjsoncpp.a /usr/local/lib/

The yaml runs perfectly up until the make statement (so I'm able to retrieve the first three files I need), but then it logs the following message:

$ 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 .

Apparently, the build fails because these two warnings are treated as errors. I have also noticed that versions 4.9 of gcc and gpp are installed correctly, but I don't know if the compiler used is the one I am telling it to use.

Is there any way I can make the "warnings being treated as errors" message go away? Anyone had a similar problem with a similar build? Should I try a different approach to get src/lib_json/libjsoncpp.a? Thank you.

PD: Link to full log here.

[ya1gaurav]

Check:
https://github.com/open-source-parsers/jsoncpp/blob/master/CMakeLists.txt#L115
https://github.com/open-source-parsers/jsoncpp/blob/master/CMakeLists.txt#L116

You can remove flag - -Werror=conversion
Or change configuratio options in:
https://github.com/open-source-parsers/jsoncpp/blob/master/CMakeLists.txt#L9
https://github.com/open-source-parsers/jsoncpp/blob/master/CMakeLists.txt#L10

[cdunn2001]

@ya1gaurav, let's change the default. I don't think we can fix CZString without a major version bump. Could you submit a PR? (I'm just catching up from vacation.)

[aakarsh]

please do this. seeing this error too. Am able to compile fine without -W error on conversion flag