CMake 3.11 will stop supporting multiline cache strings

[osrf-migration]

Original report (archived issue) by Martin Pecka (Bitbucket: peci1).

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Gazebo uses multiline CMake cache strings in files like https://github.com/osrf/gazebo/blob/45fb70f6a44696739ba853823980fe0a006056a2/gazebo/common/CMakeLists.txt#L219 .

CMake 3.11 will stop supporting this: https://cmake.org/cmake/help/v3.15/release/3.11.html#other-changes .

Practically, it doesn’t seem to be a big problem, because if I understand it correctly, this cache string is actually never loaded from the cache as its only usage is being directly handed off to configure_file. I verified it and the generated file config.hh looks correct and contains many include lines.

This is what CMakeCache.txt looks like when built with CMake 3.15:

‌

//Common Headers
common_headers:INTERNAL= #include "gazebo/common/Animation.hh"
# WARNING: Value of common_headers contained a newline and was
#  truncated. Original value:
#  #include "gazebo/common/Animation.hh"
# \n #include "gazebo/common/Assert.hh"
# \n #include "gazebo/common/AudioDecoder.hh"
# \n #include "gazebo/common/Battery.hh"
# \n #include "gazebo/common/Base64.hh"
# \n #include "gazebo/common/BVHLoader.hh"
...

And these warnings are written to the console:

‌

CMake Warning:                                                                                      
  Value of common_headers contained a newline; truncating   

So, the question is: is it still needed to save these variables to cache?

[osrf-migration]

Original comment by Steve Peters (Bitbucket: Steven Peters, GitHub: scpeters).

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good call, these shouldn't need to be in the cache

see pr #3138

[osrf-migration]

Original comment by Steve Peters (Bitbucket: Steven Peters, GitHub: scpeters).

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• changed state from "new" to "resolved"

pr #3138