Fix build error caused by -Werror=class-memaccess

[hooddanielc]

OS: Arch Linux
GCC Version: gcc (GCC) 8.2.1 20180831
Clang Version: 6.0.1 (tags/RELEASE_601/final)

Build Log Before Fix:

command: buck build //:yoga

Not using buckd because watchman isn't installed.
yoga/Yoga.cpp: In function ‘void YGZeroOutLayoutRecursivly(YGNodeRef)’:
yoga/Yoga.cpp:1854:51: error: ‘void* memset(void*, int, size_t)’ clearing an object of non-trivial type ‘struct YGLayout’; use assignment or value-initialization instead [-Werror=class-memaccess]
   memset(&(node->getLayout()), 0, sizeof(YGLayout));
                                                   ^
In file included from yoga/YGNode.h:11,
                 from yoga/Utils.h:9,
                 from yoga/Yoga.cpp:13:
yoga/YGLayout.h:12:8: note: ‘struct YGLayout’ declared here
 struct YGLayout {
        ^~~~~~~~
cc1plus: all warnings being treated as errors
Build failed: Command failed with exit code 1.
stderr: yoga/Yoga.cpp: In function ‘void YGZeroOutLayoutRecursivly(YGNodeRef)’:
yoga/Yoga.cpp:1854:51: error: ‘void* memset(void*, int, size_t)’ clearing an object of non-trivial type ‘struct YGLayout’; use assignment or value-initialization instead [-Werror=class-memaccess]
   memset(&(node->getLayout()), 0, sizeof(YGLayout));
                                                   ^
In file included from yoga/YGNode.h:11,
                 from yoga/Utils.h:9,
                 from yoga/Yoga.cpp:13:
yoga/YGLayout.h:12:8: note: ‘struct YGLayout’ declared here
 struct YGLayout {
        ^~~~~~~~
cc1plus: all warnings being treated as errors
    When running <c++ preprocess_and_compile>.
    When building rule //:yoga#compile-Yoga.cpp.o9b5477b5,default.
Parsing buck files: finished in 0.8 sec (100%)
Building: finished in 2.2 sec (100%) 10/10 jobs, 1 updated
  Total time: 3.3 sec

Build Log After Fix

command: buck build //:yoga

Not using buckd because watchman isn't installed.
Parsing buck files: finished in 0.8 sec (100%)
Building: finished in 0.6 sec (100%) 1/1 jobs, 0 updated
  Total time: 1.6 sec

All tests are passing

[facebook-github-bot]

passy has imported this pull request. If you are a Facebook employee, you can view this diff on Phabricator.

[davidaurelio]

Thanks for helping to make Yoga better.

I have a specific concern with using static_cast<>, and I believe that it isn’t necessary at all.

The memset call is probably a relict from the times when Yoga was pure C.

[facebook-github-bot]

passy has imported this pull request. If you are a Facebook employee, you can view this diff on Phabricator.