Treat compiler warnings as errors

[kunaltyagi]

This ensures that commits with warnings do not get a pass through CI.

Some commits have been already merged. This will track other warnings based on issues/PR

Current status per CI:

• Format
• MacOS Mojave
• MacOS Catalina
• Ubuntu 16.04
• Ubuntu 19.10
• Windows 32-bit
• Windows 64-bit
• Documentation: WIP by @aPonza

Current status of modules:

• Issues
  • Features: memset for Eigen::Matrix in integral_image2D.cpp #3368
  • Apps: QVTKWidget deprecated (in VTK >= 8.2 at least) #3370
• Pull requests
  • Common: Removes deprecated usage of getFields(cloud, fields) #3374
  • Segmentation: Reordered initializers in the correct order in `supervoxel_clus… #3375
  • People: Removes warnings about multi-line macro and not covered by if #3377
  • Surface/Nurbs: Suppress Nurbs warnings #3345
  • Recognition/Metslib: Remove deprecated throw specifier #3384
  • Tests: Fix pragma declaration for CI gcc, use "-Wdeprecated-declaratio… #3385, Move OMP version of MovingLeastSquares into a separate test case #3382 fixes Ignore deprecated use for testing surface::MovingLeastSquares #3378, Fix copy constructor warning when initializing CloudView #3425 fixes Warning regarding copy ctor in cloud_view.cpp #3405, Update unit tests to support both old and new GTest versions #3677 fixes GTest deprecated TYPED_TEST_CASE #3373
  • Registration: Fix the OpenMP errors/warnings in "ia_fpcs.hpp" #3389 fixes OMP compilation error in registration test #3376
  • Filters: Fix incorrect switch fallthrough in convolution operator #3429 fixes Implicit fallthrough warning in convolution.hpp #3367
  • Apps: Do not use deprecated function in stereo_ground_segmentation #3406 fixes Use of deprecated feature (extra unneeded args) in pcl_stereo_ground_segmentation #3403, Remove SupervoxelClustering::getColoredVoxelCloud() #3469 fixes Deprecated function getColoredVoxelCloud() is used in cloud composer #1427

Other related problems(?):

• AppleClang warnings: fixed by Fix sign-compare warnings issued by AppleClang #3777
  • Closed: Remove last few warnings left on MacOS CI #3785
  • missing field 'fst_bytesalloc' initializer: fixed by Add Catalina and Xcode toolchain for MacOS CI #3736
  • ld: warning: text-based stub file are out of sync. Falling back to library file for linking Possible solutions on SO Export SDK version of MacOS to prevent some linker warnings #3330 fixed by Add Catalina and Xcode toolchain for MacOS CI #3736
• Mismatch in flags for different compilers on the same system (GCC vs Clang on Linux)
• Mismatch in flags for different compilers on different systems (GCC vs AppleClang vs MSVC)

PS: This should be draft or normal PR? Draft

/fixes #2746

[taketwo]

PS: This should be draft or normal PR?

I think this is a draft: requires discussion, is not mean to be merged.

I moved Nurbs to the "Pull requests" section in your list since there is a PR in progress by Sergio.

[taketwo]

This ensures that commits with warnings do not get a pass through CI.

In reality, this change does not affect CI runs. In the CI config, we set several CXX flags explicitly, which prevents CMake from entering into the branch on line 112. Therefore, -Werror is not added on CI.

Let us add -Werror directly to the CI config and not add it to CMakeLists. The reason for the latter is that there are so many various versions of compilers in the wild that some may emit a warning somewhere. This will result in a failed build, unnecessary confusion for a user, and noise in the bug tracker.

[kunaltyagi]

Let us add -Werror directly to the CI config

This makes more sense.

[taketwo]

It took 20s for MacOS job to fail the build 😆

[kunaltyagi]

It took 20s for MacOS job to fail the build

The error is quite unexpected. Do check it

In file included from In file included from /Users/vsts/agent/2.155.1/work/1/s/common/src/pcl_base.cpp:/Users/vsts/agent/2.155.1/work/1/s/common/src/point_types.cpp39::
37In file included from :
In file included from /Users/vsts/agent/2.155.1/work/1/s/common/include/pcl/point_types.h:42:
In file included from /Users/vsts/agent/2.155.1/work/1/s/common/include/pcl/pcl_macros.h:61:
/Applications/Xcode_10.1.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/cmath:313:9: error: no member named 'signbit' in the global namespace
using ::signbit;

[taketwo]

After merging #3477, the Ubuntu 16.04 job will be clean of warnings. I propose to use this opportunity to enable -Wall at least in that job. We'll continue to track progress about making the rest of our jobs warning-free in this PR.

[kunaltyagi]

For 19.04, the warnings are mainly due to memset and memcpy. I might be able to remove some of the memset warnings soon. I tried to make some types trivial in PCL, but that experiment didn't go well. Just writing this to keep track