box2d: Do not force warnings as errors by default

[skhaz]

Summary

Changes to recipe: box2d/3.0.0

Motivation

This (hopefully) closes #25797

Details

Box2D compiles on Linux, Windows, and macOS, but not for WebAssembly using emsdk. This PR attempts to address the compilation error I’m encountering and should not impact other users.

---

• Read the contributing guidelines
• Checked that this PR is not a duplicate: list of PRs by recipe
• Tested locally with at least one configuration using a recent version of Conan

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[skhaz]

Please help @memsharded

[jcar87]

see comment

[jcar87]

Hi @skhaz - thanks for your contribution.

Doing it this way does not take into account the compiler - they are passed unconditionally to all compilers regardless of whether they understand those particular flags. Additionally, -O3 would trample and override the user's build_type setting - since it is being applied unconditionally.

This looks like a bug in the upstream recipe itself - I would first ensure that it is, at the very least, reported upstream to the maintainers: https://github.com/erincatto/box2d

In this instance, however I would possibly advise simply setting

tc.cache_variables["CMAKE_COMPILE_WARNING_AS_ERROR"] = False

since this is failing on emscriptem because this setting is too strict

[skhaz]

Thank you, I have updated my pull request and raised an issue on box2d repository.

[AbrilRBS]

Thanks @skhaz happy to see that you reported an issue upstream, I'm sure they'll appreciate it :)

The current workaround looks good to me to get this to compile, and if a new version is generated with upstream's fix, we'll be happy to add it :)

[skhaz]

Thank you @AbrilRBS. I will keep an eye and when they provide a fix I will let you know.

addressed

[jcar87]

Thanks @skhaz ! Running this on CI - please let us know if with that setting, it at least lets you proceed :D

[skhaz]

Is there a way to test this branch locally, I mean, instead of conan pulling the packages specs from the main repository/internet, fetch from my branch?

[jcar87]

Is there a way to test this branch locally, I mean, instead of conan pulling the packages specs from the main repository/internet, fetch from my branch?

cd conan-center-index/recipes/box2d/all
conan export . --version=2.4.2

and then add --build=missing when you are solving the graph for a consumer (e.g. conan install)
or you can call conan create . --version=2.4.2 from the same directory and that will trigger the build

[lindequist]

First of all, sorry if I commenting in the wrong place. I was also trying to use box2d/3.0.0 with emsdk/3.1.50, and I also got errors a la:

.conan2/p/b/box2d6487a51d42777/b/src/src/contact_solver.c:810:6: error: loop not vectorized: the optimizer was unable to perform the requested transformation; the transformation might be disabled or specified as part of an unsupported transformation ordering [-Werror,-Wpass-failed=transform-warning]
  810 | void b2WarmStartContactsTask( int startIndex, int endIndex, b2StepContext* context, int colorIndex )

I tried with the changes merged into master here, but it didn't fix the issue for me. Then, just for testing, I checked out conan-center-index and added this line instead in recipes/box2d/all/conanfile.py:

tc.cache_variables["CMAKE_C_FLAGS"] = "-Wno-error=pass-failed"

After exporting using conan export . --version=3.0.0, I was able to build the box2d dependency, and the warning that was treated as an error before is now just a warning.

[skhaz]

erincatto/box2d#832 (comment)