simple-yaml: add compatibility for older compilers

[Zeeno-atl]

Specify library name and version: simple-yaml/0.2.1

The previous PR #8705 didn't generate any packages due to the fact that no compiler in the PR pipeline supported <source_location> header. Adding compatibility library source_location solves this issue and thus it should generate some packages this time (hopefully). And since there were no packages online, I also bumped the version removing the older one.

---

• I've read the guidelines for contributing.
• I've followed the PEP8 style guides for Python code in the recipes.
• I've used the latest Conan client version.
• I've tried at least one configuration locally with the
  conan-center hook activated.

[Zeeno-atl]

I need a cap here. It took me a while to figure out what is going on, but now I guess I understand. The Docker image a clang11 is based on is FROM ubuntu:bionic. This ships with the libstdc++-7.5 . The conan/cmake compiles the code with GCC's libstdc++-7.5 header files. This means that even though the <filesystem> header is supported by Clang's libc++ since version 7 and GCC's libstdc++ since version 8, the compilation fails.

In the Dockerfile there is a

    # Further LLVM packages not installed by the llvm.sh script
    && apt-get install -y --no-install-recommends --no-install-suggests \
       libc++-11-dev \
       libc++abi-11-dev \

attempt to install libc++-11, but it is in fact not used by the compiler. I am not sure where the error is.
Should conan set linking against libc++ (-stdlib=libc++) instead of libstdc++ when compiling using Clang/LLVM?
Should Dockerfile include a bit more recent libstdc++ when compiling with a recent Clang/LLVM version?
If both of the answers are NO, what is the point of using a recent compiler with archaic standard libraries?

EDIT: I guess it is not only linking, but setting include folders as well to the proper version of header files. I am a mere user of build systems, not sure how to set things up.

[SSE4]

seems like more or less the same problem as with #8927
in general, it seems like libstdc++ and clang versions are orthogonal and independent, and probably it makes sense to install the latest (or at least more recent) libstdc++ version on clang machines. but that may break binary compatibility (needs to be carefully checked, if binaries will require new version of libstdc++.so, and if they will be able to run on the vanilla distro).

[uilianries]

It's a peculiar situation, and we have few options here, let me list them:

• Update Docker image conanio/clang11 with a newer libstdc++ version
  • It should fix your problem, but at a high risk of breaking other packages. Conan Center has tons of packages that we can't validate possible side effects, like runtime errors.
• Switch the Docker images from conanio/clang11 to conanio/clang11-ubuntu16.04
  • The newer Docker images are running more aligned compilers with their respective libstdc++ and libc++ versions. However, the current conanio/clang11 uses Ubuntu 18:04 which contains a newer version of glibc, so can not do it, otherwise it would break all packages in Conan Center.
• Raise InvalidConfigurationError and ignore Clang11 for now
  • At some point, Clang 14 will be released and Clang11 will no longer produce packages in Conan Center

We understand the situation, but we can not risk the current stability due this need. Unfortunately, we will need to skip Clang 11 for now and wait for Clang 13 become stable, then, stop to use Clang 11.

[SSE4]

yes, for now, we can't change clang11 docker image, so let's add the following code snippet to affected recipes:

def validate(self):
    ....
    if self.settings.compiler == "clang" and self.settings.compiler.libcxx in ["libstdc++", "libstdc++11"] and self.settings.compiler.version == "11":
        raise ConanInvalidConfiguration("clang 11 with libstdc++ is not supported due to old libstdc++ missing C++17 support")

this way, it will skip clang11 + libstdc++ configuration, but will still build clang11 + libc++.

[conan-center-bot]

All green in build 4 (f5e0cda69f8d1e1699246210198afb54fef17480):

• simple-yaml/0.2.2@:
  All packages built successfully! (All logs)

[ghost]

I detected other pull requests that are modifying simple-yaml/all recipe:

• [simple-yaml] Add version 0.2.2 #9392

This message is automatically generated by https://github.com/ericLemanissier/conan-center-conflicting-prs so don't hesitate to report issues/improvements there.

[jgsogo]

I've seen there had been a problem in the past uploading 0.2.0 and that version was not available in the center. Version 0.2.2 has been successfully uploaded and it is available.

I think we are fine, no need to recover the old version.

Thanks for your contribution here!