Removed TODOs.

Replaced clang-tidy-5.0 with clang-tidy-8 in all Docker containers.

Thanks! I merged the issue branch. Feel free to close this once you updated the Docker images.

Added a new TODO item.

Yes I can install clang-tidy-8 in the Docker containers. I will remove the old version as soon as this issue is merged.

OK, let's go ahead with clang-tidy-8 then. Cedric, can you please install clang-tidy-8 instead of clang-tidy-5.0 in the Docker containers?

No objections to the pull request from my side. I don't know why the PyYAML thing is there, but I assume it's there for a reason. If someone wants to object to this, please speak up. No strong feelings about the version number as long as it's supported on the current stable Ubuntu. Someone else will have to take care of docker.

Before we merge this, we need to install the new clang-tidy version in our Docker containers.

I prepared a pull request for this. It uses clang-tidy-8, but we can use a different version if you prefer: https://bitbucket.org/jendrikseipp/downward/pull-requests/150

The new version uncovered some unnecessary copies, which I fixed in the default branch already: https://bitbucket.org/jendrikseipp/downward/commits/51ecb6fb3d49ee6013f150add6180728b2b660e1

Update summary.

For now, I'd only change the version.

Do you just want to change the version or also enable more tests? If the latter, please tell us which changes to the codebase the new code tests would require.

We currently use clang-tidy-5.0, which is only available in Ubuntu 16.04 and 18.04. To support newer Ubuntu versions, we need to switch to a newer clang-tidy version. All of clang-tidy 6.0, 7.0 and 8 are viable options (https://packages.ubuntu.com/search?lang=en&keywords=clang-tidy&searchon=names). Version 6.0 has the advantage that it is available on Ubuntu 16.04. The newer versions, on the other hand, offer more code tests (https://releases.llvm.org/7.0.0/tools/clang/tools/extra/docs/ReleaseNotes.html#improvements-to-clang-tidy, https://releases.llvm.org/8.0.0/tools/clang/tools/extra/docs/ReleaseNotes.html#improvements-to-clang-tidy). In my opinion, it would be fine to use clang-tidy-8 since it has a greater chance of being available in coming Ubuntu releases. What are your thoughts?