CONTRIBUTING.md

Contributing to Sen

First off, thanks for taking the time to contribute! ❤️

All types of contributions are encouraged and valued. Please make sure to read the relevant section before making your contribution. It will make it a lot easier for us maintainers and smooth out the experience for all involved.

I Have a Question

If you want to ask a question, we assume that you have read the available documentation.

Before you ask a question, it is best to search for existing issues that might help you. In case you have found a suitable issue and still need clarification, you can write your question in this issue.

Code contributions

Sen has only recently been released as open source, and the process for taking in code from outside the team is not in place yet. Until it is, we are holding external code contributions.

Feedback, issue reports and feature suggestions are welcome now and will be evaluated.

The sections below describe how a change is built, tested and proposed. That is how the project works today, and it is what will apply when contributions open.

Building and Testing

The README covers the build. For a contribution, build with the tests enabled and run them before opening the pull request:

conan install . --profile:all=sen_gcc --build=missing -o "sen/*:with_tests=True"
conan build . --profile:all=sen_gcc -o "sen/*:with_tests=True"
pipx install junitparser                                 # run_tests merges the ctest reports with it
cmake --build build/gcc/Release --target run_tests

conan build resolves the graph again, so an option left off it falls back to its default and rewrites the build folder conan install just configured. Leave it off and the tests are dropped, and run_tests reports that it found none.

run_tests runs the suite in two passes: the ordinary tests, then the ones marked flaky, which are retried until they pass. While working on one library, run_unit_tests is quicker.

If your editor supports devcontainers, the one under .devcontainer/ already has the compilers, Conan and the test tools installed.

Editors

conan install writes CMakeUserPresets.json at the repository root, pointing at the presets Conan generated for the build folder. Run it once, then open the repository folder in your editor and pick the preset it lists: conan-gcc-release for the profiles above, or conan-msvc-release when you build with sen_msvc on Windows. VS Code reads presets through the CMake Tools extension; CLion and Visual Studio read them natively, pointed at the folder rather than at CMakeLists.txt.

Two things decide what your editor shows you, and both are set before CMake ever runs:

• -o "sen/*:with_tests=True" and -o "sen/*:with_examples=True", on the conan build line as well as the conan install one. Without them the project has no test or example targets at all, and the editor is not hiding them.
• The environment you ran conan install in. The generated files hold absolute paths, so a build folder belongs to the environment that configured it.

In a container

The devcontainer is the least work: its image already carries the compilers, Conan and the editor tools, and its setup step installs the profiles and selects the one matching the container's architecture. In its terminal, the same two steps are:

conan install . --build=missing -o "sen/*:with_tests=True"
cmake --build --preset conan-gcc-release --target run_tests

cmake --build reads the build folder rather than resolving the graph again, so the option does not have to be repeated here.

No package-manager settings are needed there, unlike on a bare machine: the image already has the system libraries, and inside the container you are not root.

Editors mount the sources at different paths, /workspaces/<name> and /IdeaProjects/<name> among them, and Conan writes that path into the presets. So configure where you build. If you move between a container and your machine, delete CMakeUserPresets.json and re-run conan install: Conan keeps entries for build folders that no longer exist, and CMake then refuses to read the file at all. A build folder configured in a container also cannot be built on the host, and the other way round; the error names a directory that cannot be created.

CLion builds the profile from the preset by itself, so there is no need to add one by hand. If its run widget stays empty after a reload, the project model is still loading; the commands above work from the terminal regardless.

Container permissions

Some tests take a fallback path unless the container was started with the permission they need. Neither is needed to build Sen or run the suite.

python3 .github/scripts/check_container_capabilities.py

• --ulimit rtprio=99, for the real-time scheduling policy. The devcontainer asks for this; it is safe to request anywhere.
• --device=/dev/cpu_dma_latency, for the idle latency control. Not asked for by default, because Docker refuses to start the container when the device is absent. Add it to runArgs in your own checkout if you need those tests.

CI sets SEN_REQUIRE_CAPABILITIES, which makes the same check fail when a permission it asked for is missing.

Running the container yourself

The devcontainer does this for you. Without one:

# Once. --target dev is the CI image plus a debugger and graphviz.
docker build --target dev -t sen-dev tools/ci

# A shell in it. The repository is mounted at the path it has outside, so a worktree's
# .git still resolves; the caches are volumes, so they outlive the container.
docker run --rm -it -v "$PWD:$PWD" -w "$PWD" \
    -v sen-conan:/home/sen/.conan2 -v sen-ccache:/home/sen/.ccache \
    --ulimit rtprio=99 sen-dev bash

Then, inside it:

git config --global --add safe.directory "$PWD"
conan config install .conan/profiles/ --target-folder ~/.conan2/profiles/
conan install . --profile:all=sen_gcc --build=missing -o "sen/*:with_tests=True"
conan build . --profile:all=sen_gcc -o "sen/*:with_tests=True"

What bites:

• --profile:all, not --profile. The bare form sets only the host profile, and Conan then looks for a build profile called default, which the repository does not ship.
• --rm discards safe.directory with the container, so a script that runs one container per command needs that line in each of them. Without it conan install fails where it calls git describe.
• Sanitizer builds need --security-opt seccomp=unconfined on the docker run, and a clang profile. The runtimes call personality(ADDR_NO_RANDOMIZE), which the default seccomp profile blocks, and the failure reads as a compiler crash.

Commit Messages and Pull Requests

Commit subjects follow the conventional format type(scope): summary:

• Types in use: feat, fix, test, chore, refactor, docs, build, ci, perf, revert. The scope is optional, lowercase and without spaces (fix(core,kernel): ...); a ! before the colon marks a breaking change.
• Keep the subject under 72 characters, without a trailing period.
• A body is optional. When one helps, one to three sentences explaining why the change is needed are enough; the diff shows what changed.

gitlint checks these rules, through pre-commit. The devcontainer and the image already carry it, so in a container there is nothing to install. On a bare machine pip install pre-commit fails on current Debian and Ubuntu with externally-managed-environment; use pipx install pre-commit, or a virtual environment.

Then pre-commit install once after cloning, which installs the file hooks and the commit message hook together.

Pull requests are squash-merged, so the pull request title becomes the commit subject on main and follows the same format. Keep each pull request to a single logical change: whatever lands is one commit.

Reporting Bugs

A good bug report shouldn't leave others needing to chase you up for more information. Therefore, we ask you to investigate carefully, collect information and describe the issue in detail in your report. Please complete the following steps in advance to help us fix any potential bug as fast as possible.

• Determine if your bug is really a bug and not an error on your side e.g. using incompatible environment components/versions (Make sure that you have read the documentation.
• To see if other users have experienced (and potentially already solved) the same issue you are having, check if there is not already a bug report existing for your bug.
• Collect information about the bug:
  • Stack trace (Traceback)
  • OS, Platform and Version
  • Possibly your input and the output
  • Can you reliably reproduce the issue? And can you also reproduce it with older versions?
  • Expected behavior vs Current behavior

If you run into an issue with the project:

• Open an issue. (Since we can't be sure at this point whether it is a bug or not, we ask you not to talk about a bug yet and not to label the issue.)
• Explain the behavior you would expect and the actual behavior.
• Please provide as much context as possible and describe the reproduction steps that someone else can follow to recreate the issue on their own. This usually includes your code. For good bug reports you should isolate the problem and create a reduced test case.
• Provide the information you collected in the previous section.

Suggesting Enhancements

Before submitting a suggestion of enhancement:

• Read the documentation carefully and find out if the functionality is already covered, maybe by an individual configuration.
• Perform a search to see if the enhancement has already been suggested. If it has, add a comment to the existing issue instead of opening a new one.
• Find out whether your idea fits with the scope and aims of the project. It's up to you to make a strong case to convince the project's developers of the merits of this feature. Keep in mind that we want features that will be useful to the majority of our users and not just a small subset.

Enhancement suggestions:

• Use a clear and descriptive title for the issue to identify the suggestion.
• Provide a step-by-step description of the suggested enhancement in as many details as possible.
• Describe the current behavior and explain which behavior you expected to see instead and why. At this point you can also tell which alternatives do not work for you.
• You may want to include screenshots and animated GIFs which help you demonstrate the steps or point out the part which the suggestion is related to.
• Explain why this enhancement would be useful to most Sen users. You may also want to point out the other projects that solved it better and which could serve as inspiration.