# Contributing to Graphene

First off, thank you for your interest in contributing to Graphene!

In general, code contributions should be submitted to the Graphene project using a Pull Request.

## Reporting bugs

In order to report a problem or get help, please open an issue in the issue tracker here:

https://github.com/oscarlab/graphene/issues

## Architectural Changes

Major reorganizations, architectural changes, or code reorganization are best discussed with the maintainers
in advance of writing code.  We welcome contributions, and would hate for anyone to waste time implementing
a change that will not be accepted for a design flaw.  It is much better to reach out for advice first
by emailing:

  support@graphene-project.io

Or you can see the archives at this google group:

  https://groups.google.com/forum/#!forum/graphene-support

Simple bugfixes need not have advance discussion, but we welcome queries from newcomers.

## Branch Names

For work in progress (for team members), please use your name/userid as a prefix in the branch name.  For example, if user 'jane' is adding feature 'foo', the branch should be named: 'jane/foo'.

For new contributors, the branch will likely be on a fork of the repository.

Otherwise, branches without this prefix should only be created for a specific purpose, as approved by the maintainers.

## Pull Requests

The primary mechanism for submitting code changes is with a pull request (PR).

In general, a PR should:

1. Address a single problem; i.e., it should add one feature or fix one issue.  Fixes for distinct issues should be separated into multiple PRs.
2. Clearly explain the problem and solution in the PR and commit messages, using grammatically correct English.
3. Include unit tests for the new behavior or bugfix, except in special circumstances, namely: when designing a unit test is difficult (e.g., the code is deep enough in Graphene that it would require extra hooks for testing) or cannot be easily tested (e.g., a performance fix).
4. Follow [project style guidelines](CODESTYLE.md).

### PR Life Cycle

1. A PR is created. If the authors know a good candidate for the review (e.g., the author of the specific component) they should assign a suggested reviewer on GitHub.
2. From this point on the branch is public, which means that one should ask reviewers' permission before doing a force-push.
3. Reviewers shouldn’t push commits to the PR, only the authors are allowed to do so.
4. Reviewers add comments to the changes.
5. The author discusses the remarks and implements fixes in separate commits. Loop to point 4. until all comments are resolved and all reviewers mark the PR as approved.
6. The author squashes fix-up commits with original ones, rebases them to current master (in case of conflicts) and, if needed and approved by the reviewers, does a force-push to share the final version of the changes.
7. The reviewer is responsible for ensuring that the squash is a real squash without any additional changes (except resolving conflicts). Only after that they can execute rebase+merge to master.

### PR Merging Policy

Before a pull request is merged, it must:

  1. Pass all CI tests
  2. Follow [project style guidelines](CODESTYLE.md).
  3. Introduce no new compilation errors or warnings
  4. Have all discussions from reviewers resolved
  5. Have a clear, concise and grammatically correct comments and commit messages.
  6. Have a quorum of approving reviews from maintainers and/or waited an appropriate amount of time.  This can be:
     1. 3 approving reviews
     2. 2 approving reviews and 5 days since the PR was created
     3. 1 approving review and 10 days since the PR was created, if the author is a maintainer

Additional reviews from anyone are welcome.

### Reviewing Guidelines

1. All commits must be atomic (i.e., no unrelated changes in the same commit, no formatting fixes mixed with features, no moving files and changing them at the same time).
2. Meaningful commit messages (it’s much easier to get them right if commits are really atomic). Should include which component was changed ({Linux,SGX} PAL / shim / glibc) in the format “[component] change description”.
3. Every PR description should include: what’s the purpose of the changes, what is changed (and how, in case of redesigning a component), how to test the changes.
4. Is it possible to implement this change in a significantly better way?
5. It’s C, so check for common problems: correct buffer sizes, integer overflows, memory leaks, violations of pointer ownership etc.
6. Verify if all macro parameters are used with additional parentheses.
7. Check for race conditions.
8. Check if all errors are checked and properly handled.
9. Suggest adding assertions (if appropriate). Especially for ensuring invariants after a complex operation.
10. Check for possibilities of undefined behaviours (e.g. signed overflow).
11. If the PR fixed a bug, there should be a regression test included in the change. The commit containing it should be committed before the fix, so the reviewer can easily run it before and after the fix.
12. Code style must follow our guidelines (see below).

### Style Guidelines

See [style guidelines](CODESTYLE.md).

## Running Regression Tests by Hand

All of our regression tests are automated in Jenkins jobs (see the
Jenkinsfiles directory), and this is the ultimate documentation for
application-level regression tests, although most tests can be run with
`make regression` or, in the worst case, should have a simple script called by Jenkins.

We also have (and are actively growing) PAL and shim unit tests.

To run the PAL tests:

```Bash
cd Pal/regression
make regression
```

For SGX, one needs to do the following:

```Bash
cd Pal/regression
make SGX=1 regression
```

If a test fails unexpectedly, one can use the KEEP_LOG=1 option to get the complete output.

One can run tests manually:

```sh
PYTHONPATH=path/to/graphene/Scripts
PAL_LOADER=path/to/pal-Linux
export PYTHONPATH PAL_LOADER
python3 -m pytest -v -rs test.py
```

It is also possible to run subset of tests:

```sh
# after env export
python3 -m pytest -v -rs test.py::TC_01_Bootstrap
python3 -m pytest -v -rs test.py::TC_01_Bootstrap::test_100_basic_boostrapping
```

The shim unit tests work similarly, and are under LibOS/shim/test/regression

### LTP

Graphene passes a subset of the LTP tests.  New changes should not break currently passing
LTP tests (and, ideally, might add new passing tests).  LTP is currently only supported on
the Linux host.

To run these tests:

```Bash
cd LibOS/shim/test/apps/ltp
make
./syscalls.sh
```
