|
|
# How to Contribute to Abseil
|
|
|
|
|
|
We'd love to accept your patches and contributions to this project. There are
|
|
|
just a few small guidelines you need to follow.
|
|
|
|
|
|
NOTE: If you are new to GitHub, please start by reading [Pull Request
|
|
|
howto](https://help.github.com/articles/about-pull-requests/)
|
|
|
|
|
|
## Contributor License Agreement
|
|
|
|
|
|
Contributions to this project must be accompanied by a Contributor License
|
|
|
Agreement. You (or your employer) retain the copyright to your contribution,
|
|
|
this simply gives us permission to use and redistribute your contributions as
|
|
|
part of the project. Head over to <https://cla.developers.google.com/> to see
|
|
|
your current agreements on file or to sign a new one.
|
|
|
|
|
|
You generally only need to submit a CLA once, so if you've already submitted one
|
|
|
(even if it was for a different project), you probably don't need to do it
|
|
|
again.
|
|
|
|
|
|
## Contribution Guidelines
|
|
|
|
|
|
Potential contributors sometimes ask us if the Abseil project is the appropriate
|
|
|
home for their utility library code or for specific functions implementing
|
|
|
missing portions of the standard. Often, the answer to this question is "no".
|
|
|
We’d like to articulate our thinking on this issue so that our choices can be
|
|
|
understood by everyone and so that contributors can have a better intuition
|
|
|
about whether Abseil might be interested in adopting a new library.
|
|
|
|
|
|
### Priorities
|
|
|
|
|
|
Although our mission is to augment the C++ standard library, our goal is not to
|
|
|
provide a full forward-compatible implementation of the latest standard. For us
|
|
|
to consider a library for inclusion in Abseil, it is not enough that a library
|
|
|
is useful. We generally choose to release a library when it meets at least one
|
|
|
of the following criteria:
|
|
|
|
|
|
* **Widespread usage** - Using our internal codebase to help gauge usage, most
|
|
|
of the libraries we've released have tens of thousands of users.
|
|
|
* **Anticipated widespread usage** - Pre-adoption of some standard-compliant
|
|
|
APIs may not have broad adoption initially but can be expected to pick up
|
|
|
usage when it replaces legacy APIs. `absl::from_chars`, for example,
|
|
|
replaces existing code that converts strings to numbers and will therefore
|
|
|
likely see usage growth.
|
|
|
* **High impact** - APIs that provide a key solution to a specific problem,
|
|
|
such as `absl::FixedArray`, have higher impact than usage numbers may signal
|
|
|
and are released because of their importance.
|
|
|
* **Direct support for a library that falls under one of the above** - When we
|
|
|
want access to a smaller library as an implementation detail for a
|
|
|
higher-priority library we plan to release, we may release it, as we did
|
|
|
with portions of `absl/meta/type_traits.h`. One consequence of this is that
|
|
|
the presence of a library in Abseil does not necessarily mean that other
|
|
|
similar libraries would be a high priority.
|
|
|
|
|
|
### API Freeze Consequences
|
|
|
|
|
|
Via the
|
|
|
[Abseil Compatibility Guidelines](https://abseil.io/about/compatibility), we
|
|
|
have promised a large degree of API stability. In particular, we will not make
|
|
|
backward-incompatible changes to released APIs without also shipping a tool or
|
|
|
process that can upgrade our users' code. We are not yet at the point of easily
|
|
|
releasing such tools. Therefore, at this time, shipping a library establishes an
|
|
|
API contract which is borderline unchangeable. (We can add new functionality,
|
|
|
but we cannot easily change existing behavior.) This constraint forces us to
|
|
|
very carefully review all APIs that we ship.
|
|
|
|
|
|
|
|
|
## Coding Style
|
|
|
|
|
|
To keep the source consistent, readable, diffable and easy to merge, we use a
|
|
|
fairly rigid coding style, as defined by the
|
|
|
[google-styleguide](https://github.com/google/styleguide) project. All patches
|
|
|
will be expected to conform to the style outlined
|
|
|
[here](https://google.github.io/styleguide/cppguide.html).
|
|
|
|
|
|
## Guidelines for Pull Requests
|
|
|
|
|
|
* If you are a Googler, it is preferable to first create an internal CL and
|
|
|
have it reviewed and submitted. The code propagation process will deliver
|
|
|
the change to GitHub.
|
|
|
|
|
|
* Create **small PRs** that are narrowly focused on **addressing a single
|
|
|
concern**. We often receive PRs that are trying to fix several things at a
|
|
|
time, but if only one fix is considered acceptable, nothing gets merged and
|
|
|
both author's & review's time is wasted. Create more PRs to address
|
|
|
different concerns and everyone will be happy.
|
|
|
|
|
|
* For speculative changes, consider opening an [Abseil
|
|
|
issue](https://github.com/abseil/abseil-cpp/issues) and discussing it first.
|
|
|
If you are suggesting a behavioral or API change, consider starting with an
|
|
|
[Abseil proposal template](ABSEIL_ISSUE_TEMPLATE.md).
|
|
|
|
|
|
* Provide a good **PR description** as a record of **what** change is being
|
|
|
made and **why** it was made. Link to a GitHub issue if it exists.
|
|
|
|
|
|
* Don't fix code style and formatting unless you are already changing that
|
|
|
line to address an issue. Formatting of modified lines may be done using
|
|
|
`git clang-format`. PRs with irrelevant changes won't be merged. If
|
|
|
you do want to fix formatting or style, do that in a separate PR.
|
|
|
|
|
|
* Unless your PR is trivial, you should expect there will be reviewer comments
|
|
|
that you'll need to address before merging. We expect you to be reasonably
|
|
|
responsive to those comments, otherwise the PR will be closed after 2-3
|
|
|
weeks of inactivity.
|
|
|
|
|
|
* Maintain **clean commit history** and use **meaningful commit messages**.
|
|
|
PRs with messy commit history are difficult to review and won't be merged.
|
|
|
Use `rebase -i upstream/master` to curate your commit history and/or to
|
|
|
bring in latest changes from master (but avoid rebasing in the middle of a
|
|
|
code review).
|
|
|
|
|
|
* Keep your PR up to date with upstream/master (if there are merge conflicts,
|
|
|
we can't really merge your change).
|
|
|
|
|
|
* **All tests need to be passing** before your change can be merged. We
|
|
|
recommend you **run tests locally** (see below)
|
|
|
|
|
|
* Exceptions to the rules can be made if there's a compelling reason for doing
|
|
|
so. That is - the rules are here to serve us, not the other way around, and
|
|
|
the rules need to be serving their intended purpose to be valuable.
|
|
|
|
|
|
* All submissions, including submissions by project members, require review.
|
|
|
|
|
|
## Running Tests
|
|
|
|
|
|
If you have [Bazel](https://bazel.build/) installed, use `bazel test
|
|
|
--test_tag_filters="-benchmark" ...` to run the unit tests.
|
|
|
|
|
|
If you are running the Linux operating system and have
|
|
|
[Docker](https://www.docker.com/) installed, you can also run the `linux_*.sh`
|
|
|
scripts under the `ci/`(https://github.com/abseil/abseil-cpp/tree/master/ci)
|
|
|
directory to test Abseil under a variety of conditions.
|
|
|
|
|
|
## Abseil Committers
|
|
|
|
|
|
The current members of the Abseil engineering team are the only committers at
|
|
|
present.
|
|
|
|
|
|
## Release Process
|
|
|
|
|
|
Abseil lives at head, where latest-and-greatest code can be found.
|
