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Understanding the Phacility CLA
Phabricator Contributor Documentation (Contributing in Detail)

Describes the Contributor License Agreement (CLA).


IMPORTANT: This document is not legal advice.

Phacility requires contributors to sign a Contributor License Agreement (often abbreviated "CLA") before we can accept contributions into the upstream. This document explains what this document means and why we require it.

This requirement is not unusual, and many large open source projects require a similar CLA, including Python, Go, jQuery, and Apache Software Foundation projects.

You can read more about CLAs and find more examples of companies and projects which require them on Wikipedia's CLA page.

Our CLA is substantially similar to the CLA required by Apache, the "Apache Individual Contributor License Agreement V2.0". Many projects which require a CLA use this CLA or a similar one.

Why We Require a CLA

While many projects require a CLA, others do not. This project requires a CLA primarily because:

  • it gives us certain rights, particularly the ability to relicense the work later;
  • it makes the terms of your contribution clear, protecting us from liability related to copyright and patent disputes.

More Rights: We consider the cost of maintaining changes to greatly outweigh the cost of writing them in the first place. When we accept work into the upstream, we are agreeing to bear that maintenance cost.

This cost is not worthwhile to us unless the changes come with no strings attached. Among other concerns, we would be unable to redistribute Phabricator under a different license in the future without the additional rights the CLA gives us.

For a concrete example of the problems this causes, Bootstrap switched from GPLv2 to MIT in 2012-2013. You can see the issue tracking the process and read about what they had to go through to do this here:

This took almost 18 months and required a huge amount of effort. We are not willing to encumber the project with that kind of potential cost in order to accept contributions.

The rights you give us by signing the CLA allow us to release the software under a different license later without asking you for permission, including a license you may not agree with.

They do not allow us to undo the existing release under the Apache license, but allow us to make an additional release under a different license, or release under multiple licenses (if we do, users may choose which license or licenses they wish to use the software under). It would also allow us to discontinue updating the release under the Apache license.

While we do not currently plan to relicense Phabricator, we do not want to give up the ability to do so: we may want or need to in the future.

The most likely scenario which would lead to us changing the license is if a new version of the Apache license is released. Open source software licenses are still largely untested in the US legal system, and they may face challenges in the future which could require adapting them to a changing legal environment. If this occurs, we would want to be able to update to a newer version of the license which accounted for these changes.

It is also possible that we may want to change open source licenses (for example, to MIT) or adopt dual-licensing (for example, both Apache and MIT). We might want to do this so that our license is compatible with the licenses used by other software we want to be distributed alongside.

Although we currently believe it is unlikely, it is also possible we may want to relicense Phabricator under a closed, proprietary, or literally evil license. By signing the CLA, you are giving us the power to do this without requiring you to consent. If you are not comfortable with this, do not sign the CLA and do not contribute to Phabricator.

Limitation of Liability: The second benefit the CLA provides is that it makes the terms of your contribution explicitly clear upfront, and it puts us in a much stronger legal position if a contributor later claims there is ambiguity about ownership of their work. We can point at the document they signed as proof that they consented to our use and understood the terms of their contribution.

SCO v. IBM was a lawsuit filed in 2003 alleging (roughly) that IBM had improperly contributed code owned by SCO to Linux. The details of this and the subsequent cases are very complex and the situation is not a direct parallel to anything we are likely to face, but SCO claimed billions of dollars in damages and the litigation has now been ongoing for more than a decade.

We want to avoid situations like this in the future by making the terms of contribution explicit upfront.

Generally, we believe the terms of the CLA are fair and reasonable for contributors, and that the primary way contributors benefit from contributing to Phabricator is that we publish and maintain their changes so they do not have to fork the software.

If you have strong ideological reasons for contributing to open source, you may not be comfortable with the terms of the CLA (for example, it may be important to you that your changes are never available under a license which you haven't explicitly approved). This is fine and we can understand why contributors may hold this viewpoint, but we can not accept your changes into the upstream.

Corporate vs Individual CLAs

We offer two CLAs:

These are both substantially similar to the corresponding Apache CLAs.

If you own the work you are contributing, sign the individual CLA. If your employer owns the work you are contributing, have them sign the corporate CLA.

If you are employed, there is a substantial possibility that your employer owns your work. If they do, you do not have the right to contribute it to us or assign the rights that we require, and can not contribute under the individual CLA. Work with your employer to contribute under the corporate CLA instead.

Particularly, this clause in the individual CLA is the important one:

  1. You represent that you are legally entitled to grant the above license. If

your employer(s) has rights to intellectual property that you create that includes your Contributions, you represent that you have received permission to make Contributions on behalf of that employer, that your employer has waived such rights for your Contributions to Phacility, or that your employer has executed a separate Corporate CLA with Phacility.

Ownership of your work varies based on where you live, how you are employed, and your agreements with your employer. However, at least in the US, it is likely that your employer owns your work unless you have anticipated conflicts and specifically avoided them. This generally makes sense: if you are paid by your employer for your work, they own the product of your work and you receive salary and benefits in fair exchange for that work.

Your employer may have an ownership claim on your work even if you perform it on your own time, if you use their equipment (like a company laptop or phone), resources, facilities, or trade secrets, or signed something like an "Invention Assignment Agreement" when you were hired. Such agreements are common. The details of the strength of their claim will vary based on your situation and local law.

If you are unsure, you should speak with your employer or a lawyer. If you contribute code you do not own under the individual CLA, you are exposing yourself to liability. You may also be exposing us to liability, but we'll have the CLA on our side to show that we were unwilling pawns in your malicious scheme to defraud your employer.

The good news is that most employers are happy to contribute to open source projects. Incentives are generally well aligned: they get features they want, and it reflects well on them. In the past, potential contributors who have approached their employers about a corporate CLA have generally had little difficulty getting approval.