As one of the kernel DCO advocates, I’ve written many times about using the DCO instead of a CLA for copyright and patent contributions under open source licences. In spite of my obvious biases, I’ll try to give a factual overview of the cases for the DCO and CLA system. First, it should be noted that both the DCO and any CLA are types of Contribution Agreements (a set of terms by which contributors are agreeing to be bound). It should also be acknowledged that the DCO is a far more recent invention than CLAs. The DCO was first pioneered by the Linux kernel in 2004 (having been designed by Diane Peters, then of OSDL) and was subsequently adopted by a broad range of open source projects. However, in legal terms, the DCO is much less well understood than a standard CLA type agreement between the contributor and some entity, which is largely the reason you find a number of lawyers still advocating for the use of CLAs in various open source projects: because they’d like to stick with something that has more miles on it, or because they’re invested in the older model of community, largely pioneered by Apache. The biggest problem today is that the operation of most CLAs is asymmetrical: they take from the contributor more rights than the open source code actually needs, so lets begin with a summary of each type of Contribution Agreement.
The DCO is a legal representation by the contributor to everyone who might ever use the code. It requires no second party on the other side to counter sign it or act as the receiving entity, so it exactly mirrors the inbound=outbound licensing model first coined by Richard Fontana. The DCO explicitly grants to all downstream recipients only the exact rights the Open Source licence requires (and nothing more). In this sense it is fully symmetrical: the rights granted by the contributor are the same as the rights received by the downstream (i.e. inbound=outbound). Every contributor under the DCO retains their own copyright (or their company does if the contribution is a work for hire). The main alleged disadvantage of the DCO is that it encourages distributed ownership and makes it very hard to change the licence of the project because each contributor has only granted the rights necessary for the current licence, so if the new one requires more or different rights, all the current contributors have to re-grant those new or different rights (which can be a huge number of people for large long running projects). Since the DCO is a representation to everyone and requires no receiving entity, the project collecting the code doesn’t require any formal legal entity, like a foundation, to operate and thus the DCO gives rise to a truly lightweight structure for any project. The other big advantage of the DCO is that all of the representations are tracked by the Signed-off-by: tag on the commit, which goes in the git repository of the project code, so anyone with a clone of the repository has complete access to information about who changed what and where their DCO signoff is.
All current Open Source CLAs are structured as agreements between the contributor and a second party. Most often, the second party is a Foundation or a Corporation, making them quite heavy weight in terms of setup, admin and overhead. Every current CLA that I know about takes more rights from the contributor than the open source licence actually requires. For instance the Apache Individual CLA grants the right to copy, derive and sublicence to the Apache foundation who then relicence the contribution to the project usually under the Apache 2.0 licence. This is a classic asymmetric grant because the Apache foundation receives far more rights in the contribution than it grants to the downstream recipients. The FSF CLA is even more extreme because they require assignment of the copyright (so they will own the code and you, the author, will have no further right or interest in it except possibly for minimal moral rights to be named the author). Apart from the asymmetric grant, which places the receiving entity in a privileged position in the ecosystem, the other problem with CLAs is that they’re legal agreements, so they require a lawyer to prepare them, a mechanism to ensure people sign them and a mechanism to keep all the signatures … sometimes this can be in filing cabinets if paper instead of electronic copies are used. This repository of agreements then isn’t available to anyone except the tracking entity, meaning that if someone needs to know if John Doe signed a CLA, they have to reach out and ask. In some cases the actual filing cabinets got lost as projects changed offices, so some CLA based projects don’t actually have complete records of all their CLAs.
CLAs Catalyse Community Corrosion
The main driver of community corrosion is the temptation to abuse a position of power (this temptation becomes irresistable over time because, as Baron Acton put it, “all power corrupts”). Since CLAs by their nature force a power imbalance between the contributor and the receiving entity, they act as focal points for this corrosion. Communities are very sensitive to what they see as their work being misused, so the fastest way to lose community trust is to abuse the power the CLA gave you to go against the community itself. There are numerous examples of this in the Corporate World, the most topical one today being the Elastic change from Apache 2.0 to SSPL to better monetize the code the community contributed freely to. One might think the solution to this is never to sign a CLA if the holder of the power imbalance is a corporation … i.e. only do it if the other entity is a not for profit foundation. But ask yourself, how much do you trust the people running the foundation and do its bylaws guarantee your rights in the code? Relicensing for commercial gain isn’t the only way the community could be abused, so how sure are you of the power you’re handing to a foundation which, after all, is an entity governed by some type of board, all of whom likely have political agendas, won’t be abused? To see some examples of foundations not being in tune with their community, one only has to look at the FSF and Richard Stallman. Based on all of this I conclude, like Drew DeVault, that you should never sign a CLA under any circumstances.
The bottom line is that if you do sign a CLA some decision will happen at some point that you don’t agree with but which you already gave away the power to block because of the rights imbalance inherent in the CLA you signed. Inevitably this decision will cause you to feel betrayed because your views are being ignored and as a contributor you feel you should be heard, so you’ll sour on the project. This is the community corrosion catalyst buried deep inside all CLAs.
One final thing to note is that it is possible to craft a CLA that only takes the rights it needs, in the same way the DCO does, it’s just that no project I know has ever done this. However, even if this experiment were attempted, you still need a recipient entity, plus all the infrastructure to do signing and track the signed agreements, so you’d still be better off using a lightweight DCO process.
Conclusion: For Community Small is Beautiful
The way to avoid the community corrosion problem is to do everything minimally: use a DCO to take only the rights the downstream requires and to avoid all the heavyweight recipient, signing and tracking infrastructure. Don’t set up a foundation unless you absolutely need an entity, say to handle cash, and if you must set one up, never give it any control over the project (like appointing a change control or architecture control board for instance) everything you set up should be as small as possible and clearly serve the project and its community. Above all, don’t use a CLA because it will cause a rights imbalance that corrodes your community and it will require a large amount of overhead to run.