How to protect a project from license infringement, without a CLA?

Question

I am considering releasing a project of mine using the GNU Affero General Public License.

I have been researching Contributor License Agreements, Developer Certificate of Origin, as well as the pros/cons of FSF-style Copyright assignment.

I would like to:

• Accept contributions to the project with the expectation that they are licensed under the AGPL
• Have the right to pursue violations of the license, without needing to get explicit approval/participation from all contributors
• NOT have the right to change the license of, or dual license, the code base

Is there a standard way to accomplish this within the existing FOSS ecosystem, other than requiring a CLA?

Answer 1

Everything you want is already possible without a CLA or copyright assignment.

• inbound=outbound is automatic for GPL-family licenses because it is not allowed to distribute modifications without offering them under the same xGPL license. Modifications to LGPL-licensed code can be distributed under the GPL, which could block you from receiving modifications under upstream-usable terms, but there is no similar transformation allowed for the AGPL

• It is not necessary to get approval of all contributors to litigate against infringement. It is only necessary that you own some part of the code being infringed. In other words, infringement can be litigated against by any copyright holder, not by some critical mass of all copyright holders. As long as you hold copyright to some part of the code being infringed, you have standing to sue infringers.

• Since other contributors retain their copyright, and you can make use of their contributions only under their AGPL grant, you will not have the ability to relicense those contributions.

One edge case that you will not be well-protected against without a CLA is if a contributor illegally offers a contribution that is itself infringing. (i.e., a contributor illegally offers someone else's code without permission) In at least some jurisdictions, you would be liable for passing along such infringing material, even if you didn't know it was infringing. (A defense may still be possible in some jurisdictions, but it would surely be simplified by the contributor's assurance beforehand that the contributor wasn't infringing.)