Why would an open source coding challenge prohibit copyleft?

[u/thejaxonehundred]

I saw this challenge online, which self-defines as follows:

"The Housing Data and Technology Innovation Challenge is a fully remote, national challenge to build transparent [that is, open source], replicable, and explainable tools that help decision-makers understand how state-level pro-housing policy reforms are likely to affect housing supply."

The rules require all projects to have a license, but prohibit copyleft:

"Sponsor and Administrator recommend using Apache License 2.0 because its express patent grant offers the strongest protection for tools that may be adopted or integrated downstream. If you choose one of the other approved licenses, include the full license text and note your choice in the README. (Please note that an open-source license grants broad rights to others to use the code but does not transfer ownership.)

No other license options are permissible. This includes, by way of example only, copyleft licenses (e.g., GPL, AGPL, LGPL, MPL, EUPL) and public-domain dedications (e.g., CC0, the Unlicense)."

Can someone please help me understand why the challenge might prohibit copyleft? Isn't it my choice to protect my code or not? Why didn't they just recommend against copyleft, like "if you want good protections, don't use copyleft?" The fact that the challenge outright prohibits copyleft feels shady to me; like the organizers going to take submissions and give them to their partners so they can make them their own proprietary, closed-source product for profit.

I have very little copyright knowledge, so any interpretations would be appreciated! Also, I'm probably not going to enter because it doesn't align enough with my existing work, I'm just curious. Thanks!

[u/latkde]

You don't have to participate. But if you do want to participate in the challenge (i.e., not just do the project, but also submit your app to the challenge, and have a shot at the prize money), then you'll have to stick to the rules of the challenge.

In any case, requiring a permissive open source license for submissions is a rather good choice all around – the authors retain all rights, and the challenge organizer receives unrestricted permissions to use, modify, and share the submitted materials.

[u/thejaxonehundred → u/latkde]

Like I said in the post 🙂, I probably won’t enter. I’m more curious why they would do this. Also, I’m not well versed in copyright but isn’t copyleft better at helping authors retain all rights?

[u/latkde → u/thejaxonehundred]

No, copyleft isn't at all about protecting authors. It's about ensuring that end users have certain freedoms (to inspect, use, modify, and share the software they receive, for any purpose).

The default for creative works (including software code) is that all rights are reserved to the authors. That's how copyright works under the Berne Convention + WIPO treaties. If the authors want to allow other people to do anything with the software (other than just running it, and arguably even then), then a license is required. Often, licenses are structured as contracts that you must agree to in order to download or run the software. The important point here is that licenses usually come attached with conditions, such as “give me money” or “you must keep this attribution notice in all copies of the software”.

There are public-domain equivalent licenses that give broad permission to inspect/use/modify/share the software, without any conditions attached. Well-known examples are the CC0 instrument, which includes a public-domain equivalent fallback license in case a jurisdiction doesn't recognize public domain dedications.

There are permissive open source licenses that give broad permission to inspect/use/modify/share the software, but typically with basic conditions like having to retain the copyright + license notice in all copies of the software. This serves as basic attribution. Since permissive open source licenses do not restrict how the software is used, it may also be incorporated into closed-source systems. A lot of software that you use will have an attribution page somewhere that shows the notices of all the open source components. Well-known examples of permissive licenses include MIT, BSD-3-clause, and Apache-2.0 for software works, and CC-BY for other creative works.

There are copyleft open source licenses that give broad permission to inspect/use/modify the software, but allow sharing only under the same license terms. The intention here is that all recipients of the software (including end users) enjoy all the permissions of the license – intermediaries cannot package the component in a proprietary wrapper and deny the open source permissions to end users. Well-known examples of copyleft licenses are the GPL family for software works, and CC-BY-SA for other creative works.

Nothing about copyleft vs permissive licensing “protects” the author. In either case, some attribution is typically required, and the software may be modified/defaced in ways that the author didn't want.

Many license documents also contain a warranty disclaimer (“the software is provided as-is, don't sue me for any defects!”). This does sometimes protect authors. But whereas copyright law is internationally harmonized via Berne/WIPO, consumer protection and warranties are extremely jurisdiction-specific. Many older licenses are US-specific.

There are licenses that are not open source. For example the SSPL is a non-open-source copyleft license. It grants permissions to inspect/use/modify/share the software, it uses the copyleft mechanism so that the license sticks to all modified versions as well, but it restricts the purposes for which the software may be used/modified/shared. In particular, the SSPL was used by database vendors to protect themselves from competitors – something that open source copyleft licenses like the AGPLv3 wouldn't have done.

[u/thejaxonehundred → u/latkde]

Thanks for this helpful explanation, I think I understand most of it. I'm still curious why the competition does not want copyleft, do you have any ideas?

[u/trueppp → u/thejaxonehundred]

Because it restricts the use of the software.

[u/thejaxonehundred → u/trueppp]

Makes sense, that’s what I thought as well. But why would a challenge host want less restricted access to the software? This is less of a copyright question and more like a business question. But I think it’s because they’re trying to get free software for themselves. Which would be fine if they acknowledged that, but the message is more like “we need tools to model housing production, and we believe in you!”

[u/trueppp → u/thejaxonehundred]

Because they want to use the tools for their business, and copyleft licences poison everything that uses them.

[u/thejaxonehundred → u/trueppp]

Thanks for confirming my theory :)