License Zero

gainful open software development

October 20, 2019

Parity 7.0.0-pre.3 fast approaching 7.0.0

Work on Parity 7 continues in the GitHub repo. Have a quick look through the latest version 7 prerelease, and as always, feel free to open issues and pull requests.

In particular, I’d be interested to hear about:

Full text and a few interline comments below:

The Parity Public License 7.0.0-pre.3

Contributor: [name]

Source Code: [source]


This license lets you use and share this software for free, as long as you contribute software you develop, operate, or analyze with it.

The linchpin of the copyleft rule is now the triplet “develop, operate, or analyze”. The use of “operate” comes directly from feedback comparing the verbs in Parity 6’s copyleft rules with various frameworks for breaking down “DevOps”, a combination of software development and IT operations.


In order to receive this license, you have to agree to its rules. Those rules are both obligations under your agreement and conditions to your license. Don’t do anything with this software that triggers a rule you can’t or won’t follow.

This draft uses contractions—“don’t”, “can’t”, “won’t”—throughout. That’s how English speakers talk, and it doesn’t hurt the license to make it more approachable.


Make sure everyone who gets a copy of any part of this software from you, with or without changes, also gets the text of this license and the contributor and source code lines above.

The rules specific to Parity now appear right at the top, rather than after the license grants. I’ve ordered the rules at the top in order of how frequently they will apply.


Contribute software you develop, operate, or analyze operate with this software, including changes or additions to this software. When in doubt, contribute.

Prerelease 2 said “develop, study, or operate”. I’ve moved “operate” directly after “develop” to jog more memories about “DevOps”. “Study” could imply analysis for a specific purpose—education—while “analyze” avoids that tinge of specificity.


You don’t have to contribute any change, addition, or other software that meets all these criteria:

  1. You don't use it for more than thirty days.

I’ve shortened “calendar days” to just “days” throughout.

  1. You don't share it outside the team developing it, other than for non-production user testing.

Prerelease 3 allows sharing prototypes outside development teams for non-production user testing.

  1. You don't develop, operate, or analyze software with it for anyone outside the team developing it.

Here’s “develop, operate, or analyze” again.


When this license requires you to contribute software:

  1. Publish all source code for the software, in the preferred form for making changes, through a freely accessible distribution system widely used for similar source code, so the contributor and others can find and copy it.

  2. Make sure each part of the source code is available to the public under a license that gives as much or more permission as this one, such as Blue Oak Model 1.0.0, Apache 2.0, MIT, or two-clause BSD.

The phrase “gives as much or more permission” requires the same as “at least as permissive as” without tripping over a quasi-term of art in open licensing that caused confusion. Parity will not be classed a “permissive license” like Blue Oak, Apache, MIT, or BSD. The point is that developers can use permissive licenses if they like.

  1. Take these steps within thirty days.

  2. Note that this license does not allow you to change the license terms for this software.


You are excused for unknowingly breaking Copyleft if you contribute as required, or stop doing anything requiring this license, within thirty days of learning you broke the rule. You are excused for unknowingly breaking Notices if you take all practical steps to comply within thirty days of learning you broke the rule.


Don’t make any legal claim against anyone accusing this software, with or without changes, alone or with other technology, of infringing any patent.

The contributor licenses you to do everything with this software that would otherwise infringe their copyright in it.


The contributor licenses you to do everything with this software that would otherwise infringe any patents they can license or become able to license.


The contributor can’t revoke this license.

No Liability

As far as the law allows, this software comes as is, without any warranty or condition, and the contributor won’t be liable to anyone for any damages related to this software or this license, under any kind of legal claim.