Please give opinions on this hypothetical open source license.

Question

I've concocted an open source license in my head that I feel is a good compromise between copyleft and permissive licenses. I think it extracts many of the benefits of copyleft with few of the downsides. Here's a rough draft of it. The spirit of it is that a company should be able to profit by adding value to open source software, but should be required to compete on a level playing field with the open source version and should be prevented from practicing embrace, extend, extinguish. Do you believe this would be a good license to use on an open-source project? (The part in bold is the part that's not standard BSD license material.)

Copyright <year> <copyright holder>. All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other
   materials provided with the distribution.

   3. If any derivative work of this software is distributed by you, the source code to all functionality necessary for interoperability with the original software, including but not limited to implementations of file formats and network protocols modified from or not present in the original software, must be distributed with the derivative work and all redistributions of the derivative work. If you own patents on any technology necessary for interoperability with the original software, by distributing a derived work of this software you hereby grant a worldwide, royalty free license to all persons receiving a copy of the derivative work to use this patented material for any purpose.

THIS SOFTWARE IS PROVIDED BY <COPYRIGHT HOLDER> ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Answer 1

Could your desires

The spirit of it is that a company should be able to profit by adding value to open source software...

Be achieved through dual licensing? Here is an answer I wrote regarding dual licensing, derivative works and commercial use. Basically couldn't the open-source entity sell a license to commercial groups, who can extend it and add their own value?

Answer 2

The wording of paragraph 3 seems to allow someone to distribute JUST the source-code for reading/writing file formats with none of the source-code that tells the downstream developer what they mean. Or at least they can try to do that, and everyone can spend the next decade fighting court battles.

Software developers should NOT attempt to write software licenses. They have no idea what the words mean IN A LEGAL CONTEXT. Ask a lawyer, and they will tell you the same thing.

As a software developer / potential entrepreneur, I would not release my code under this license. I'd go for a GPL-3 + commercial dual-licensing model. I would also be exceedingly wary of creating derived work based on this license, because of the legal uncertainty.

Answer 3

Please see:

Should I ask online programming communities like Stack Overflow for licensing advice?