10

The first part of the license implies you can do basically whatever you want with it (copy, modify, sell etc). But the second part says that these freedoms must propagate into all copies of the software.

My interpretation of that is, you can incorporate the software into your proprietary project, but that portion must remain open....so any modifications to the software must keep that license attached, forcing my changes to be open sourced.

Isn't this the reason people consider the GPL to be restrictive/viral? Because it forces modifications to be open sourced?

Here is a copy of the license:

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

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19

Not quite.

Here's the basic idea. As you pointed out, "you can incorporate the software into your proprietary project, but that portion must remain open" under the MIT license. If you have 100 features in your proprietary product, and one of them is based on MIT-licensed code, that's fine.

However, if you have 100 features in your product, and one of them is based on GPL-licensed code, the GPL forces you to open-source the entire rest of the product. That's why it's called a viral license: it doesn't stay in its own code, but "infects" the rest of your codebase as well.

  • 11
    The MIT license does not require anything to "remain open" it only requires you to include the copyright notice. Not the source code. – Craig May 2 '13 at 15:39
  • @Craig: so, I include that notice in my source file and I don't have to deliver the MIT license to my customer? If I deliver that license file to my customer, he cannot know to which feature it applies and to which features it does not apply. – Thomas Weller Feb 25 '17 at 21:07
  • @ThomasWeller you would include a notice like "Includes software foo under MIT license, blah blah blah" if you would like an example see chrome://credits – Craig Mar 4 '17 at 4:11
15

The GPL is considered viral because, if you combine software that is licensed under it with proprietary code, you must also open-source your proprietary code under the GPL in order to remain compliant with the GPL.

The MIT license doesn't say that at all.

I think you might be interpreting the term "The Software" to include your proprietary portion. It does not. The MIT license only covers that part of the software which is licensed under the MIT license.

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