Re-implementing MIT licensed software in another language

Question

I have re-implemented a library in Golang which was originally in Python.

The original Python library carries an MIT license, which gives me "without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense".

Could I put my own MIT license to my implementation? Do I need to also furnish the copyright notice of the original author's Python library along with mine?

This question is similar to this question How to use MIT license in a project? except that I have not done significant modification but almost literal translation.

Answer 1

If the original library would be licensed using a copyleft license, the matter would be clear:

What does the GPL say about translating some code to a different programming language?

Under copyright law, translation of a work is considered a kind of modification. Therefore, what the GPL says about modified versions applies also to translated versions.

https://www.gnu.org/licenses/gpl-faq.html#TranslateCode

We can use this reasoning to answer your question. You, too, created a modified version of the original library. Therefore you are bound to the license conditions of the library. The MIT license only requires attribution, which you have to give. So your software must give proper attribution as you would have to do if your software included the original Python version.

The MIT license allows you to use any license you want for your software. This, of course, can also be the MIT license, now with you as the author.