This is not a scenario I'm actually going through; this is just a thought I had. The situation proposed in this question is entirely hypothetical.
Suppose some algorithm -- for this post, let's say something compression-related -- is patented in the United States. But the patent is going to expire within a year. I want to add this algorithm to an established project of mine, which is open source and sees both personal and commercial usage. Is it legal to privately develop a feature for this project that infringes upon this patent, but withhold releasing it until the day after the patent expires?
For the sake of this post, assume the following:
- All Git commit history is available and commits are signed; once the patch is released it will be known that I (and possibly others) have worked on this infringing feature while its patent was still active.
- I might or might not have announced my development of this patch; I didn't exactly go on a big media blitz about it, but I could have dropped a vague hint (or even an explicit confirm) via Twitter or similar. I never outright lie about it, though.
- The infringing patch is not publicly accessible until the day after the patent expires, but it (or some parts of it) might still have been transmitted to other parties, either for collaboration purposes (e.g. with a friend, storing the patch on his personal server) or when seeking help on support communities like IRC, mailing lists...or StackExchange.
- The patch is tested and feature-complete upon release.