> contributed a minor improvement to Redis under its original license [...] feeling betrayed as a contributor to a properly-FOSS-codebase
How does this work legally? You write some code, contribute it under a certain license... and... a company can just re-license your code under any license they like?
They require a Contributor License Agreement [0] whereby you grant them the copyright to your contribution. Which means they become the ultimate decision-maker for all contributions and can relicense however and whenever they wish.
CyanogenMod required a CLA to assign them copyright to Cyanogen Inc, only for them to basically kill the project. They forked it as LineageOS only to still require a CLA.
IMO the anger people direct at source available licences would be better directed at CLAs. They're what hands the power away.
Don't contribute to projects with CLAs people without reading them carefully and understanding what can happen! Then you won't be surprised if a project is relicensed because you know you signed an agreement to let them do that.
How does this work legally? You write some code, contribute it under a certain license... and... a company can just re-license your code under any license they like?