bash4 was released Feb 2009. 16 years ago.
The very latest version of osx ships with bash3, from 20 years ago.
It's a fair question, and "currently supported" is essentially meaningless.
(Yes we all know about macports and the other more popular but less correct systems, and yes most bash scripts should be written to specifically avoid relying on any special features exactly to avoid being broken so easily. These are both true and both beside the point. Fact is still, this is not only a "currently supported" system by some technicality like the final months of a 5 year lts release or something, this is the up to this very minute version of a massive install base, with a 20 year old version of something as basic and all-touching as the very shell itself.
I know about this so intimately because I actually have scripts that don't work because they were intentional stunts to see just what could be done without forking any external exes or even child shells, but allow using every possible feature and trick in bash itself.)
It doesn't matter why. All that matters is that "current" is not a valid word. Old things exist in "current" systems. And current systems may also be old systems.
Ok. I think engineers are well capable of evaluating what systems they need to support and if zstd is a usable option for them. In many situations, the answer will be "yes."
You can download a supported zstd release through homebrew for every version of macOS that is supported by Apple (as those are the releases homebrew supports), and it compiles from source for older ones.
I don't even know why we're talking about bash here. But for the record, this is a unique circumstance that affects only software which made the transition from GPLv2 -> GPLv3. Changing your license can cause you to fork away from some users. News at 11.
You can get bash4 or 5 too, as I already said. I can't help you with your depth of experience. I didn't even say zstd was unfit to depend on, just that it was a fair question.
Once again, I’m having to remind a person that coding is a team sport and personal choices are bullshit.
Every deviation you make from stock is something else you have to put into. The onboarding docs and convince all your coworkers to install. They won’t. Or they think they will but will miss a step or machine. Or for language specific tools, they’ll use a multiversion tool like asdf or nvm or ram and have to reinstall again every upgrade.
It’s not up to me. It’s not up to you. It’s up to us. And if you can’t see that, maybe you shouldn’t be working with other developers. Or maybe you haven’t been and you need to.
Java 8 will be supported until 2032 if you pick the right distro, and that distro comes with zstd in the repos (if not pre-installed).
And if your system is so old that you don't have access to eight-year-old software, I don't see why the rest of the world needs to accommodate you. Sticking with weird and old software is fine, but that comes with the risk of having to deal with everyone else moving on.
