As multiple people have commented, (#512, #333, elsewhere),git-secret is getting a little big and complex for a bash program. Also, there are features we'd like to add that would be easier to implement in other languages, notably https://github.com/sobolevn/git-secret/blob/master/RFC/RFC001.md .
It's true that being a bash script has probably made installation and acceptance of git-secret easier for people, but I think we might be past the point where the downsides of git-secret using bash outweigh the benefits.
When compiled to a single script, git-secret (without tests or build infrastructure) is about 1929 lines, and over 1/3 of that is whitespace, leaving only approx 1200 lines of code and comments, so there isn't _that_ much code to port.
All of this is to say that it might not be that hard to submit a PR that ported/rewrote git-secret into another language. For ease of migration, it would be possible to rewrite the git-secret script and continue to use the existing test/build frameworks, adding whatever dependencies are needed. It would be a bonus (but not a requirement) if the corresponding rewrite was shorter than the bash version!
We're separately open to migrating the test code (to match the git-secret script rewrite probably).
How about Rust? I recently started writing some little programs with it. And it seams like a good choice for git-secret.
@joshrabinowitz what do you think about rust version? There are plenty of libraries to work with gpg from rust: https://crates.io/keywords/gpg
I'm starting to learn Rust and would be interested in helping out with a rewrite.
I'm sort of language agnostic at this point, although I think using a language that compiles to a binary would help ease distribution. C or even C++ seem logical too.
What I'd like to see is versions of git secret init and perhaps git secret tell implemented in a few different languages. Then we can decide which we like best.
Also I think it makes sense to have the initial rewrite use gpg commands under the hood, for ease of porting and to have less moving pieces at once. Once we have it working 'shelling out' to gpg commands, we can migrate the rewrite to use native gpg libraries if we want to.
Just a quick update: since my rust skills are very low (that's why I want to write something serious with it) I am quite slow with the rewrite. But, I am working on it.

Progress will be here: https://github.com/sobolevn/git-secret-rust Later we can discard that repo or merge it into this one.
@sobolevn excellent, interested to follow along with and perhaps contribute to your progress!
Hello, @sobolevn, any progress on the Rust version?
Sorry, I was quite busy with some python stuff during the Hactoberfest season. I would be back to rust in November.
Hello @sobolevn , just wondering how this is coming along.
Maybe you could check in what you have so far so others can continue/contribute to your work in Rust?
Yes, totally the project got stuck for work reasons. I will just upload everything I have at the moment.
Tomorrow morning. I invite you @joshrabinowitz to the repo. Thanks for reminding! 馃憤