to-html VS cargo-xtask

Using a build script to generate all completions at compile time (to-html currently does this)

I noticed you included shell ouput as HTML, with ANSI colors properly converted to CSS. That's awesome, and shows that we are like-minded people, since I've also written a tool for this purpose :D

💡 Inspired by matklad/cargo-xtask and based on 🏃‍♂️ Write your Rust project scripts in task.rs from the Rust ecosystem.

Using a cargo-xtask task to generate them as a manual step (inlyne currently does this)

As someone else said just is good for that job, or you could implement an xtask helper for these things and setup a suitable development environment with that: https://github.com/matklad/cargo-xtask/

Well tools like cornucopia, prisma-rust-client, protoc-gen-tonic, they don't generate in build.rs, but instead provide either a cli to be called ahead of time, or provide a library that can be called by your own binary (which should generally follow the xtask pattern)

If I understand, this is a tool for when working on the project itself? Akin to a helper script? You could go the cargo install route as already pointed out but there is also the xtask convention.

For simple cli apps for internal use, such as cargo-xtasks, I prefer pico_args due to its fast compile times.

For developer-oriented stuff, there's tools like xshell and cargo-xtask. For operator tasks that need to run in a deployed environment, it's not usually a big lift to add CLI subcommands to your binary. It's certainly more boilerplate and inertia than doing stuff in a live REPL, though, and sometimes difficult to recommend for truly one-off situations.