[steveklabnik]

It appears both clap 2 and clap 3 have packages in bookworm. Were you trying to use them from crates.io instead of apt? Clap is on version 4 there.

> how is one supposed to go around such a task, by the way?

There is not great tooling for this, because most people use the latest stable when starting a new project, and then rust being backwards compatible means things Just Work into the future. A vanishingly small number of folks use builds significantly older than that, since upgrading is generally trivial, and newer compilers have faster build times and better error messages.

[defanor]

Oh, I have not tried using it from system repositories: I tried that with another library (in a hobby project) before, had issues with that, been told and generally gathered that it is easier to pull dependencies with cargo, so went straight to that this time. I see that librust-clap-dev would pull 157 other packages with it though, but will look more closely into it: I would actually prefer getting dependencies from system repositories, thanks for pointing it out.

As for newer compilers, I prefer to depend on system repositories and package manager for updates, and to stick to stable branches, so that things do not change too often. I see the appeal of rolling release distributions and cutting edge software, but not feeling comfortable using it for things that are supposed to be reliable.

[steveklabnik]

So to be clear, I do not recommend that you use the rustc provided by Debian for general development. But if that’s what you want to do, by trying to mix a rustc from Debian with packages from the general ecosystem, it is going to be the worst of both worlds. I would ignore crates.io if I were trying to do what you’re trying to do. You’ll have less access to packages overall, and be using older versions, but they’re at least known to work with each other and that specific rustc version.