How does one create development shells for packages under development?

[liarokapisv]

In normal situations, I can put specify a package under development within mkShell's inputsFrom list and it will automatically fetch its dependencies and make them available without building the package itself. Because nix-ros-overlay provides the buildEnv utility, I don't see a good way to achieve the same. I guess one could directly flatten a given package's (propagated)(native)buildInputs and put those inside buildEnv. What is the recommended approach here?

[kjeremy]

I'm not quite sure what you are asking but if I need to hack on a package that is in this repo (in this case roscore) I use something like nix develop .noetic.roscore and then run the unpackPhase and patchPhase before hacking on it.

[wentasah]

I think that flattening the dependencies of needed packages is a way to go. Doing that would be useful for me too, but I don't have any code for it. So if you come with some solution, I'd appreciate if you can share it.

[liarokapisv]

@kjeremy My usecase is maintaining a custom workspace with multiple packages under development. Ideally I would just list the derivation expressions for these in my shell's inputFrom in order to get a sane dev environment but this doesn't work due to the buildEnv. I don't think using nix develop is enough in this case otherwise buildEnv would not be needed.

[RandomSpaceship]

I know I'm late to the party, but would the buildROSWorkspace function (and resultant env attribute for the shell) of nix-ros-workspace work for you?

If you specifically need flattened dependencies, I'm currently developing on a flake-ified fork which does exactly that for ROS dependencies in the nix develop shell, since I've had my own issues with it. Feel free to use that code if it works for you, though I wouldn't recommend using my fork directly for the next couple of weeks since I might need to make breaking changes.

[liarokapisv]

Yes that one works, it's actually what I am currently using, just wanted to check that there is no any upstream alternative. I have no issues with nix-ros-workspace but generally it would be better to get first-class nix package support so that we don't need any buildEnv wrappers and just adding packages to inputsFrom directly would just work. Not sure how feasible this is.

[lopsided98]

You don't have to use buildEnv. It primarily exists because the environment variables can become too long with lots of ROS packages.