Run mix task in one (or a few) selected umbrella app children

I don’t think there is a way to do it, but maybe I am wrong.

Can I run a mix task for one of the apps in umbrella project, without running it recursively on all apps, and without changing my shell working directory to the apps/myapp?

If I change working directory and run the task, it works, but it forces the app to be recompiled to within the directory, so it’s slower.

The answer is “nope”.

If your project recompiles after you cwd into umbrella app, make sure your config in child apps is correct and includes those lines:

 build_path: "../../_build",
 config_path: "../../config/config.exs",
 deps_path: "../../deps",
 lockfile: "../../mix.lock",