### Bug Description **Problem 1** (solved; see below) The `npm` plugin installs NodeJS during the build step: https://github.com/canonical/craft-parts/blob/2b16c15d81e9ed6ffef6a3d1074b6482953cd38c/craft_parts/plugins/npm_plugin.py#L179-L197 When building a ROCK, if we use `override-build` to customize the invocation of `npm install` as needed by our application, we don't get NodeJS installed. So we have to either download and install NodeJS ourselves, or resort to hacks like building the application during the stage step. For building this ROCK, we found a nice workaround using `overlay-script`, which is good enough for us for now to install NodeJS independently: > The overlay step provides the means to modify the base filesystem before the build step is applied See: https://canonical-rockcraft.readthedocs-hosted.com/en/latest/explanation/overlay-step/ --- **Problem 2** Somewhat related to this: the download of NodeJS should also ideally have its checksum verified to mitigate the impacts of any supply-chain-attacks and eliminate the problem of corrupted downloads, maybe doing something similar to what Docker does: https://github.com/nodejs/docker-node/blob/1fc16c3d1ea2be71fba69115f59d0e8f99876692/18/buster/Dockerfile ### To Reproduce Try to try to build any application whose `npm install` process needs to be customized to be different from the default dictated by the part. ### part yaml _No response_ ### Relevant log output ```shell - ```