- [x] Have you followed the [guidelines for contributing](https://github.com/snapcore/snapcraft/blob/master/CONTRIBUTING.md)? - [x] Have you signed the [CLA](http://www.ubuntu.com/legal/contributors/)? - [x] Have you successfully run `./runtests.sh static`? - [x] Have you successfully run `./runtests.sh tests/unit`? ----- This PR fixes errors when running the nodejs plugin with the base keyword. I am now running `npm install` with `--unsafe-perm` and `SUDO_UID` unset. When building in a VM, node will crash upon running certain scripts because it drops the root UID when running them. It will sometimes ignore `--unsafe-perm` on certain commands, such as running `git` during a `npm install` that has a `git:` dependency, and the only way to override that is to drop `SUDO_UID`. I am no longer running `npm install` during the pull step because: 1) It adds a significant amount of build time between the 'pull' and 'build' step, because it has to copy the project directory to the build directory and `node_modules` can be hundreds of thousands of files. 2) It is often the case that changes need to be made during the build process in between downloading node/npm/yarn and running `npm install`, such as importing private packages, setting custom a registry, etc. Without the ability to run `override-pull` before `npm install`, the pull step will crash. I also skip running `npm ls` and populating the `manifest["node-packages"]` if yarn is used, because yarn often creates different dependency trees and it will crash the build if `npm ls` detects that the dependency graph (that npm would have generated) is missing dependencies.