When using yarn with the nodejs plugin, the yarn binary is not in $PATH

[Leo Arias]

I was trying to build a snap for ethereum's mist. It uses yarn as the package manager, but it has an entry in package.json that we don't support:

"postinstall": "cd interface && yarn"

https://github.com/ethereum/mist/blob/develop/package.json#L11

Trying to build this snap will fail with:

error /home/elopio/mist/parts/mist/src/node_modules/Mist: Command failed.
Exit code: 127
Command: sh
Arguments: -c cd interface && yarn
Directory: /home/elopio/mist/parts/mist/src/node_modules/Mist
Output:
sh: 1: yarn: not found

In order to support this use case, during the pull and build, the commands need to be able to execute parts/<name>/bin/yarn.

[Sergio Schvezov (sergiusens)]

It was like that on purpose, it was clearly a mistake.