Add --install option when sourcing nvm.sh

[mgol]

In my Jenkins setup, running on Bash 4.3.11(1) on Ubuntu 14.04.1 LTS, nvm is installed in the following way:

git clone https://github.com/creationix/nvm.git ~/.nvm
cd ~/.nvm
git checkout `git describe --abbrev=0 --tags`

This results in checking out 0.17.2 currently. Then, in the run script it's activated via:

. ~/.nvm/nvm.sh

which errors with N/A version is not installed yet, breaking the build. If I don't require all commands to end with status 0, and invoke nvm install with .nvmrc concaining 0.10 afterwards, it works fine.

The only problem seems to be the initial error.

[ljharb]

The code at the end of nvm.sh is designed to always return a zero exit code - when I have no default specified or .nvmrc file present, I get no error sourcing nvm.sh.

However, I do see that if I have a .nvmrc file referencing a not-yet-installed version, it will output that error.

Certainly this might be surprising the first time you source nvm.sh - but what would you expect to happen every time you open a shell, if you have a .nvmrc that refers to an uninstalled node version?

Could you perhaps wait to create a .nvmrc file until after you've installed the version you want to use?

[mgol]

Could you perhaps wait to create a .nvmrc file until after you've installed the version you want to use?

That doesn't fit the scenario... We have the .nvmrc file in the repo so that it's clear on which Node version we need to test. Then, in the Jenkins run we download nvm, activate it and do nvm install in the repo directory to download and activate the requested Node version.

We would have to cache the .nvmrc contents, delete the file, install nvm, activate it, then recreate .nvmrc and do nvm install... You can see it's not exactly an ideal solution. :)

[mgol]

There are many solutions to my problem that doesn't require to resign from the logic you describe; perhaps ~/.nvm/nvm.sh --install could try to install the requested version and not fail if that succeeds?

[ljharb]

I like that suggestion; I'll take a look at that.

[ljharb]

@mzgol I can definitely add support for . $NVM_DIR/nvm.sh --install - however, if it was already installed, that would output something like "v0.10.32 is already installed." to stderr. Would that be acceptable, since it would still exit zero and otherwise function?

[mgol]

@ljharb Sure! I just care so that it doesn't error. :)

[ljharb]

I'm having trouble with this since it seems like dash and sh don't allow options to be passed when sourcing something. I also tried using environment variables, but it seems that dash, at least, will automatically export env vars - ie, FOO=1 bar will leave $FOO set to "1" if it was previously unset.

(see http://unix.stackexchange.com/questions/5024/passing-a-variable-to-a-bash-script-when-sourcing-it-in-another-bash-script)