Handle case where nodenv-commands --sh returns nothing

[aphedges]

In exceptional cases (e.g., custom installation, malfunctions elsewhere), nodenv-commands --sh may return nothing. In non-Fish shells, this would cause "syntax error near unexpected token )'" in nodenv()`.

Bash does not allow one to specify a case option without a pattern. We work around it by defaulting to /. Commands, being filenames, can never match it. In Fish, nothing needs to be done: it apparently does interpret a case without an argument as one that never matches.

This patch is based on 02e1d4a¹ from pyenv, which was written by @ native-api and I.

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Feel free to edit the commit message as needed, but I would appreciate if you kept most of it. I sometimes find it useful to grep the Git logs when developing.

If you want to see some discussion about the original patch for pyenv, look at pyenv/pyenv#2908.

Footnotes

1. https://github.com/pyenv/pyenv/commit/02e1d4a293139ecf2c94206ee9c00b388550366e ↩

[jasonkarns]

Is there a corresponding PR for rbenv?

[aphedges]

@jasonkarns, no, not unless someone else made one. I can do that, if you require patches to be upstream first.

[jasonkarns]

We don't require it, no. But I wanted to make sure the work isn't duplicated since we do pull from upstream somewhat regularly.

If you're comfortable opening it there, it's easier to start in the rbenv repo. If not, we can leave it here and I'll see about moving it upstream later.

[aphedges]

I can make a PR in rbenv soon to better match your workflow. I'm more used to working with pyenv, which I don't think has had changes merged from rbenv in years.

If it gets accepted upstream, then I'll close this PR.

[jasonkarns]

Thank you, that would be helpful. Even if it gets merged upstream, it's probably best to keep this issue open here until that fix gets pulled downstream as well.

(And we may merge this one in advance anyway once I get a chance to dig into it)