Exec inside a function does not work

[faho]

$ function ouch
     exec fish
 end
$ ouch
There are still jobs active:

   PID  Command
     0  ouch

as described by @scorphus on gitter, and oh-my-fish/oh-my-fish#664.

This is caused by us checking for running jobs before doing exec now (1b1bc28), in conjunction with the hierarchical job changes.

I think we might just get away with warning only with background processes (i.e. those where is_foreground() is false). @mqudsi?

The obvious question is if this is important enough to warrant a 3.0.1, or a quick 3.1.

[mqudsi]

I would say if you publish now, it's a quick 3.0.1. If you put it off, it might become a 3.1.

[JamesMcMahon]

I would second that as this will keep me from upgrading to Fish 3 due to it completely breaking OMF.

The issue behavior described in oh-my-fish/oh-my-fish#664 is not a great user experience:

Yah, iterm2 hangs on startup macOS after updating to fish 3.0.0 with OMF 6.0.

[ridiculousfish]

This went into 3.0.1 as 60ced5d