Add LIMA_SHELL env var to lima command

[jandubois]

$ export LIMA_INSTANCE=alpine
$ lima sudo apk add fish
[...]
$ export LIMA_SHELL=/usr/bin/fish
$ lima
Welcome to fish, the friendly interactive shell
Type help for instructions on how to use fish
jan@lima-alpine /U/jan>

Split off from #779.

[AkihiroSuda]

Wondering rather we should have a generic way to support limactl shell options in the lima script. Perhaps like LIMA_SHELL_ARGS=--workdir=/ --shell=/bin/zsh. But on the second thought maybe users should just set alias lima=limactl shell .....

Originally posted by @AkihiroSuda in #779 (comment)

[jandubois]

should have a generic way to support limactl shell options in the lima script

Practically speaking, we only have 2 options: --shell and --workdir, and I don't really expect somebody to hard-code the workdir for each lima call. But even then, I would rather add another LIMA_WORKDIR variable instead, so the options can be manipulated independent of each other.

[AkihiroSuda]

we only have 2 options

Eventually we will have more

[jandubois]

Yeah, but I still like having individual variables. This is how I would do it:

set - "$LIMA_INSTANCE" "$@"
if [ -n "${LIMA_SHELL}" ]; then
  set - --shell "$LIMA_SHELL" "$@"
fi
if [ -n "${LIMA_WORKDIR}" ]; then
  set - --workdir "$LIMA_WORKDIR" "$@"
fi
exec "$LIMACTL" shell "$@"

This is trivially extensible to additional settings.

[jandubois]

I've updated the PR to include support for LIMA_WORKDIR as well (and rebased on top of master, so the --shell option is actually functional.

[AkihiroSuda]

CI failing

Warning: Attempt 1 failed. Reason: Child_process exited with error code 1

bash: line 1: ./hack/test-upgrade.sh: No such file or directory
Warning: Attempt 2 failed. Reason: Child_process exited with error code 127

bash: line 1: ./hack/test-upgrade.sh: No such file or directory
Error: Final attempt failed. Child_process exited with error code 127

https://github.com/lima-vm/lima/runs/5864063545?check_suite_focus=true

[jandubois]

CI failing

Seems like CI flakiness; it passed on re-run.