Fix arguments for sourced script

[baodrate]

Quality of life improvement for handling arguments, mostly useful for testing things on the command line.

Proposed Changes

Shifts around the arguments (and sets argv[0] to the target script) so that they would be as you expect if the call at the end of bashio was exec "$@" instead of source "$@".

From the bash manual:

If any arguments are supplied, they become the positional parameters when filename is executed. Otherwise the positional parameters are unchanged.

This makes handling arguments annoying, because there's no way other than testing [[ $1 = $EXPECTED_SCRIPT_PATH ]] to see if arguments were passed on the command line. And if arguments are passed, there's no way to access the true script's path

Example

given example.sh:

#!/command/with-contenv bashio

bashio::log.info "0='${0}'"
bashio::log.info "1='${1:-NONE}'"
bashio::log.info "2='${2:-NONE}'"

exec /bin/echo "$@"

prior to change:

$ /example.sh
[23:21:36] INFO: 0='/usr/bin/bashio'
[23:21:36] INFO: 1='/example.sh'
[23:21:36] INFO: 2='NONE'
/example.sh

$ /example.sh foo bar
[23:21:39] INFO: 0='/usr/bin/bashio'
[23:21:39] INFO: 1='foo'
[23:21:39] INFO: 2='bar'
foo bar

after change:

$ /example.sh
[23:21:47] INFO: 0='/example.sh'
[23:21:47] INFO: 1='NONE'
[23:21:47] INFO: 2='NONE'

$ /example.sh foo bar
[23:21:51] INFO: 0='/example.sh'
[23:21:51] INFO: 1='foo'
[23:21:51] INFO: 2='bar'
foo bar

[frenck]

Makes a lot of sense, thanks, @baod-rate 👍

../Frenck