tasks.*.run templates: add shell escaping for arg() and option()

[powerman]

In v2024.11.0 both arg() and option() returns their values as is. As their values are supposed to be used in a shell command's param they needs to be escaped (using rules depending on current tasks.*.shell value).

Partial workaround is to surround them in a single quotes (e.g. '{{ arg(name="a") }}') - but this way we won't be able to use single quote itself in values.

Another but related issue: arg(var=true) and option(var=true) currently join list of their values using single space and this makes it impossible to correctly split it back to a list of values (which can itself contain spaces, quotes, shell wildcards, etc.). As a result currently it can be used only for list of values which does not contain any spaces/quotes/shell wildcards/etc.

[jdx]

As their values are supposed to be used in a shell command's param

not always, imagine this:

[tasks.run]
run = """
node <<EOF
console.log('{{arg(name="a")}}');
EOF
"""

I think it would be a mistake to blindly escape everything. We could add an escape=true option though.

[powerman]

Sure, sometimes you may need unescaped value. But if we had to choose between "always escaped" or "always unescaped" - then it's first! 😄

Probably escaping can be done using filter function in templates. This way you can control which arg/option to unescape. Just please-please-please make escaping default behaviour, so that extra filter will mark value as "raw, don't escape it".